WorldWideScience

Sample records for in-738lc in-939 nimonic

  1. Precipitate microstructure evolution in exposed IN738LC superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Strunz, Pavel, E-mail: strunz@ujf.cas.cz [Nuclear Physics Institute ASCR, CZ-25068 Řež near Prague (Czech Republic); Petrenec, Martin [Institute of Physics of Materials of the AS CR, Brno (Czech Republic); Gasser, Urs [Laboratory for Neutron Scattering, PSI, CH-5232 Villigen (Switzerland); Tobiáš, Jiří; Polák, Jaroslav [Institute of Physics of Materials of the AS CR, Brno (Czech Republic); Šaroun, Jan [Nuclear Physics Institute ASCR, CZ-25068 Řež near Prague (Czech Republic)

    2014-03-15

    Highlights: • Evolution of γ′-phase morphology in IN738LC Ni-base superalloy was examined by SANS. • In situ tests at high temperatures revealed trimodal precipitate distribution. • Formation, dissolution and (slow) kinetics of small γ′ precipitates was determined. • Equilibrium volume fraction of γ′ phase is significantly higher than 45%. • The small γ′ precipitates arise regardless the application of the mechanical load. -- Abstract: Nickel base superalloy IN738LC has been studied after low-cycle fatigue by Small Angle Neutron Scattering (SANS). Samples subjected to high-temperature low-cycle fatigue were annealed at various temperatures to change the size and the distribution of precipitates. Ex and in situ SANS and TEM studies were performed. It was found that additional precipitates are formed either during slow cooling from high temperatures or after reheating above 570 °C. Their size and distribution were evaluated. The precipitates arise regardless the application of the mechanical load. Nevertheless, these small precipitates influence low-cycle fatigue resistance. From the SANS data, it can be also deduced that the equilibrium volume fraction of γ′-precipitates at temperatures from room temperature to 825 °C is significantly higher than 45%. The kinetics of formation of small and medium-size γ′ precipitates at 700 and 800 °C was determined as well.

  2. Microstructure evolution in polycrystalline IN738LC in the range 1120 to 1250 C

    International Nuclear Information System (INIS)

    Balikci, E.; Raman, A.; Mirshams, R.A.

    1999-01-01

    The evolution of different microstructural features in the superalloy IN738LC, held in the temperature range 1120 to 1250 C and water quenched, is investigated in this study. The γ' precipitate formed in IN738LC grows continuously in cuboidal shape at temperatures up to 1130 C, but a distinct duplex-size (very fine + coarse) precipitate morphology develops when the alloy is water quenched from the range 1140 to 1150 C. Quenching from 1160 to 1225 C produces a single fine-size precipitate microstructure, while analogous quenching from 1235 C and 1250 C produces no precipitate at all. Very fine precipitates (∝40 nm size) are formed after a short time dwell in the duplex-size range and they grow to the size of the normal fine precipitates (∝70 nm) obtained upon quenching from the range 1160 to 1225 C. The fine ones do not grow beyond about 70 nm size in the duplex-size microstructure or in the single fine-size precipitate microstructure, even after very long time holding at the respective temperature range. Two different heat treatments were used to study the mechanism of precipitation leading to the duplex-size and the single fine-size precipitates. In treatment I, fine γ' precipitates (∝70 nm in size) obtained after 1200 C/4 h/WQ (water quenching to room temperature) solution treatment were subsequently allowed to coarsen in the temperature range 1140 to 1160 C

  3. The mechanical properties of the polycrystalline investment casting superalloy IN738LC

    International Nuclear Information System (INIS)

    Im, H.J.; Banerji, A.

    1995-01-01

    The mechanical properties of the polycrystaline investment casting superalloys, IN738LC in the present case, require an optimization of the microstructure. This is generally achieved by suitable founding measures as well as through the subsequent heat-treatment. Thereby, however, it is necessary to control the casting and solidification parameters. In the present study, additional measures have been adopted to inoculate the melt with a suitable chemical additive with the aim of obtaining a uniformly distributed fine equiaxial cast microstructure throughout the test-specimen. The addition of a suitable refiner substance increases the nucleation sites within the melt, which results into a fine equiaxial solidification. This imparts better casting properties thereby improving most of the mechanical properties significantly. The present report deals with refinement of cast microstructure through melt-treatment with chemical additions under varying casting and solidification parameters, wherein the grain size and dendrite arm spacing (DAS) have been quantified. (orig.) [de

  4. Implementation of a structural dependent model for the superalloy IN738LC in ABAQUS-code

    International Nuclear Information System (INIS)

    Wolters, J.; Betten, J.; Penkalla, H.J.

    1994-05-01

    Superalloys, mainly consisting of nickel, are used for applications in aerospace as well as in stationary gas turbines. In the temperature range above 800 C the blades, which are manufactured of these superalloys, are subjected to high centrifugal forces and thermal induced loads. For computer based analysis of the thermo-mechanical behaviour of the blades models for the stress-strain behaviour are necessary. These models have to give a reliable description of the stress-strain behaviour, with emphasis on inelastic affects. The implementation of the model in finite element codes requires a numerical treatment of the constitutive equations with respect to the given interface of the used code. In this paper constitutive equations for the superalloy IN738LC are presented and the implementation in the finite element code ABAQUS with the numerical preparation of the model is described. In order to validate the model calculations were performed for simple uniaxial loading conditions as well as for a complete cross section of a turbine blade under combined thermal and mechanical loading. The achieved results were compared with those of additional calculations by using ABAQUS, including Norton's law, which was already implemented in this code. (orig.) [de

  5. Development of a structure-dependent materials model for complex high-temperature loads: Turbine blades of IN 738 LC

    International Nuclear Information System (INIS)

    1989-01-01

    In the framework of a material research programme of the Federal Ministry for Research and Technology a joint project of 10 institutes has started. It aims at developing new concepts for high-temperature components. A subtask is concerned with the internally cooled turbine blade of IN 738 LC for stationary gas turbines. The envisaged procedure for the development of the design conception and the level of knowledge concerning the influencing parameters of the structure and the mechanical behaviour at high operating temperatures are reported on. (orig.) [de

  6. Tailoring the texture of IN738LC processed by selective laser melting (SLM) by specific scanning strategies

    Energy Technology Data Exchange (ETDEWEB)

    Geiger, Fabian [General Electric Switzerland GmbH – GE Power, CH-5401 Baden (Switzerland); Kunze, Karsten, E-mail: karsten.kunze@scopem.ethz.ch [ETH Zurich, Scientific Center of Optical and Electron Microscopy (ScopeM), CH-8093 Zürich (Switzerland); Etter, Thomas [General Electric Switzerland GmbH – GE Power, CH-5401 Baden (Switzerland)

    2016-04-20

    Selective laser melting (SLM) is an emerging technology of additive manufacturing, which is used to directly produce metallic parts from thin powder layers. This study aims at correlating laser scanning strategies with the resulting textures and corresponding anisotropy of the elastic behavior of bulk materials. Tensile test specimens made of the γ’-containing Ni-base superalloy IN738LC were built with the loading direction oriented either parallel (z-specimens) or perpendicular to the build-up direction (xy-specimens). Their bulk mechanical properties were determined at room temperature and at 850 °C. Specimens were investigated in the ‘as-built’ condition and after recrystallization heat treatment. SEM-based electron backscatter diffraction (EBSD) was applied to measure their crystallographic preferred orientations (texture) and to correlate the anisotropy of Young's modulus with the texture of the material. It is shown that the applied laser scanning strategies allow to tailor the crystallographic texture locally. The possibility to switch from transverse anisotropic to transverse isotropic properties and reverse is demonstrated for triple layered tensile samples. A recrystallization heat treatment reduces the degree of crystallographic texture and thus the elastic anisotropy by abundant annealing twinning. Predictions of Young's modulus calculated from the measured textures compare well with the data from tensile tests.

  7. Cyclic life of superalloy IN738LC under in-phase and out-of-phase thermo-mechanical fatigue loading

    International Nuclear Information System (INIS)

    Chen Hongjun; Wahi, R.P.; Wever, H.

    1995-01-01

    The cyclic life of IN738LC, a widely used nickel base superalloy for blades in stationary gas turbines, was investigated under thermo-mechanical fatigue loading using a temperature variation range of 1023 to 1223 K, with temperature variation rate in the range of 6 to 15 K/min. Simple thermo-mechanical cycles with linear sequences corresponding to in-phase (IP) and out-of-phase (OP) tests were performed. Both the IP and OP tests were carried out at different constant mechanical strain ranges varied between 0.8 to 2.0% and at a constant mechanical strain rate of 10 -5 s -1 . Thermo-mechanical fatigue lives under both test conditions were compared with each other and with those of isothermal LCF tests at a temperature of 1223 K. The results show that the life under thermo-mechanical fatigue is strongly dependent on the nature of the test, i.e. stress controlled or strain controlled. (orig.)

  8. Characterization of a NIMONIC TYPE super alloy

    International Nuclear Information System (INIS)

    Zamora Rangel, L.; Martinez Martinez, E.

    1985-01-01

    Mechanical properties of strength and thermofluence of a NIMONIC type super alloy under thermal treatment was determined. The relationship between microstructure, phases and precipitates was also studied. (author)

  9. Precipitate microstructure evolution in exposed IN738LC superalloy

    Czech Academy of Sciences Publication Activity Database

    Strunz, Pavel; Petrenec, Martin; Gasser, U.; Tobiáš, Jiří; Polák, Jaroslav; Šaroun, Jan

    2014-01-01

    Roč. 589, MAR (2014), s. 462-471 ISSN 0925-8388 R&D Projects: GA ČR(CZ) GAP204/11/1453; GA MŠk(XE) LM2011019 EU Projects: European Commission(XE) 283883 - NMI3-II Institutional support: RVO:68081723 ; RVO:61389005 Keywords : metals * precipation * scanning and transmission electron microscopy * high temperature alloys * neutron scattering Subject RIV: BM - Solid Matter Physics ; Magnetism; JL - Materials Fatigue, Friction Mechanics (UFM-A) Impact factor: 2.999, year: 2014

  10. Measurement of γ'precipitates in nimonic PE16

    International Nuclear Information System (INIS)

    Baker, C.; Lobb, R.C.

    1977-09-01

    γ' precipitates in Nimonic PE16 have been examined using bright and dark field imaging techniques in an electron microscope. The validity of these techniques to determine mean precipitate diameters, precipitate density and volume fraction is discussed. It is concluded that bright field imaging techniques are sufficiently accurate to measure γ' precipitate diameters but it is essential to use dark field imaging techniques to determine γ' precipitate density or volume fraction. (author)

  11. Thermal stability of the superalloys Inconel 625 and Nimonic 86

    International Nuclear Information System (INIS)

    Kohl, H.K.; Peng, K.

    1981-01-01

    The thermal stability of Inconel 625 and Nimonic 86, as received, cold worked (10, 20, and 40%), and solution treated, was investigated in the temperature range 500-900 0 C. The annealing times varied from 0.3 (0.03) to 100 days. Precipitation hardening and recovery (recrystallisation) takes place in cold worked material, beginning after shorter times in cold worked material than in as received material. The temperature interval for precipitation hardening is extended in Nimonic 86, due to cold working, from about 500-600 0 C to about 450-700 0 C. It is possible to suppress or retard the precipitation hardening in solution treated Inconel 625 and Nimonic 86 by fast cooling after solution annealing. Hardness was measured at room temperature with five different loads, so that the parameters k and n from Meyer's-law, and the Brinell hardness number (for F / D 2 = 30) could be determined. The lattice contraction of Inconel 625 due to ageing was investigated with X-ray measurements. The change of intensities of the diffractometer traces due to recovery was also determined. (orig.)

  12. NIMONIC 263 microstructure and surface characterization after laser shock peening

    Directory of Open Access Journals (Sweden)

    P. Drobnjak

    2015-07-01

    Full Text Available The Laser Shock Peening (LSP is applied to the surface of Nimonic 263 alloy. The changes in microstructure and surface topography are observed and analyzed by Scanning Electron Microscopy (SEM, profilometer and microhardness tester. Various laser regimes are chosen which provoke effects of both mechanical and thermo-mechanical treatments of the sample surface. The optimal process parameters, that result in the finest microstructure, smooth and clean surface, are determined. Some wanted and unwanted phases leading to the crack formation are observed.

  13. Ring ductility of irradiated Inconel 706 and Nimonic PE16

    International Nuclear Information System (INIS)

    Huang, F.H.; Fish, R.L.

    1984-01-01

    The tensile ductility of fast neutron-irradiated, precipitation-hardened alloys Inconel 706 and Nimonic PE16 has been observed to be very low for certain test conditions. Explanations for the low ductility behavior have been sought by examination of broken tensile specimens with microscopy and other similar techniques. A ring compression test provides a method of evaluating the ductility of irradiated cladding specimens. Unlike the conventional uniaxial tensile testing in which the tensile specimen is deformed uniformly, the ring specimen is subjected to localized bending where the crack is initiated. The ductility can be estimated through an analysis of the bending of a ring in terms of strain hardening. Ring sections from irradiated, solution-treated Inconel 706 and Nimonic PE16 were compressed in the diametral direction to provide load-deflection records over a wide range of irradiation and test temperatures. Results showed that ductility in both alloys decreased with increasing test temperatures. The poorest ductility was exhibited at different irradiation temperatures in the two alloys - near 550 0 C for PE16 and 460 to 520 0 C for Inconel 706. The ring ductility data indicate that the grain boundary strength is a major factor in controlling the ductility of the PE16 alloy

  14. Segregation to grain boundaries in nimonic PE16 superalloy

    International Nuclear Information System (INIS)

    Nettleship, D.J.; Wild, R.K.

    1990-01-01

    Nimonic PE16 alloy is a nickel-based superalloy containing 34 wt.% iron and 16wt.% chromium with additions of molybdenum, titanium and aluminium. It is used in the fuel assembly of the UK advanced gas-cooled reactors (AGR). This component supports significant loads in service and its mechanical integrity is therefore of paramount importance. Mechanical properties may be influenced by the grain size and grain boundary composition, both of which can themselves alter during service. Scanning Auger microscopy is a well-established method for investigating grain boundaries, and has now been applied to the study of PE16. In order to expose PE16 grain boundary surfaces it is necessary to hydrogen charge samples and fracture by pulling in tension at a slow strain rate within the ultra-high vacuum chamber of the Auger microprobe. A series of casts of nimonic PE16 alloy that have received a range of thermal ageing treatments have been fractured in an intergranular manner and the grain boundary composition determined. Segregation of trace and minority elements, particularly Mo and P, has been detected at grain boundaries. Significant variations between different as-manufactured casts were observed, whilst ageing brought about the growth of chromium-rich particles on the grain boundaries. Ductile fracture in PE16 followed a path through Ti(C, N) particles. Many of these particles incorporated large amounts of sulphur. (author)

  15. Recovery of creep properties of the nickel-base superalloy nimonic 105

    CSIR Research Space (South Africa)

    Girdwood, RB

    1996-01-01

    Full Text Available Uniaxial constant stress creep tests were performed on the wrought nickel-base superalloy Nimonic 105. Entire creep curves were recorded and curve shapes analysed using the Theta Projection Concept. Rejuventive procedures were applied to pre...

  16. Study of Surface Relief Evolution in Cyclically Strained Superalloy IN738LC Using Advanced Experimental Techniques

    Czech Academy of Sciences Publication Activity Database

    Juliš, M.; Kusmič, D.; Pospíšilová, S.; Průša, S.; Obrtlík, Karel; Dluhoš, J.; Podrábský, T.

    2011-01-01

    Roč. 105, S (2011), s. 814-815 ISSN 0009-2770. [Lokálne mechanické vlastnosti 2010. Smolenice, 10.11.2010-12.11.2010] R&D Projects: GA ČR(CZ) GAP107/11/2065 Institutional research plan: CEZ:AV0Z20410507 Keywords : Inconel 738LC * low cycle fatigue * surface relief Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.529, year: 2011

  17. Microstructural study of weld fusion zone of TIG welded IN 738LC nickel-based superalloy

    International Nuclear Information System (INIS)

    Ojo, O.A.; Richards, N.L.; Chaturvedi, M.C.

    2004-01-01

    The weld fusion zone microstructure of a commercial aerospace superalloy IN 738 was examined. Elemental segregation induced interdendritic microconstituents were identified to include terminal solidification product M 3 B 2 and Ni 7 Zr 2 in association with γ-γ' eutectic constituent, which require proper consideration during the development of optimum post weld heat treatment

  18. Evaluation of fatigue properties of HFIR-irradiated nimonic PE-16 at 4300C

    International Nuclear Information System (INIS)

    Grossbeck, M.L.; Liu, K.C.

    1984-01-01

    Nimonic PE-16 was irradiated in the HFIR to 6 to 9 dpa and 560 to 1000 at. ppM He at 430 0 C. Postirradiation fatigue tests revealed a reduction in fatigue life by about a factor of 10 at 430 0 C. In contrast with AISI type 316 stainless steel, no endurance limit was observed. All irradiated specimens exhibited some intergranular fracture with an increasing tendency toward cleavage like intragranular fracture for low strain ranges

  19. Fatigue performance of HFIR-irradiated Nimonic PE-16 at 4300C

    International Nuclear Information System (INIS)

    Grossbeck, M.L.; Liu, K.C.

    1983-01-01

    Nimonic PE-16 was irradiated in the HFIR to 6 to 9 dpa and 560 to 1000 at. ppM He at 430 0 C. Postirradiation fatigue tests revealed a reduction in fatigue life by about a factor of 10 at 430 0 C. In contrast to AISI type 316 stainless steel, no endurance limit was observed. All irradiated specimens exhibited some intergranular fracture with an increasing tendency toward cleavage-like intragranular fracture for low strain ranges

  20. Trim cut machining and surface integrity analysis of Nimonic 80A alloy using wire cut EDM

    Directory of Open Access Journals (Sweden)

    Amitesh Goswami

    2017-02-01

    Full Text Available This present work deals with the features of trim cut wire EDM machining of Nimonic 80A in terms of machining parameters, to predict material removal rate (MRR, surface roughness (Ra, wire wear ratio (WWR and microstructure analysis. Trim cut is performed after rough cut to remove the rough layer deposited after machining due to melting and re-solidification of the eroded metal from workpiece as well as from wire electrode. Taguchi’s design of experiments methodology has been used for planning and designing the experiments. The relative significance of various factors has also been evaluated and analyzed using ANOVA. The results clearly indicate trim cut potential for high surface finish compared to rough cut machining.

  1. Microstructural investigation of variations in the proof strength of Nimonic PE16

    International Nuclear Information System (INIS)

    Riley, B.F.; Wilson, E.G.; Jones, A.R.

    1987-01-01

    Nimonic PE16 shows a correlation of stress rupture behaviour after irradiation with proof strength. Proof testing of material from bars from several casts yielded a relationship (Hall-Petch) between the peak-aged proof stress and grain size -1/2 but the scatter in proof stress values at a given grain size merited further microstructural study. Transmission electron microscopy revealed that high proof stress material contained dislocation densities consistent with material which had received 1 to 2% cold work, verified by examination of lightly prestrained tensile specimens. Ageing to peak strength induced partial recovery but some variability in proof stress remained. Variations in γ' size and composition having been eliminated, the scatter in proof stress values was attributed to variable cold work induced by the commercial bar straightening process. (Author)

  2. Microstructural basis and crack growth theories for post-irradiation ductility loss in Nimonic PE16

    International Nuclear Information System (INIS)

    Chang, A.L.

    1982-01-01

    A study has been carried out to investigate the degradation of postirradiation ductility at reactor temperatures in Nimonic PE16, a Fe-Cr-Ni-based precipitation-hardened superalloy. Fractographic and microstructural investigations show that the grain matrix is capable of deformation and does not limit the postirradiation tensile ductility. Grain-boundary helium bubbles formed during neutron irradiation seem to be crack nucleation sites under stress. Growth and coalescence of these microcracks under stress lead to intergranular fracture. A rigid-grain fracture model is shown to be able to correlate the observed microstructures with most features of the mechanical properties, except the strain rate dependence of the ductility. By incorporating the interactions between diffusion and plastic deformation, a plastic-grain fracture model has been developed which can explain all postirradiation tensile ductility data quantitatively. 13 references

  3. Damage structure in Nimonic PE16 alloy ion bombarded to high doses and gas levels

    International Nuclear Information System (INIS)

    Farrell, K.; Packan, N.H.

    1981-01-01

    The Nimonic PE16 alloy in solution-treated-and-aged condition was bombarded simultaneously with nickel ions and α and deuteron beams at 625 0 C to doses of 80 to 313 dpa at He/dpa = 10 and D/dpa = 25. Microstructural changes consisted of the introduction of dislocations and of cavities, and the redistribuion of γ' precipitates to these defects. Cavitational swelling remained below 1%. Cavities were represented by several distinct size classes, the smaller ones believed to be gas bubbles, and some larger ones associated with preferred growth of precipitate. Formation of bubbles at grain boundaries, and large cavities at incoherent twins intensified the possibility of mechanical separation of interfaces under high-gas irradiation conditions

  4. An EBSD Evaluation of the Microstructure of Crept Nimonic 101 for the Validation of a Polycrystal-Plasticity Model

    Science.gov (United States)

    Reschka, S.; Munk, L.; Wriggers, P.; Maier, H. J.

    2017-12-01

    Nimonic 101 is one of the early nickel-based superalloys developed for the use in gas turbines. In such environments, the material is exposed to a combination of both high temperatures and mechanical loads for a long duration. Hence, thermal creep is of the utmost concern as it often limits service life. This study focuses on creep tests, carried out on Nimonic 101 at different temperatures under a constant tensile load of 735 MPa. To characterize the microstructural evolution, electron backscatter diffraction (EBSD) measurements were employed before and after loading. At higher temperatures, a significant change of the microstructure was observed. The grains elongated and aligned their orientation along the load axis. In parallel, a crystal plasticity material model has been set up in the classical large deformation framework. Modeling results are compared to the acquired EBSD data.

  5. Improvement of surface integrity of Nimonic C 263 super alloy produced by WEDM through various post-processing techniques

    Czech Academy of Sciences Publication Activity Database

    Mandal, A.; Dixit, A. R.; Chattopadhyaya, S.; Paramanik, A.; Hloch, Sergej; Królczyk, G.

    2017-01-01

    Roč. 93, 1-4 (2017), s. 433-443 ISSN 0268-3768 Institutional support: RVO:68145535 Keywords : surface integrity * wire-EDM * Nimonic C-263 * multi-cut * recast layer Subject RIV: JQ - Machines ; Tools OBOR OECD: Mechanical engineering Impact factor: 2.209, year: 2016 https://link.springer.com/article/10.1007/s00170-017-9993-x

  6. Improvement of surface integrity of Nimonic C 263 super alloy produced by WEDM through various post-processing techniques

    Czech Academy of Sciences Publication Activity Database

    Mandal, A.; Dixit, A. R.; Chattopadhyaya, S.; Paramanik, A.; Hloch, Sergej; Królczyk, G.

    2017-01-01

    Roč. 93, 1-4 (2017), s. 433-443 ISSN 0268-3768 Institutional support: RVO:68145535 Keywords : surface integrity * wire-EDM * Nimonic C-263 * multi-cut * recast layer Subject RIV: JQ - Machines ; Tools OBOR OECD: Mechanical engineering Impact factor: 2.209, year: 2016 https://link.springer.com/ article /10.1007/s00170-017-9993-x

  7. The role of particle ripening on the creep acceleration of Nimonic 263 superalloy

    Directory of Open Access Journals (Sweden)

    Angella Giuliano

    2014-01-01

    Full Text Available Physically based constitutive equations need to incorporate the most relevant microstructural features of materials to adequately describe their mechanical behaviour. To accurately model the creep behaviour of precipitation hardened alloys, the value and the evolution of strengthening particle size are important parameters to be taken into account. In the present work, creep tests have been run on virgin and overaged (up to 3500 h at 800 ∘C Nimonic 263, a polycrystalline nickel base superalloy used for combustion chambers of gas turbines. The experimental results suggest that the reinforcing particle evolution is not the main reason for the creep acceleration that seems to be better described by a strain correlated damage, such as the accumulation of mobile dislocations or the grain boundary cavitation. The coarsened microstructure, obtained by overageing the alloy at high temperature before creep testing, mainly influences the initial stage of the creep, resulting in a higher minimum creep rate and a corresponding reduction of the creep resistance.

  8. Effect of microstructure on elevated temperature LCF behaviour of nimonic PE16 superalloy

    International Nuclear Information System (INIS)

    Valsan, M.; Bhanu Sankara Rao, K.; Mannan, S.L.

    1989-01-01

    The influence of microstructure on elevated temperature low cycle fatigue (LCF) behaviour of Nimonic PE16 superalloy has been studied. Samples with the following three different prior microstructures were chosen for testing: (A) a fine grain structure, free from carbides and γ'(1313K/4h); (B) microstructure with intra and intergranular M 23 C 6 and uniform distribution of spherical and peak aged γ' of 18 nm diameter (1313K/4h + 1073K/2h + 973K/16h); and (C) microstructure with predominantly intergranular MC and uniform distribution of coarse γ' of 35 nm diameter (1313K/4h+1173K/1h+1023K/8h). Total strain controlled LCF tests were carried out on all the three microstructures at 823 and 923K and at a constant strain rate of 3.2x10 -3 s -1 over strain amplitudes ranging from ±0.25 ±1.00 per cent. (author). 54 refs., 17 figs., 3 tabs

  9. Electron microscopy observations of helium bubble-void transition effects in nimonic PE16 alloys

    International Nuclear Information System (INIS)

    Mazey, D.J.; Nelson, R.S.

    1980-01-01

    High-nickel alloys based on the Nimonic PE16 composition have been injected at temperatures of 525 0 C and 625 0 C with 1000 ppm helium to produce a high gas-bubble concentration and subsequently irradiated with 36 MeV nickel ions. Extensive heterogeneous nucleation of bubbles is observed on faulted interstitial loops and dislocations. Evidence is found in standard PE16 alloy for bimodal bubble plus void distributions which persist during nickel-ion irradiation to 30 and 60 dpa at 625 0 C and result in a low void volume swelling of approximately 1%. The observations can be correlated with the critical bubble/void transition radius which is calculated from theory to be approximately 4.4 nm. Pre-injection of helium into a 'matrix' PE16 (low Si, Ti and Al) alloy produced an initial bubble population whose average size was above the calculated transition radius such that all bubbles eventually grew as voids during subsequent nickel-ion irradiation up to 60 dpa at 625 0 C where the void volume swelling reached approximately 12%. The observations are discussed briefly and related to theoretical predictions of the bubble/void transition radius. (author)

  10. Characterization of defects and nanostructural alterations in the Nimonic 80A superalloy by using Transmission Electron Microscopy

    International Nuclear Information System (INIS)

    Guillen Giron, Teodolito; Leon Salazar, Jose Luis

    2015-01-01

    TEM (Transmission Electron Microscopy) probes are analyzed in aeronautical applications. Intercrystalline defects present in the Nimonic 80A superalloy are studied after being thermally treated and then subjecting the specimens to cyclic stresses. The TEM test specimens are pre-tested under high frequency (1 000 Hz and 20 000 Hz) fatigue at the University of Siegen in Germany simulating the working conditions of this alloy in aircraft turbines or other types of aeronautical applications. The mechanical stress has generated many deformations and nanometric defects in this material, evidenced in the dislocations. Defects are observed using very powerful microscopy techniques such as TEM. The results are obtained from the TEM analysis and have revealed characteristic precipitates in the Nimonic 80A sample when subjected to thermal treatments. The alloy has evidenced the formation of dislocations resulting from the mechanical stresses of the specimens. The influence of rainfall is evidenced in the mechanism of formation, grouping and movement of the dislocations in the microstructure of the samples used. (author) [es

  11. Effect of long time service exposure on microstructure and mechanical properties of gas turbine vanes made of IN939 alloy

    International Nuclear Information System (INIS)

    Jahangiri, M.R.; Abedini, M.

    2014-01-01

    Highlights: • Microstructure of service-exposed turbine vanes made of IN939 was investigated. • Mechanical properties of service-exposed alloy were also investigated. • Formation of M 23 C 6 films on GBs and degeneration of MCs are microstructural changes. • Despite its thermodynamic favorability, σ phase is not observed in microstructure. • Microstructural changes lead to a loss in tensile ductility and creep life. - Abstract: In the present study, the effects of long-term service exposure have been investigated on microstructure and mechanical properties of gas turbine vanes made of IN939 superalloy. The major microstructural changes for the investigated service-exposed vanes include the formation of continuous grain boundary carbides and the transformation (degeneration) of MC carbides located at the grain boundaries. The brittle σ phase, which is predicted to be stable on the basis of thermodynamic calculations, is not observed in the microstructure of service-exposed vanes. The microstructural changes during service lead to a loss in room temperature ductility as well as in creep properties of the alloy

  12. Effect of small cold forming on the creep behaviour of gas turbine blades made of Nimonic 90

    International Nuclear Information System (INIS)

    Keienburg, K.H.; Krueger, H.; Pickert, U.; Bautz, G.

    1987-01-01

    In order to obtain information on the material behaviour of Nimonic 90 with and without cold forming at the main temperature of use of 560deg C for large gas turbine blades, creep and relaxation samples were taken from the large volume foot of a gas turbine blade, part of which were tensioned by 3% cold in a tensile test machine. The selected cold forming was obtained as the upper limit from DMS measurements on a gas turbine blade when aligning. The negative effect of cold forming on the creep behaviour known from the literature for other γ hardened nickel base alloys was confirmed. The grain (matrix) is strengthened and the grain boundary is simultaneously weakened by cold forming. The material is also sensitized, so that fine separation occurs in the grain at the sliding bands and at the grain boundaries. Both circumstances contribute to the worsening of the creep behaviour, significantly for stresses below the technical elastic limit in the cold formed state. It follows, relative to large gas turbine blades, that: 1) Aligning operations must be restricted to the absolute minimum necessary and should be avoided completely if possible. 2) Aligned blades should be subjected to renewed solution annealing and separation hardening. 3.) Blades deformed in operation should also be subjected to renewed complete heat treatment. (orig.) [de

  13. Effects of aging and sheet thickness on the room temperature deformation behavior and in-plane anisotropy of cold rolled and solution treated Nimonic C-263 alloy sheet

    Energy Technology Data Exchange (ETDEWEB)

    Ankamma, Kandula; Chandra Mohan Reddy, Gangireddy [Mahatma Ghandi Institute of Technology, Hyderabad (India). Mechanical Engineering Dept.; Singh, Ashok Kumar; Prasad, Konduri Satya [Defence Research and Development Organisation (DRDO), Hyderabad (India). Defence Metallurgical Research Lab.; Komaraiah, Methuku [Malla Reddy College of Engineering and Technology, Secunderabad (India); Eswara Prasad, Namburi [Regional Centre for Military Airworthiness (Materials), Hyderabad (India)

    2011-10-15

    The deformation behavior under uni-axial tensile loading is investigated and reported in the case of cold rolled Nimonic C-263 alloy sheet products of different thicknesses (0.5 mm and 1 mm) in the solution treated and aged conditions. The studies conducted include (i) Microstructure, (ii) X-ray diffraction, (iii) Texture and (iv) Tensile properties and inplane anisotropy in the yield behavior (both tensile yield strength and ultimate tensile strength as well as ductility). The results of the present study showed that despite the presence of weak crystallographic texture in this crystal symmetric material, the degrees of in-plane anisotropy in strength as well as plastic deformation properties are found to be significant in both solution treated and aged conditions, thus having significant technological relevance for both further processing and design purposes. Further, the influence of aging and sheet thickness on the tensile deformation behaviour is also found to be considerable. A brief discussion on the technological implications of these results is also included. (orig.)

  14. Analysis and description of the long-term creep behaviour of high-temperature gas turbine materials

    International Nuclear Information System (INIS)

    Bartsch, H.

    1985-01-01

    On a series of standard high-temperature gas turbine materials, creep tests were accomplished with the aim to obtain improved data on the long-term creep behaviour. The tests were carried out in the range of the main application temperatures of the materials and in the range of low stresses and elongations similar to operation conditions. They lasted about 5000 to 16000 h at maximum. At all important temperatures additional annealing tests lasting up to about 10000 h were carried out for the determination of a material-induced structure contraction. Thermal tension tests were effected for the description of elastoplastic short-time behaviour. As typical selection of materials the nickel investment casting alloys IN-738 LC, IN-939 and Udimet 500 for industrial turbine blades, IN-100 for aviation turbine blades and IN-713 C for integrally cast wheels of exhaust gas turbochargers were investigated, and also the nickel forge alloy Inconel 718 for industrial and aviation turbine disks and Nimonic 101 for industrial turbine blades and finally the cobalt alloy FSC 414 for guide blades and heat accumulation segments of industrial gas turbines. The creep tests were started on long-period individual creep testing machines with high strain measuring accuracy and economically continued on long-period multispecimen creep testing machines with long duration of test. The test results of this mixed test method were first subjected to a conventional evaluation in logarithmic time yield and creep diagrams which besides creep strength curves provided creep stress limit curves down to 0.2% residual strain. (orig./MM) [de

  15. Creep equations for gas turbine materials

    International Nuclear Information System (INIS)

    Kloos, K.H.; Granacher, J.; Preussler, T.

    1988-01-01

    The long-term high-temperature deformation behaviour of typical gas turbine materials can be described on the basis of a differentiated evaluation which takes the results from thermal tension tests, short-term creep tests with continuous extension measurement, long-term creep tests with discontinuous extension measurement as well as annealing tests with contraction measurement into account. By this, especially the 'negative creeping' can be controlled. Equations were developed for individual materials of the type IN-738 LC, IN-939, IN-100 and FSX-414, which describe the high-temperature deformation behaviour with consideration to the primary and secondary creeping and partly the tertiary creeping. The equations are valid in the entire application-relevant range, i.e. up to 100 000 h in the case of industrial turbine materials. (orig.) [de

  16. Multivariate analysis of dietary patterns in 939 Swiss adults: sociodemographic parameters and alcohol consumption profiles.

    Science.gov (United States)

    Gex-Fabry, M; Raymond, L; Jeanneret, O

    1988-09-01

    A dietary survey of 939 Swiss adults, randomly selected from the population of Geneva and its surrounding communities, was performed according to the history method. A factor analysis, using average weekly intakes for 33 food variables, reveals three principal components of the diet: satiating capacity, healthfulness and culinary complexity. These characteristics, together with the energy content of the diet, were analysed for differences according to sex, age, relative weight index, birthplace, marital status and occupation. All of these sociodemographic variables influence some dimension of dietary habits. Alcohol consumption is positively associated with satiating, protein rich diets, but energy intake from foods does not significantly differ between various groups of abstainers and drinkers. Although the energy contribution of alcoholic beverages is globally additive, we suggest that cultural and societal norms may modulate the relationship of alcohol and diet.

  17. Numerical description of creep of highly creep resistant alloys

    International Nuclear Information System (INIS)

    Preussler, T.

    1991-01-01

    Fatigue tests have been performed with a series of highly creep resistant materials for gas turbines and related applications for gaining better creep data up to long-term behaviour. The investigations were performed with selected individual materials in the area of the main applications down to strains and stresses relevant to design, and have attained trial durations of 25000 to 60000 h. In continuing former research, creep equations for a selection of characterizing individual materials have been improved and partly newly developed on the basis of a differentiated evaluation. Concerning the single materials, there are: one melt each of the materials IN-738 LC, IN-939, IN-100, FSX-414 and Inconel 617. The applied differentiated evaluation is based on the elastoplastical behaviour from the hot-drawing test, the creep behaviour from the non interrupted or the interrupted fatigue test, and the contraction behaviour from the annealing test. The creep equations developed describe the high temperature deformation behaviour taking into account primary, secondary and partly the tertiary creep dependent of temperature, stress and time. These equations are valid for the whole application area of the respective material. (orig./MM) [de

  18. Effect of elastic interphase strains on extinction in aging nimonic type alloys

    International Nuclear Information System (INIS)

    Gitgarts, M.I.; Ivashin, V.V.

    1977-01-01

    The effect of νsup(')-phase separation processes on the variation of (3) CuKsub(α) diffraction line integral intensity in KhN67VMTYu alloy ageing has been investigated, the alloy being characterized by various degrees of volumetric inconsistency between the separation phase and matrix. The ageing of KhN67VMTYu alloy, in which the separation of the νsup(')-phase does not cause interphase strains, is not accompanied by abatement of extinction: the diffraction line intensity is practically the same for both aged and tempered specimens

  19. Thermal-mechanical fatigue of high temperature structural materials

    Science.gov (United States)

    Renauld, Mark Leo

    Experimental and analytical methods were developed to address the effect of thermal-mechanical strain cycling on high temperature structural materials under uniaxial and biaxial stress states. Two materials were used in the investigation, a nickel-base superalloy of low ductility, IN-738LC and a high ductility material, 316 stainless steel. A uniaxial life prediction model for the IN-738LC material was based on tensile hysteresis energy measured in stabilized, mid-life hysteresis loops. Hold-time effects and temperature cycling were incorporated in the hysteresis energy approach. Crack growth analysis was also included in the model to predict the number of TMF cycles to initiate and grow a fatigue crack through the coating. The nickel-base superalloy, IN-738LC, was primarily tested in out-of-phase (OP) TMF with a temperature range from 482-871sp°C (900-1600sp°F) under continuous and compressive hold-time cycling. IN-738LC fatigue specimens were coated either with an aluminide, NiCoCrAlHfSi overlay or CoNiCrAlY overlay coating on the outer surface of the specimen. Metallurgical failure analysis via optical and scanning electron microscopy, was used to characterize failure behavior of both substrate and coating materials. Type 316 SS was subjected to continuous biaxial strain cycling with an in-phase (IP) TMF loading and a temperature range from 399-621sp°C (750-1150sp°F). As a result, a biaxial TMF life prediction model was proposed on the basis of an extended isothermal fatigue model. The model incorporates a frequency effect and phase factors to assess the different damage mechanisms observed during TMF loading. The model was also applied to biaxial TMF data generated on uncoated IN-738LC.

  20. Influence of different etchants on the representation of microstructures in nickel alloys; Einfluss verschiedener Aetzmittel auf die Gefuegedarstellung in Nickellegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Speicher, Magdalena; Scheck, Rudi; Maile, Karl [Stuttgart Univ. (Germany). Materialpruefungsanstalt

    2016-04-15

    This work presents a comparison of selected nickel alloys of the same condition which were treated by means of specifically chosen etching techniques. Microstructures on microscope images of wrought Alloy 617, a casting variant of Alloy 625, a polycrystalline casting alloy IN-738 LC, as well as of a monocrystalline superalloy CM 247 LC SX, respectively, are juxtaposed and evaluated. This approach allows for a comprehensive optical microscopy characterization of the characteristic microstructural features.

  1. Prospects for the domestic production of large-sized cast blades and vanes for industrial gas turbines

    Science.gov (United States)

    Kazanskiy, D. A.; Grin, E. A.; Klimov, A. N.; Berestevich, A. I.

    2017-10-01

    Russian experience in the production of large-sized cast blades and vanes for industrial gas turbines is analyzed for the past decades. It is noted that the production of small- and medium-sized blades and vanes made of Russian alloys using technologies for aviation, marine, and gas-pumping turbines cannot be scaled for industrial gas turbines. It is shown that, in order to provide manufacturability under large-scale casting from domestic nickel alloys, it is necessary to solve complex problems in changing their chemical composition, to develop new casting technologies and to optimize the heat treatment modes. An experience of PAO NPO Saturn in manufacturing the blades and vanes made of ChS88U-VI and IN738-LC foundry nickel alloys for the turbines of the GTE-110 gas turbine unit is considered in detail. Potentialities for achieving adopted target parameters for the mechanical properties of working blades cast from ChS88UM-VI modified alloy are established. For the blades made of IN738-LC alloy manufactured using the existing foundry technology, a complete compliance with the requirements of normative and technical documentation has been established. Currently, in Russia, the basis of the fleet of gas turbine plants is composed by foreign turbines, and, for the implementation of the import substitution program, one can use the positive experience of PAO NPO Saturn in casting blades from IN738-LC alloy based on a reverse engineering technique. A preliminary complex of studies of the original manufacturer's blades should be carried out, involving, first of all, the determination of geometric size using modern measurement methods as well as the studies on the chemical compositions of the used materials (base metal and protective coatings). Further, verifying the constructed calculation models based on the obtained data, one could choose available domestic materials that would meet the operating conditions of the blades according to their heat resistance and corrosion

  2. Processing of SiO2 protective layer using HMDS precursor by combustion CVD.

    Science.gov (United States)

    Park, Kyoung-Soo; Kim, Youngman

    2011-08-01

    Hexamethyldisilazane (HMDS, [(CH3)3Si]2NH) was used as a precursor to form SiO2 protective coatings on IN738LC alloys by combustion chemical vapor deposition (CCVD). SEM and XPS showed that the processed coatings were composed mainly of SiO2. The amount of HMDS had the largest effect on the size of the SiO2 agglomerates and the thickness of the deposited coatings. The specimens coated with SiO2 using the 0.05 mol/l HMDS solution showed a significantly higher temperature oxidation resistance than those deposited under other conditions.

  3. Microstructural causes of negative creep in cast superalloys

    International Nuclear Information System (INIS)

    Frank, G.

    1990-01-01

    The dissertation examines by means of microstructural investigations and modelling calculations two types of superalloys: the nickel-base cast alloy IN 738 LC (γ'-hardened, containing MC and M 23 C 6 carbides), and the cobalt-base cast alloy FSX 414 (containing M 23 C 6 carbides, solid solution-hardened). The task was to determine the causes of microstructural volume contraction, in order to improve and facilitate explanation and extrapolation of the materials' long-term behaviour at high temperatures, and to derive if possible information on appropriate measures preventing negative creep, which may lead to critical damage of bolted joints, for instance. (orig./MM) [de

  4. Cyclic plastic response of nickel-based superalloy at room and at elevated temperatures

    International Nuclear Information System (INIS)

    Polak, Jaroslav; Petrenec, Martin; Chlupova, Alice; Tobias, Jiri; Petras, Roman

    2015-01-01

    Nickel-based cast IN 738LC superalloy has been cycled at increasing strain amplitudes at room temperature and at 800 C. Hysteresis loops were analyzed using general statistical theory of the hysteresis loop. Dislocation structures of specimens cycled at these two temperatures were studied. They revealed localization of the cyclic plastic strain in the thin bands which are rich in dislocations. The analysis of the loop shapes yields effective stresses of the matrix and of the precipitates and the probability density function of the critical internal stresses at both temperatures. It allows to find the sources of the high cyclic stress.

  5. Low temperature gaseous nitriding of Ni based superalloys

    DEFF Research Database (Denmark)

    Eliasen, K. M.; Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2010-01-01

    In the present work the nitriding response of selected Ni based superalloys at low temperatures is addressed. The alloys investigated are nimonic series nos. 80, 90, 95 and 100 and nichrome (Ni/Cr......In the present work the nitriding response of selected Ni based superalloys at low temperatures is addressed. The alloys investigated are nimonic series nos. 80, 90, 95 and 100 and nichrome (Ni/Cr...

  6. Development of a structure-dependent material model for complex, high-temperature environments and stresses. Example: turbine blades, turbine discs

    International Nuclear Information System (INIS)

    Schubert, F.

    1988-01-01

    For the optimum use of new high-temperature superalloys for turbine discs and blades, it is necessary to develop new design concepts which, on the one hand, permit a quantitative allocation of the structural characteristics to the deformation behaviour and damage mechanisms and, on the other hand, take into account the real course of stress. It is planned to use PM-Udinet 700 as material for turbine discs and IN 738 LC with supplementary tests of IN 100 for turbine blades. For turbine discs, a probabilistic model is developed, for turbine blades, cooled at the interior, first a deterministic model is developed and then a probabilistic model is prepared. The concept for the development of the models is dealt with in detail. The project started in April 1987, therefore only first investigation results can be reported. (orig.) [de

  7. Development and evaluation of high temperature materials for power plant

    International Nuclear Information System (INIS)

    Nickel, H.; Schubert, F.

    1992-01-01

    The development of high temperature materials requires the evaluation of the interaction of microstructure and mechanical properties, the implementation of the microstructural aspects in the constitutive equations for the analysis of loads in a high temperature component and verification of the materials reactions. In this way the full potential of materials properties can be better used. This fundamental method is the basis for the formulation of the structural design code KTA 3221 'Metallic HTR Components'. The method of 'design by analysis' is also activated for large internally cooled turbine blades for stationary gas turbines in combined cycle power plants. This kind of exploratory analysis during the dimensioning procedure are discussed with two examples: He/He-heat exchanger produced of NiCr23Co12Mo (Alloy 617) and turbine blades made of superalloys (e.g. IN 738 LC). (author)

  8. Steady State Structural Analysis of High Pressure Gas Turbine Blade using Finite Element Analysis

    Science.gov (United States)

    Mazarbhuiya, Hussain Mahamed Sahed Mostafa; Murari Pandey, Krishna

    2017-08-01

    In gas turbines the major portion of performance dependency lies upon turbine blade design. Turbine blades experience very high centrifugal, axial and tangential force during power generation. While withstanding these forces blades undergo elongation. Different methods have proposed for better enhancement of the mechanical properties of blade to withstand in extreme condition. Present paper describes the stress and elongation for blades having properties of different materials. Steady state structural analysis have performed in the present work for different materials (In 625, In 718, In 738, In 738 LC, MAR M246, Ni-Cr, Ti-alloy, Ti-Al, Ti-T6, U500). Remarkable finding is that the root of the blade is subjected to maximum stress for all blade materials and the blade made of MAR M246 has less stress and deformation among all other blade materials which can be selected as a suitable material for gas turbine blade.

  9. Fatigue lifespan of a mobile blade gas turbine with ceramic coating; Vida util por fatiga de un alabe movil de turbina de gas con recubrimiento ceramico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Illescas, Rafael; Z. Mazur Czerwiec, Zdzislaw; Islas Mungarro, Ricardo [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: rgi@iie.org.mx; mazur@iie.org.mx; rick_iie@terra.com.mx

    2010-11-15

    Fatigue analysis of a gas turbine moving blade made of IN738LC was carried out in order to evaluate useful life time. The life estimation was done from a previous 3D linear finite element analysis where thermal and mechanical stress calculation at high temperatures was done during steady and transient state i.e. normal start ups and shutdowns. Several load histories with different stresses and strains in the blade were used for different cooling conditions including a thermal barrier coating in comparison with to simple blade without such coating. The important effect of high temperatures on the blade material and stress calculations is shown. The analysis is focused on two different critical zones in the blade: the leading edge at the middle of the height and a cooling channel surface, where high stresses were found in numerical analysis as well as in reality. Finally, the benefit of the presence of a thermal barrier coating in the blade life is shown. [Spanish] Se realizo el analisis de fatiga de un alabe movil de turbina de gas fabricado de IN738LC a fin de evaluar su vida util. La estimacion de vida fue realizada a partir de simulaciones lineales de esfuerzos termomecanicos por elemento finito en 3D a altas temperaturas y durante el arranque y paro normal. Se utilizaron diversos historiales de carga, esfuerzos y deformaciones del alabe para diferentes configuraciones de enfriamiento incluyendo el recubrimiento ceramico tipo barrera termica en comparacion con los resultados sin incluir dicho recubrimiento. Se presenta el efecto importante de las temperaturas elevadas en las propiedades de fatiga del material del alabe y en sus esfuerzos. El analisis se centra en dos puntos de interes identificados como criticos: borde de entrada y un canal de enfriamiento, en donde esfuerzos elevados fueron encontrados tanto numericamente como en la realidad. Finalmente se muestra el beneficio del recubrimiento tipo barrera termica en la vida del alabe.

  10. Strength and structure during hot deformation of nickel-base superalloys

    International Nuclear Information System (INIS)

    Ribeiro, N.D.; Sellars, C.M.

    1984-01-01

    The effect of deformational variables on the flow stress and microstructure developed by plane strain compression testing and experimental rolling of three otherwise well characterized nickel-base super alloys, Nimonic 80A, Nimonic 90 and Waspaloy are presented. Rolled or tested samples were sectioned longitudinally at mid-width and were prepared for optical metallography. X-ray analysis of particles observed in several samples was carried out on polished and lightly etehed surfaces using a diffractometer with CoKα radiation. For other samples, energy dispersive x-ray analysis was also carried out in a scanning microscope. (E.G.) [pt

  11. A Preliminary Field Test of an Employee Work Passion Model

    Science.gov (United States)

    Zigarmi, Drea; Nimon, Kim; Houson, Dobie; Witt, David; Diehl, Jim

    2011-01-01

    Four dimensions of a process model for the formulation of employee work passion, derived from Zigarmi, Nimon, Houson, Witt, and Diehl (2009), were tested in a field setting. A total of 447 employees completed questionnaires that assessed the internal elements of the model in a corporate work environment. Data from the measurements of work affect,…

  12. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana. K Ankamma. Articles written in Sadhana. Volume 36 Issue 2 April 2011 pp 223-249. In-plane anisotropy in tensile deformation and its influence on the drawability of Nimonic C–263 alloy sheets · K Ankamma D V V Satyanarayana G Chandramohan Reddy M Komaraiah N Eswara Prasad.

  13. G Chandramohan Reddy

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana. G Chandramohan Reddy. Articles written in Sadhana. Volume 36 Issue 2 April 2011 pp 223-249. In-plane anisotropy in tensile deformation and its influence on the drawability of Nimonic C–263 alloy sheets · K Ankamma D V V Satyanarayana G Chandramohan Reddy M Komaraiah N Eswara ...

  14. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana. M Komaraiah. Articles written in Sadhana. Volume 36 Issue 2 April 2011 pp 223-249. In-plane anisotropy in tensile deformation and its influence on the drawability of Nimonic C–263 alloy sheets · K Ankamma D V V Satyanarayana G Chandramohan Reddy M Komaraiah N Eswara Prasad.

  15. Patrika 2008.P65

    Indian Academy of Sciences (India)

    Latha

    2008-09-09

    Sep 9, 2008 ... at different altitude levels, with specific focus on the. Indian mainland ..... approaches to counter malaria; HIV – the enigmatic. Houdini ... biosynthesis; telomeres; vaccines; internet servers for ..... produced, in Nimonic alloy PE16, through a variety .... of immunosuppressive anti-idiotype antibodies in the latter.

  16. Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Nimonic alloys are Ni-base superalloys used for several high temperature applications, notable among them are the components in space vehicles, rocket engines, submarines, nuclear reactors, chemical processing vessels and heat exchange tubing as they exhibit excellent mechanical strength and creep resistance at ...

  17. Life prediction methodology for thermal-mechanical fatigue and elevated temperature creep design

    Science.gov (United States)

    Annigeri, Ravindra

    Nickel-based superalloys are used for hot section components of gas turbine engines. Life prediction techniques are necessary to assess service damage in superalloy components resulting from thermal-mechanical fatigue (TMF) and elevated temperature creep. A new TMF life model based on continuum damage mechanics has been developed and applied to IN 738 LC substrate material with and without coating. The model also characterizes TMF failure in bulk NiCoCrAlY overlay and NiAl aluminide coatings. The inputs to the TMF life model are mechanical strain range, hold time, peak cycle temperatures and maximum stress measured from the stabilized or mid-life hysteresis loops. A viscoplastic model is used to predict the stress-strain hysteresis loops. A flow rule used in the viscoplastic model characterizes the inelastic strain rate as a function of the applied stress and a set of three internal stress variables known as back stress, drag stress and limit stress. Test results show that the viscoplastic model can reasonably predict time-dependent stress-strain response of the coated material and stress relaxation during hold times. In addition to the TMF life prediction methodology, a model has been developed to characterize the uniaxial and multiaxial creep behavior. An effective stress defined as the applied stress minus the back stress is used to characterize the creep recovery and primary creep behavior. The back stress has terms representing strain hardening, dynamic recovery and thermal recovery. Whenever the back stress is greater than the applied stress, the model predicts a negative creep rate observed during multiple stress and multiple temperature cyclic tests. The model also predicted the rupture time and the remaining life that are important for life assessment. The model has been applied to IN 738 LC, Mar-M247, bulk NiCoCrAlY overlay coating and 316 austenitic stainless steel. The proposed model predicts creep response with a reasonable accuracy for wide range of

  18. Application of a multi-component mean field model to the coarsening behaviour of a nickel-based superalloy

    International Nuclear Information System (INIS)

    Anderson, M.J.; Rowe, A.; Wells, J.; Basoalto, H.C.

    2016-01-01

    A multi-component mean field model has been applied to predict the particle evolution of the γ′ particles in the nickel based superalloy IN738LC, capturing the transition from an initial multimodal particle distribution towards a unimodal distribution. Experiments have been performed to measure the coarsening behaviour during isothermal heat treatments using quantitative analysis of micrographs. The three dimensional size of the γ′ particles has been approximated for use in simulation. A coupled thermodynamic/mean field modelling framework is presented and applied to describe the particle size evolution. A robust numerical implementation of the model is detailed that makes use of surrogate models to capture the thermodynamics. Different descriptions of the particle growth rate of non-dilute particle systems have been explored. A numerical investigation of the influence of scatter in chemical composition upon the particle size distribution evolution has been carried out. It is shown how the tolerance in chemical composition of a given alloy can impact particle coarsening behaviour. Such predictive capability is of interest in understanding variation in component performance and the refinement of chemical composition tolerances. It has been found that the inclusion of misfit strain within the current model formulation does not have a significant affect upon predicted long term particle coarsening behaviour. Model predictions show good agreement with experimental data. In particular, the model predicts a reduced growth rate of the mean particle size during the transition from bimodal to unimodal distributions.

  19. New Mechanistic Models of Long Term Evolution of Microstructure and Mechanical Properties of Nickel Based Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kruzic, Jamie J. [Oregon State Univ., Corvallis, OR (United States); Evans, T. Matthew [Oregon State Univ., Corvallis, OR (United States); Greaney, P. Alex [Univ. of California, Riverside, CA (United States)

    2018-05-15

    The report describes the development of a discrete element method (DEM) based modeling approach to quantitatively predict deformation and failure of typical nickel based superalloys. A series of experimental data, including microstructure and mechanical property characterization at 600°C, was collected for a relatively simple, model solid solution Ni-20Cr alloy (Nimonic 75) to determine inputs for the model and provide data for model validation. Nimonic 75 was considered ideal for this study because it is a certified tensile and creep reference material. A series of new DEM modeling approaches were developed to capture the complexity of metal deformation, including cubic elastic anisotropy and plastic deformation both with and without strain hardening. Our model approaches were implemented into a commercially available DEM code, PFC3D, that is commonly used by engineers. It is envisioned that once further developed, this new DEM modeling approach can be adapted to a wide range of engineering applications.

  20. KCl-induced high temperature corrosion of selected commercial alloys. Part II: alumina and silica-formers

    DEFF Research Database (Denmark)

    Kiamehr, Saeed; Dahl, Kristian Vinter; Montgomery, Melanie

    2016-01-01

    for 168 h in flowing N2(g)+5%O2(g)+15%H2O(g) (vol.%) with samples covered under KCl powder. A KCl-free exposure was also performed for comparison.Corrosion morphology and products were studied with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffractometry (XRD......Laboratory testing on selected alumina and silica-forming alloys was performed to evaluate their performance against high temperature corrosion induced by potassium chloride (KCl). The alloys studied were FeCrAlY, Kanthal APM, Nimonic 80A, 214, 153MA and HR160. Exposure was conducted at 600 °C......-chromium-silicon-oxygen containing layer forms as the innermost corrosion product. The layer was uniformly distributed over the surface and appears to render some protection as this alloy exhibited the best performance among the investigated alloys. To reveal further aspects of the corrosion mechanism, Nimonic 80A was exposed...

  1. Ni nanoparticles@Ni-Mo nitride nanorod arrays: a novel 3D-network hierarchical structure for high areal capacitance hybrid supercapacitors.

    Science.gov (United States)

    Ruan, Yunjun; Lv, Lin; Li, Zhishan; Wang, Chundong; Jiang, Jianjun

    2017-11-23

    Because of the advanced nature of their high power density, fast charge/discharge time, excellent cycling stability, and safety, supercapacitors have attracted intensive attention for large-scale applications. Nevertheless, one of the obstacles for their further development is their low energy density caused by sluggish redox reaction kinetics, low electroactive electrode materials, and/or high internal resistance. Here, we develop a facile and simple nitridation process to successfully synthesize hierarchical Ni nanoparticle decorated Ni 0.2 Mo 0.8 N nanorod arrays on a nickel foam (Ni-Mo-N NRA/NF) from its NiMoO 4 precursor, which delivers a high areal capacity of 2446 mC cm -2 at a current density of 2 mA cm -2 and shows outstanding cycling stability. The superior performance of the Ni-Mo-N NRA/NF can be ascribed to the metallic conductive nature of the Ni-Mo nitride, the fast surface redox reactions for the electrolyte ions and electrode materials, and the low contacted resistance between the active materials and the current collectors. Furthermore, a hybrid supercapacitor (HSC) is assembled using the Ni-Mo-N NRA/NF as the positive electrode and reduced graphene oxide (RGO) as the negative electrode. The optimized HSC exhibits excellent electrochemical performance with a high energy density of 40.9 W h kg -1 at a power density of 773 W kg -1 and a retention of 80.1% specific capacitance after 6000 cycles. These results indicate that the Ni-Mo-N NRA/NF have a promising potential for use in high-performance supercapacitors.

  2. Highway-rail intersection GPS-based in-vehicle warning systems - literature review and recommendations.

    Science.gov (United States)

    2012-12-31

    In 2008, there were 2,395 incidents at highway-rail intersections (level crossings) in the United States, resulting in 939 injuries and 287 fatalities. Crossing elimination, grade separation, and the implementation of traditional warning devices are ...

  3. Determination of an instability temperature for alloys in the cooling gas of a high temperature reactor

    International Nuclear Information System (INIS)

    Grimmer, H.; Grman, D.; Krompholz, K.; Zimmermann, U.; Ullrich, G.

    1985-05-01

    High temperature alloys designed to be used for components in the primary circuit of a helium cooled high temperature nuclear reactor show massive CO production above a certain temperature, called the instability temperature T/sub i/, which increases with increasing partial pressure of CO in the cooling gas. At p/sub CO/ = 15 microbar, T/sub i/ lies between 900 and 950 degrees C for the four alloys under investigation: T/sub i/ is lowest for the iron base alloy Incoloy 800 H and increases for the nickel base alloys in the order Inconel 617, HDA 230 and Nimonic 86. Measurements of T/sub i/ made at 3 different laboratories were compared and shown to agree for p/sub CO/ 25 microbar, compatible with CO production by a reaction of Cr2O3 with carbides. Some measurements of T/sub i/ on HDA 230 and Nimonic 86 were performed in the course of simulated reactor disturbances. They showed that the oxide layer looses its protective properties above T/sub i/. A highlight of the examinations was the detection of eta-carbides (M6C) with unusual properties. M6C is the only type of carbide occuring in HDA 230. An eta-carbide with a lattice constant of 1088.8 pm had developed at the surface of Nimonic 86 during pre-oxidation before the disturbance simulation. Its composition is estimated at Ni3SiMo2C. Eta-carbides containing Si and especially eta-carbides with lattice constants as low as 1088.8 pm have been described only rarely until now. (author)

  4. Relationship of heat treatment-mechanical properties of nickel base superalloys.; Relacion tratamiento termico-propiedades mecanicas de una superaleacion base niquel.

    Energy Technology Data Exchange (ETDEWEB)

    Zamora R, L

    1997-12-01

    The nickel-base superalloys have high strength, excellent corrosion resistant, and good creep and fatigue resistance. These alloy improved properties at high temperature derive their mechanical and creep behavior on {gamma} precipitate morphology, and the evolution of such morphology during different heat treatment conditions. The main microstructural variable of Nickel-based superalloys, responsible for the mechanical properties are: (a) amount and morphology of precipitates; (b) size and shape of grains; and (c) carbide distribution. In this work, a Nickel-base superalloy Nimonic 80A, modified little with Zr prepared by melting and casting practices of materials electrolytic in vacuum-induction melting (VIM) type Balzers, to obtain five alloys different and ingots of 2 Kg and 1 Kg, with composition in weight % of Nimonic 80-A is: Ni = bal (76.66), C = 0.01, Cr = 19.83, Fe = 2.4, Mn = 0.17, Si 0.47, Al = 0.19, Zr = 0.4. The solidification process is made in a steel mold. After having realized four thermal treatments, the most representative microstructures there were obtained. The results from tensile tests performed on Instron Servohydraulic testing systems at uniaxial dynamic testing, at constant speeds to ,0.2 cm/min, were: the yield strength, the ultimate strength value, percentage elongation and area reduction. Creep tests were performed at in stress of 90 and 129 MPa, at a temperature of 600 and 680 Centigrades at different times and width of specimen of 1 mm. The alloys were analyzed by MEB(JEOL 35CF) at different magnifications. The nucleation and growth of intergranular cavities during creep of alloy Nimonic M3, were investigated. One sample was deformed in creep at 129 MPa and 680 Centigrades during 110 hs. Creep samples were annealing heat treated at 800 Centigrades, during 7 days. After a careful sample preparation procedure, 3100 of cavities were measured in the sample . The cavity size distributions in the sample were obtained. (Abstract Truncated)

  5. Fracture of an industrial steam turbine horizontal joint nut upon tightening; Bruch der Mutter einer Horizontalteilfugenverschraubung einer Industriedampfturbine beim Anziehen

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Boromir; Giller, Madeleine; Neidel, Andreas; Riesenbeck, Susanne [Siemens AG - Gasturbinenwerk Berlin (Germany). Energy Sector Werkstoffprueflabor

    2017-11-01

    The nut of a horizontal joint fastener cracked upon tightening during assembly in an industrial steam turbine factory. It was previously used in an over-pressure test, but was otherwise not yet used in service. Nut and bolt were made of the nickel-based superalloy Nimonic 80A, a precipitation-hardenable wrought high-strength alloy with excellent creep and corrosion properties. Such alloys usually get a complex heat treatment after hot-rolling, comprising homogenizing and multiple ageing cycles. The subject nut failed due to an extreme case of mixed grain size which detrimentally affected mechanical properties and was attributed to an insufficient degree of deformation during hot rolling.

  6. Dimensional stability of some Fe-Ni-Cr alloys used in nuclear power generation

    International Nuclear Information System (INIS)

    Marucco, A.; Nath, B.

    1983-01-01

    The dimensional stability of four materials used in the nuclear power industry, viz Nimonic PE16, 20Cr-25Ni steel, Alloy 600 and Inconel 690, have been studied using X-ray diffractometry, electrical resistivity and thin foil microscopic techniques. Appreciable reductions in lattice parameters of these alloys occur on exposure to temperatures of 823 deg K and below. An order-disorder transformation has been found to be responsible for the observed behaviour. The transformation kinetics, associated microstructural changes and the implications for the usage of these materials are discussed. (author)

  7. Effect of helium on creep and fatigue (MAT 11)

    International Nuclear Information System (INIS)

    Schroeder, H.

    1991-03-01

    This final report contains experimental results on mechanical properties (creep, fatigue, tensile) and microstructural investigations (SEM, TEM) of pre-implanted samples of steels or alloys. (AISI 316, AISI 316L, DIN 1.4970, JPCA 8206, DIN 1.4914; Incoloy 800H, Hastelloy X, DIN 1.4981, (Fe 0.49 Ni 0.51 ) 3 V, Fe17Ni17Cr, Fe15Ni15Cr, Nimonic PE 16, Ni8Si). Furthermore theoretical aspects and developed models and mechanisms for helium embrittlement are described. This report is presented in the form of an extended summary without figures. (MM)

  8. Aleación superficial de superaleaciones base níquel mediante láser

    OpenAIRE

    Rodríguez, G. P.; García, I.; Damborenea, J. J.

    1998-01-01

    Ni based superalloys present a high oxidation resistance at high temperature as well as good mechanical properties. But new tecnhology developments forcé to research in this materials to improve their properties at high temperature. In this work, two Ni based superalloys (Nimonic 80A and Inconel 600) were surface alloyed with aluminium using a high power laser. SEM and EDX were used to study the microstructure of the obtained coatings. Alloyed specimens were tested at 1.273 K between 24 and 2...

  9. Surface alloying of nickel based superalloys by laser

    International Nuclear Information System (INIS)

    Rodriguez, G.P.; Garcia, I.; Damborenea, J.J. de

    1998-01-01

    Ni based superalloys present a high oxidation resistance at high temperature as well as good mechanical properties. But new technology developments force to research in this materials to improve their properties at high temperature. In this work, two Ni based superalloys (Nimonic 80A and Inconel 600) were surface alloyed with aluminium using a high power laser. SEM and EDX were used to study the microstructure of the obtained coatings. Alloyed specimens were tested at 1.273 K between 24 and 250 h. Results showed the generation of a protective and continuous coating of alumina on the laser treated specimens surface that can improve oxidation resistance. (Author) 8 refs

  10. On the cyclic stress-strain behavior and low cycle fatigue of aerospace materials

    Science.gov (United States)

    Burbach, J.

    1972-01-01

    The elastic-plastic deformation behavior under cyclic stress of a number of different engineering materials was experimentally investigated with the aid of high-precision methods of measuring, some of which had been newly developed. Experiments made with a variety of steels, the titanium alloy Ti-A16-V4, a cobalt (tungsten) alloy, the high-temperature material Nimonic 90 and Dural (A1-Cu) are reported. The theory given in an attempt to explain these experiments is aimed at finding general formulas for the cyclic stress-strain behavior materials.

  11. Bibliography on Hot Isostatic Pressing (HIP) Technology

    Science.gov (United States)

    1992-11-01

    Nimonic API, Rene’ 77 2. MA753, IN-853 7 3. C-103,WC-103 4. Alloy 454, PWA 1480 5. Mar- M250 , Maraging (250) 6. Rene 150, PA 101 (low C) 7. Inconel 718...Pressure Welding Parameters Bryant. W. A. Weld J 54 (12), 433-S-435-S, 1975 ( AD-DI02 316 Key Words: AISI 4340. MAR- M250 . AISI 1020, 9Ni-4Co steel. Inconel...creep rupture. hot corrosion, oxidation, grain size, thermomechanical treatment MAR- M250 1. Microstructures and Mechanical Properties of HIP

  12. Evaluation of the Low Heat Input Process for Weld Repair of Nickel-Base Superalloys

    Science.gov (United States)

    Durocher, J.; Richards, N. L.

    2011-10-01

    The repair of turbine blades and vanes commonly involves gas tungsten arc welding or an equivalent process, but unfortunately these components are often susceptible to heat-affected zone (HAZ) cracking during the weld repair process. This is a major problem especially in cast alloys due to their coarse-grain size and where the (Al + Ti) contents is in excess of 3-4%; vacuum brazing is also used but mainly on low stress non-rotating components such as vanes. Micro-welding has the potential to deposit small amounts of filler at low heat input levels with minimum HAZ and thus is an attractive process for depositing a quality weld. As with conventional fusion processes, the filler alloy is deposited by the generation of a low power arc between a consumable electrode and the substrate. The low heat input of this process offers unique advantages over more common welding processes such as gas tungsten arc, plasma arc, laser, and electron beam welding. In this study, the low heat input characteristic of micro-welding has been used to simulate weld repair using Inconel (IN) (Inconel and IN are trademarks of INCO Alloys International) 625, Rene (Rene is a trademark of General Electric Company) 41, Nimonic (Nimonic is a trademark of INCO Alloys International) 105 and Inconel 738LC filler alloys, to a cast Inconel 738LC substrate. The effect of micro-welding process parameters on the deposition rate, coating quality, and substrate has been investigated.

  13. Analysis of zirconium and nickel based alloys and zirconium oxides by relative and internal monostandard neutron activation analysis methods

    International Nuclear Information System (INIS)

    Shinde, Amol D.; Acharya, Raghunath; Reddy, Annareddy V. R.

    2017-01-01

    The chemical characterization of metallic alloys and oxides is conventionally carried out by wet chemical analytical methods and/or instrumental methods. Instrumental neutron activation analysis (INAA) is capable of analyzing samples nondestructively. As a part of a chemical quality control exercise, Zircaloys 2 and 4, nimonic alloy, and zirconium oxide samples were analyzed by two INAA methods. The samples of alloys and oxides were also analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and direct current Arc OES methods, respectively, for quality assurance purposes. The samples are important in various fields including nuclear technology. Samples were neutron irradiated using nuclear reactors, and the radioactive assay was carried out using high-resolution gamma-ray spectrometry. Major to trace mass fractions were determined using both relative and internal monostandard (IM) NAA methods as well as OES methods. In the case of alloys, compositional analyses as well as concentrations of some trace elements were determined, whereas in the case of zirconium oxides, six trace elements were determined. For method validation, British Chemical Standard (BCS)-certified reference material 310/1 (a nimonic alloy) was analyzed using both relative INAA and IM-NAA methods. The results showed that IM-NAA and relative INAA methods can be used for nondestructive chemical quality control of alloys and oxide samples

  14. Analysis of zirconium and nickel based alloys and zirconium oxides by relative and internal monostandard neutron activation analysis methods

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, Amol D.; Acharya, Raghunath; Reddy, Annareddy V. R. [Bhabha Atomic Research Centre, Mumbai (India)

    2017-04-15

    The chemical characterization of metallic alloys and oxides is conventionally carried out by wet chemical analytical methods and/or instrumental methods. Instrumental neutron activation analysis (INAA) is capable of analyzing samples nondestructively. As a part of a chemical quality control exercise, Zircaloys 2 and 4, nimonic alloy, and zirconium oxide samples were analyzed by two INAA methods. The samples of alloys and oxides were also analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and direct current Arc OES methods, respectively, for quality assurance purposes. The samples are important in various fields including nuclear technology. Samples were neutron irradiated using nuclear reactors, and the radioactive assay was carried out using high-resolution gamma-ray spectrometry. Major to trace mass fractions were determined using both relative and internal monostandard (IM) NAA methods as well as OES methods. In the case of alloys, compositional analyses as well as concentrations of some trace elements were determined, whereas in the case of zirconium oxides, six trace elements were determined. For method validation, British Chemical Standard (BCS)-certified reference material 310/1 (a nimonic alloy) was analyzed using both relative INAA and IM-NAA methods. The results showed that IM-NAA and relative INAA methods can be used for nondestructive chemical quality control of alloys and oxide samples.

  15. Microstructural and mechanical approaches of the selective laser melting process applied to a nickel-base superalloy

    International Nuclear Information System (INIS)

    Vilaro, T.; Colin, C.; Bartout, J.D.; Nazé, L.; Sennour, M.

    2012-01-01

    Highlights: ► We examine the as-fabricated microstructure of the Nimonic 263 processed by selective laser melting. ► We optimized heat treatments to modify the microstructure and improve the mechanical properties. ► We tested through tensile tests the various microstructures in order to compare the effects of the heat treatments. - Abstract: This article aims at presenting the Nimonic 263 as-processed microstructure of the selective laser melting which is an innovative process. Because the melting pool is small and the scanning speed of the laser beam is relatively high, the as-processed microstructure is out-of-equilibrium and very typical to additive manufacturing processes. To match the industrial requirement, the microstructures are modified through heat treatments in order to either produce precipitation hardening or relieve the thermal stresses. Tensile tests at room temperature give rise to high mechanical properties close or above those presented by Wang et al. . However, it is noted a strong anisotropy as a function of the building direction of the samples because of the columnar grain growth.

  16. Environmental aspects on LCF-life of Ni-base superalloys during long term operation; Miljoeinverkan paa LCF-egenskaper vid laanga drifttider hos superlegeringar

    Energy Technology Data Exchange (ETDEWEB)

    Moverare, Johan; Leijon, Gunnar; Palmert, Frans

    2012-02-15

    The applicability of fine grain polycrystalline nickel base superalloys in gas or steam turbine applications is often limited by their susceptibility to fast intergranular cracking during fatigue in combination with extended hold times at high temperatures and high tensile stresses. This effect is further enhanced in corrosive environments even at moderate temperatures such as 400-600 deg In this study the negative effect of SO{sub 2} + water vapour on the low cycle fatigue resistance of three different nickel based superalloys (Nimonic 901, Inconel 718 and 718 plus) has been studied at 450 deg and 550 deg. A negative effect was found on both the crack initiation and crack propagation process. The effect increases with increasing temperature and is likely to be influenced by both the chemical composition and the grain size of the material. The negative effect of water vapour + SO{sub 2} is manifested by a decreased resistance to cyclic plastic deformation and a transition from transcrystalline to intercrystalline fracture behaviour. In Nimonic 901 this negative effect increases with the degree of plastic deformation. For lower mechanical strain amplitudes where the number of cycles and the total exposure time is increased the environmental impact is reduced. Similar trends can also be noticed for the other alloys. The surface corrosion in air and in SO{sub 2} + water vapour are found to be rather similar in this study and it is therefore concluded that the surface scale can remain adherent and protective if the strains on the oxide scale are low. However, for LCF tests with higher strain ranges, the oxide scale will rupture preferably at the grain boundaries and intergranular microcracks will initiate which promotes inward diffusion of embritteling elements such as oxygen and sulphur. Inconel 718 seems to be more sensitive to SO{sub 2} + water vapour than Nimonic 901 when tested at 450. The overall resistance to LCF is however still higher in Inconel 718 for the

  17. Relationship of heat treatment-mechanical properties of nickel base superalloys

    International Nuclear Information System (INIS)

    Zamora R, L.

    1997-01-01

    The nickel-base superalloys have high strength, excellent corrosion resistant, and good creep and fatigue resistance. These alloy improved properties at high temperature derive their mechanical and creep behavior on γ precipitate morphology, and the evolution of such morphology during different heat treatment conditions. The main microstructural variable of Nickel-based superalloys, responsible for the mechanical properties are: a) amount and morphology of precipitates; b) size and shape of grains; and c) carbide distribution. In this work, a Nickel-base superalloy Nimonic 80A, modified little with Zr prepared by melting and casting practices of materials electrolytic in vacuum-induction melting (VIM) type Balzers, to obtain five alloys different and ingots of 2 Kg and 1 Kg, with composition in weight % of Nimonic 80-A is: Ni = bal (76.66), C = 0.01, Cr = 19.83, Fe = 2.4, Mn = 0.17, Si 0.47, Al = 0.19, Zr = 0.4. The solidification process is made in a steel mold. After having realized four thermal treatments, the most representative microstructures there were obtained. The results from tensile tests performed on Instron Servohydraulic testing systems at uniaxial dynamic testing, at constant speeds to ,0.2 cm/min, were: the yield strength, the ultimate strength value, percentage elongation and area reduction. Creep tests were performed at in stress of 90 and 129 MPa, at a temperature of 600 and 680 Centigrades at different times and width of specimen of 1 mm. The alloys were analyzed by MEB(JEOL 35CF) at different magnifications. The nucleation and growth of intergranular cavities during creep of alloy Nimonic M3, were investigated. One sample was deformed in creep at 129 MPa and 680 Centigrades during 110 hs. Creep samples were annealing heat treated at 800 Centigrades, during 7 days. After a careful sample preparation procedure, 3100 of cavities were measured in the sample . The cavity size distributions in the sample were obtained. The cavity growth rate, was

  18. The diffusional growth of a grain boundary crack

    International Nuclear Information System (INIS)

    Puls, M.P.; Dutton, R.

    1977-10-01

    This report considers the possibility of high temperature rupture occurring by a grain boundary diffusional mechanism. It is assumed that a pre-existing, intergranular crack grows by loss of atoms from the crack tip to the grain boundary. Rupture occurs when the crack has grown to a critical length. A theoretical treatment of the kinetics of crack growth is presented and equations are derived for the crack velocity and time to rupture. A comparison is made with a previous theoretical model developed by Charles, together with rupture data obtained experimentally for the nickel-based alloy, Nimonic 80A. We conclude that experimental verification of the theoretical models requires a comparison with crack velocity data rather than time to rupture data. (author)

  19. Pre-oxidation and its effect on reducing high-temperature corrosion of superheater tubes during biomass firing

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Kvisgaard, M.; Montgomery, Melanie

    2017-01-01

    Superheater tubes in biomass-fired power plants experience high corrosion rates due to condensation of corrosive alkali chloride-rich deposits. To explore the possibility of reducing the corrosion attack by the formation of an initial protective oxide layer, the corrosion resistance of pre......-oxidised Al and Ti-containing alloys (Kanthal APM and Nimonic 80A, respectively) was investigated under laboratory conditions mimicking biomass firing. The alloys were pre-oxidised at 900°C for 1 week. Afterwards, pre-oxidised samples, and virgin non-pre-oxidised samples as reference, were coated...... with a synthetic deposit of KCl and exposed at 560°C for 1 week to a gas mixture typical of biomass firing. Results show that pre-oxidation could hinder the corrosion attack; however, the relative success was different for the two alloys. While corrosion attack was observed on the pre-oxidised Kanthal APM, the pre...

  20. Design and placement considerations for propeller-type t-zero choppers

    International Nuclear Information System (INIS)

    Robinson, R.A.

    1998-01-01

    The author discusses factors to do with placement and running speeds of propeller-type t-zero choppers, as implemented at ISIS (on chopper spectrometers) and at LANSCE (on a reflectometer, chopper spectrometer and small-angle scattering instrument). In all cases, the purpose is to block the burst of high-energy neutrons that emanates from the source when the proton beam strikes the target, and still be fully open when the thermal neutrons of interest pass through the space occupied by the t-zero chopper. In general, roughly 30 cm of high-strength high-Ni alloy (like nimonic or inconel) is placed in the beam, and for background purposes, it is desirable to place the chopper as far upstream as possible

  1. Cobalt: A vital element in the aircraft engine industry

    Science.gov (United States)

    Stephens, J. R.

    1981-01-01

    Recent trends in the United States consumption of cobalt indicate that superalloys for aircraft engine manufacture require increasing amounts of this strategic element. Superalloys consume a lion's share of total U.S. cobalt usage which was about 16 million pounds in 1980. In excess of 90 percent of the cobalt used in this country was imported, principally from the African countries of Zaire and Zambia. Early studies on the roles of cobalt as an alloying element in high temperature alloys concentrated on the simple Ni-Cr and Nimonic alloy series. The role of cobalt in current complex nickel base superalloys is not well defined and indeed, the need for the high concentration of cobalt in widely used nickel base superalloys is not firmly established. The current cobalt situation is reviewed as it applies to superalloys and the opportunities for research to reduce the consumption of cobalt in the aircraft engine industry are described.

  2. Materials for advanced high temperature reactors

    International Nuclear Information System (INIS)

    Graham, L.W.

    1976-01-01

    The results recently obtained from the Dragon program are presented to illustrate materials behavior: (a) effect of temperature on oxidation and carburisation in HTR helium (variation in oxide depth and in C content of AISI 321 after 5000 hours in HTR helium; effect of temperature on surface scale formation in the γ' strengthened alloys Nimonic 80A and 713LC); (b) effect of alloy composition on oxidation and carburisation behavior (influence of Nb and Ti on the corrosion of austenitic steels; influence of Ti and Al in IN-102; weight gain of cast high Ni alloys); (c) effect of environment on creep strength (results of tests for hastelloy X, grade I inconel 625, grade II inconel 625 and inconel 617 in He and air between 750 and 800 0 C)

  3. Irradiation creep induced anisotropy in a/2 dislocation populations

    International Nuclear Information System (INIS)

    Gelles, D.S.

    1984-05-01

    The contribution of anisotropy in Burgers vector distribution to irradiation creep behavior has been largely ignored in irradiation creep models. However, findings on Frank loops suggest that it may be very important. Procedures are defined to identify the orientations of a/2 Burgers vectors for dislocations in face-centered cubic crystals. By means of these procedures the anisotropy in Burgers vector populations was determined for three Nimonic PE16 pressurized tube specimens irradiated under stress. Considerable anisotropy in Burgers vector population develops during irradiation creep. It is inferred that dislocation motion during irradiation creep is restricted primarily to a climb of a/2 dislocations on 100 planes. Effect of these results on irradiation creep modeling and deformation induced irradiation growth is considered

  4. Nuclear microprobe characterization of surface hardening by precipitation of chromium carbides after laser beam treatment of a Ni-Cr substrate

    International Nuclear Information System (INIS)

    Mosbah, M.; Gosset, J.; Trocellier, P.; Puig, T.; Cantarel, M.; Condat, M.

    1989-01-01

    Surface treatment by laser provides interesting solutions to the problem of accelerated wear of materials. The aim of the present study is the characterization of chromium carbides rich surface alloys after laser beam melting of a Ni 70 Cr 30 carbon precoated substrate. The carbon profiling of the lasered surface was performed by nuclear microprobe using the 12 C(d,p 0 ) 13 C reaction, Ni and Cr were evaluated by means of PIXE (Particle Induced X Ray Emission). The specificity of the method and the experimental conditions are explained. Wear results are very satisfactory and close to those obtained by injection of chromium carbide powders into the laser beam in the case of a Nimonic alloy: wear rates are divided by two orders of magnitude

  5. Solvent extraction of titanium(IV), zirconium(IV) and hafnium(IV) salicylates using liquid ion exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Sundaramurthi, N M; Shinde, V M

    1989-02-01

    A solvent extraction method is proposed for the extraction of quadrivalent titanium, zirconium an hafnium from salicylate media using liquid ion exchangers such as Aliquat 336 and trioctylamine dissolved in xylene. The optimum conditions were evaluated from a critical study of the following: pH, salicylate concentration, amine concentration, diluent and period of equilibration. The method allows the separation of titanium, zirconium and hafnium from binary mixtures containing commonly associated metal ions and is applicable to the analysis of real samples such as BCS-CRM 387 nimonic 901, BCS-CRM 243/4 ferro-titanium, BCS-CRM 307 magnesium alloy and BCS-CRM 388 zircon. Titanium is determined either with hydrogen peroxide or by atomic absorption spectrometry whereas zirconium and hafnium are determined spectrophotometrically with Alizarin Red S and Zylenol Orange, respectively. The results of both separation and analysis are reported. The method is precise, accurate and fast.

  6. Design of durability and lifetime assessment method under thermomechanical stress for thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hyun Gyoo; Choi, Young Kue; Jeon, Seol; Lee, Hee Soo [Pusan National University, Busan (Korea, Republic of); Jeon, Min Seok [Korea Testing Laboratory, Seoul (Korea, Republic of)

    2014-01-15

    A durability testing method under thermo-mechanical stress for thermal barrier coatings (TBC) specimens was designed by a combination of an electric furnace and a tensile testing machine, which was done on TBCs on NIMONIC 263 substrates by an atmospheric plasma spraying (APS) deposition method. The testing conditions were chosen according to a preliminary experiment that identified the elastic deformation region of the top coating and the substrate during mechanical loading. Surface cracking and a decrease in the thickness of the top coating, which are typical degradation behaviors under conventional thermal shock testing, were observed after the designed thermal fatigue test, and delamination at the top coating-bond coating interface occurred by the mechanical load. Lifetime assessment was conducted by statistical software using life cycle data which were obtained after the thermal fatigue test.

  7. The compatibility of candidate first wall metallic materials with impure helium

    International Nuclear Information System (INIS)

    Noda, T.; Okada, M.; Watanabe, R.

    1979-01-01

    The compatibilities of SUS 316 stainless steels, Nimonic PE 16, Nb-1% Zr, V-25% Mo, Mo, and TZM with the commercial grade helium (> 99.995%) and the helium containing oxygen of 13 vpm at temperatures from 873 to 1273 K were studied. SUS 316 and PE 16 were internally oxidized above 1100 K. The marked depletion of Cr and Mn in SUS 316 specimens was observed in the commercial grade helium above around 1100 K. Nb-1% Zr and V-25% Mo extremely absorbed oxygen and nitrogen from the helium gases and were deteriorated in the range of test temperatures. Mo and TZM appeared not to be affected by the exposure to the commercial grade helium at temperature up to 1273 K. However, Mo and TZM lost ductility at room temperature after exposure to helium above 1100 and 900 K respectively. (orig.)

  8. Creep rupture behavior of candidate materials for nuclear process heat applications

    International Nuclear Information System (INIS)

    Schubert, F.; te Heesen, E.; Bruch, U.; Cook, R.; Diehl, H.; Ennis, P.J.; Jakobeit, W.; Penkalla, H.J.; Ullrich, G.

    1984-01-01

    Creep and stress rupture properties are determined for the candidate materials to be used in hightemperature gas-cooled reactor (HTGR) components. The materials and test methods are briefly described based on experimental results of test durations of about20000 h. The medium creep strengths of the alloys Inconel-617, Hastelloy-X, Nimonic-86, Hastelloy-S, Manaurite-36X, IN-519, and Incoloy-800H are compared showing that Inconel-617 has the best creep rupture properties in the temperature range above 800 0 C. The rupture time of welded joints is in the lower range of the scatterband of the parent metal. The properties determined in different simulated HTGR atmospheres are within the scatterband of the properties obtained in air. Extrapolation methods are discussed and a modified minimum commitment method is favored

  9. Observations of cellular transformation products in nickel-base superalloys

    International Nuclear Information System (INIS)

    Barlow, C.Y.; Ralph, B.

    1979-01-01

    Transmission electron microscopy has been used to identify the products in cellularly transformed regions of alloys based on the Nimonic 80 A composition. The commercial alloy is shown to undergo a small degree of cellular transformation even after conventional heat treatments, while recrystallization is found to increase the incidence of this reaction type. Low carbon versions of this alloy demonstrate cellular precipitation over a wider range of heat treatments. It is shown that the cellular reaction may take place in these alloys under a variety of different conditions and with a range of driving forces. Reasons for this unexpected behaviour are offeredm as is a suggestion as to why the cellular reaction occurs on a local scale. (author)

  10. Aleación superficial de superaleaciones base níquel mediante láser

    Directory of Open Access Journals (Sweden)

    Rodríguez, G. P.

    1998-04-01

    Full Text Available Ni based superalloys present a high oxidation resistance at high temperature as well as good mechanical properties. But new tecnhology developments forcé to research in this materials to improve their properties at high temperature. In this work, two Ni based superalloys (Nimonic 80A and Inconel 600 were surface alloyed with aluminium using a high power laser. SEM and EDX were used to study the microstructure of the obtained coatings. Alloyed specimens were tested at 1.273 K between 24 and 250 h. Results showed the generation of a protective and continuous coating of alumina on the laser treated specimens surface that can improve oxidation resistance.

    Las superaleaciones base níquel presentan una elevada resistencia a la oxidación a alta temperatura, así como excelentes propiedades mecánicas. Los nuevos desarrollos tecnológicos (condiciones cada vez más agresivas obligan a una casi continua modificación de dichas aleaciones. En el presente trabajo, dos superaleaciones base níquel (Nimonic 80A e Inconel 600 se alean superficialmente con aluminio utilizando un láser de alta potencia. Se estudia la microestructura de la capas obtenidas mediante SEM y EDX. Se realizan ensayos de oxidación a 1.273 K sobre las probetas aleadas y sobre el material base durante tiempos variables entre 24 y 250 h. Los resultados indican la formación de una capa protectora de alúmina sobre las probetas aleadas que puede incrementar la resistencia a la oxidación.

  11. Investigations on the determination of corrosion kinetics and the structure of corrosion products on high-temperature alloys under low oxygen partial pressures

    International Nuclear Information System (INIS)

    Poestges, A.; Naoumidis, A.; Nickel, H.

    1979-04-01

    On three nickel-base-alloys (NIMONIC 80A, INCONNEL 617 and ALLOY 713LC), which are planned as materials for components of the primary cooling circuit of high-temperature reactors, studies for the determination of the oxidation behaviour under reactor relevant conditions were performed. The test conditions were fixed at an oxygen partial pressure of 10 -16 bars with a total pressure of 0,2 bars and a temperature of 1080 0 C. The use of the X-ray diffraction analysis on the oxidised samples of type NIMONIC 80A showed the corrosion products Cr 2 O 3 , TiO 2 and Cr 2 Ti 2 O 7 in the outer oxide coating as well as Al 2 O 3 in the inner oxide zone. The samples of the alloy type INCOEL 617 showed the oxides Cr 2 O 3 and Cr 2 Ti 2 O 7 in the outer oxide coating. Samples of the alloy ALLOY 713LC showed Cr 2 O 3 and CrNbO 4 in the outer oxide coating and Al 2 O 3 in the zone of inner oxidation. Sufficient detection certainty was only ascertained by investigating samples with plane surface. For both alloys first mentioned, it was possible to prove the validity of the paralinear relationship W = k x t -1 / 2 - a x t for the increase in weight for the explanation of the time law of the oxidation. For the non-destructive determination of the oxide coating thickness on the alloys samples, the X-ray fluorescence analysis gave reproducible results of good precision. (orig.) [de

  12. Increase in the thermal strength of the binder phase of Cermets; Steigerung der Warmfestigkeit der Bindephase von Cermets

    Energy Technology Data Exchange (ETDEWEB)

    Grewe, H. [Krupp-Entwicklungszentrum, Bereich Werkstofftechnik, Essen (Germany); Kolaska, H. [Entwicklung Hartstoffe, Krupp Widia GmbH, Essen (Germany)

    1995-05-01

    According to recent investigations, hard metals with a good profile of characteristics can be produced from tungsten carbide with appropriate sintering conditions and with optimized alloying ratios in the Fe-Co-Ni system. The Co binder phase is substituted by a Fe-Co-Ni binder phase, by Co-Ni or Fe-Ni, or by alloys of the Nimonic type. The following analyses were carried out for the sintered HIP state, the quenched state, and the state of maximum magnetic and mechanical hardening: Light microscopy, measurement of the mechanical and technical characteristics, analysis of oxidation characteristics, hot hardness and edge-holding property, investigation of precipitation and hardening processes in the binder phase by a metallurgical analysis, and attempts to describe the kinetics of hardening. (orig./MM) [Deutsch] Neuere Untersuchungsergebnisse ergeben Hinweise, wonach unter Einhaltung bestimmter Sinterbedingungen und nach Optimierung der Legierungsverhaeltnisse im Dreistoffsystem Eisen-Cobalt-Nickel gute Aussichten fuer die Herstellung von Hartmetallen auf Wolframcarbid-Basis mit einem guenstigen Eigenschaftsprofil bestehen. Die uebliche Cobalt-Bindephase wird dabei durch eine Fe-Co-Ni-Bindephase, durch Co-Ni oder Fe-Ni oder durch Legierungen vom Nimonic-Typ substituiert. Aufbauend auf diesen Kenntnissen wurde eine konzeptionelle Modifizierung der Bindephase von Cermets vorgenommen, die auf einer Co-Ni-Legierung basiert und durch die Ausscheidung von intermetallischen Phasen mit moeglichst einfacher Struktur aushaertet. Dabei eilt die magnetische Aushaertung der mechanischen Aushaertung des Cermet-Versuchswerkstoffs voraus. Fuer den Sinter-HIP-Zustand, fuer den Abschreckzustand sowie fuer den Zustand der maximalen magnetischen und der maximalen mechanischen Aushaertung wurden folgende Untersuchungen durchgefuehrt: Lichtmikroskopie Messung der mechanisch-technologischen Eigenschaften, Beurteilung von Oxidationsverhalten, Warmhaerte und Schneidhaltigkeit, Untersuchung

  13. Selection of a high performance alloy for gas turbine blade using finite element methods

    International Nuclear Information System (INIS)

    Khawaja, H.A.; Khan, A.M.; Ali, S.T.

    2007-01-01

    With the extensive increase in the utilization of energy resources in the modern era, the need of energy extraction from various resources has pronounced in recent years. Thus comprehensive efforts have been made around the globe in the technological development of turbo machines where means of energy extraction is energized fluids. This development led the eviation industry to power boost due to better performing engines. Meanwhile, the structural conformability requirements relative to the functional requirements have also increased with the advent of newer, better performing materials. Thus there is a need to study the material behavior and its usage with the idea of selecting the best possible material for its application. In this work a gas turbine blade of a small turbofan engine, where geometry and aerodynamic data was available, was analyzed for its structural behavior in the proposed mission envelope, where the engine turbine is subjected to high thermal, inertial and aerodynamic loads. FE linear stress analysis was carried out on the turbine blade. The results revealed the upper limit of UTS for the blade. Based on the limiting factor, high performance alloys were selected from the literature. The two most recommended alloy categories for gas turbine blades are NIMONIC and INCONEL from where total of 21 types of INCONEL alloys and 12 of NIMONIC alloys, available on on commercial bases, were analyzed individually to meet the INCONEL alloys for further analysis. On the basis of stress-strain behavior of finalized alloys, the FE restriction of UFOS of 1.33 and yield strength. Final selection is made keeping in view other factors like manufacturability and workability in due consideration. (author)

  14. Development of service-relevant materials data and economic quality assurance and machining procedures for gas turbine blades. Final report; Entwicklung betriebsrelevanter Werkstoffkennwerte und wirtschaftlicher Qualitaetssicherungs- und Bearbeitungsverfahren fuer GT-Schaufeln. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Buergel, R.; Rechtenbacher, H.

    1994-01-01

    In the frame of the reported project, together with the programme partners, optimization of service relevant properties as well as modification of manufacturing procedures for the forged alloy Nimonic 101 were achieved. These results are directly implementable into serial production and cause improved service reliability and economic benefit. For the forged alloy Udimet 720 materials data were generated in accordance with the programme plan. The final evaluation for this alloy will be performed by the project partner Siemens-KWU. The qualification of fine-grained investment cast blades of IN 792 for large rear=stage blading is not yet fully completed. Three major questions are lacking final answers: - Does a stress rupture strength advantage exist over the forged alloy Udimet 720/coarse/grained? - Can a high cycle fatigue strength as high as that for Udimet 720/coarse-grained be met reproducibly? - Does the investment cast blades offer a cost advantage over the forged ones - technical qualification assumed? The programme helped significantly in preparing the right answers to these questions. (orig.) [Deutsch] Im Rahmen des berichteten Teilvorhabens ist es in Zusammenarbeit mit den Projektpartnern gelungen, fuer die Schmiedelegierung Nimonic 101 die betriebsrelevanten Eigenschaften zu optimieren, sowie die Schaufelherstellung so zu modifizieren, dass die Betriebszuverlaessigkeit verbessert wird. Diese Ergebnisse sind direkt in die Serienfertigung implementierbar und damit wirtschaftlich nutzbar. Fuer die Schmiedelegierung Udimet 720 wurden im Rahmen des Projektverbundes Werkstoffkennwerte ermittelt. Die Gesamtauswertung fuer diesen Werkstoff erfolgt von Projektpartner Siemens-KWU. Das Bild zur Qualifikation feinkoerniger Feingussschaufeln ist noch nicht restlos klar. Drei wesentliche, noch abschliessend zu beantwortende Fragen sind: - Ergibt sich ein Zeitstandfestigkeitsvorteil gegenueber der Schmiedelegierung Udimet 720/Grobkorn? - Laesst sich reproduzierbar eine

  15. Performance of candidate gas turbine abradeable seal materials in high temperature combustion atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Simms, N.J. [Cranfield University, Power Generation Technology Centre, Cranfield, Beds, MK43 0AL (United Kingdom); Norton, J.F. [Cranfield University, Power Generation Technology Centre, Cranfield, Beds, MK43 0AL (United Kingdom); Consultant in Corrosion Science and Technology, Hemel Hempstead, Herts HP1 1SR (United Kingdom); McColvin, G. [Siemens Industrial Turbines Ltd., Lincoln, LN5 7FD (United Kingdom)

    2005-11-01

    The development of abradeable gas turbine seals for higher temperature duties has been the target of an EU-funded R and D project, ADSEALS, with the aim of moving towards seals that can withstand surface temperatures as high as {proportional_to} 1100 C for periods of at least 24,000 h. The ADSEALS project has investigated the manufacturing and performance of a number of alternative materials for the traditional honeycomb seal design and novel alternative designs. This paper reports results from two series of exposure tests carried out to evaluate the oxidation performance of the seal structures in combustion gases and under thermal cycling conditions. These investigations formed one part of the evaluation of seal materials that has been carried out within the ADSEALS project. The first series of three tests, carried out for screening purposes, exposed candidate abradeable seal materials to a simulated natural gas combustion environment at temperatures within the range 1050-1150 C in controlled atmosphere furnaces for periods of up to {proportional_to} 2,500 h with fifteen thermal cycles. The samples were thermally cycled to room temperature on a weekly basis to enable the progress of the degradation to be monitored by mass change and visual observation, as well as allowing samples to be exchanged at planned intervals. The honeycombs were manufactured from PM2000 and Haynes 214. The backing plates for the seal constructions were manufactured from Haynes 214. Some seals contained fillers or had been surface treated (e.g. aluminised). The second series of three tests were carried out in a natural gas fired ribbon furnace facility that allowed up to sixty samples of candidate seal structures (including honeycombs, hollow sphere structures and porous ceramics manufactured from an extended range of materials including Aluchrom YHf, PM2Hf, Haynes 230, IN738LC and MarM247) to be exposed simultaneously to a stream of hot combustion gas. In this case the samples were cooled

  16. Materials for advanced ultrasupercritical steam turbines

    Energy Technology Data Exchange (ETDEWEB)

    Purgert, Robert [Energy Industries Of Ohio Inc., Independence, OH (United States); Shingledecker, John [Energy Industries Of Ohio Inc., Independence, OH (United States); Saha, Deepak [Energy Industries Of Ohio Inc., Independence, OH (United States); Thangirala, Mani [Energy Industries Of Ohio Inc., Independence, OH (United States); Booras, George [Energy Industries Of Ohio Inc., Independence, OH (United States); Powers, John [Energy Industries Of Ohio Inc., Independence, OH (United States); Riley, Colin [Energy Industries Of Ohio Inc., Independence, OH (United States); Hendrix, Howard [Energy Industries Of Ohio Inc., Independence, OH (United States)

    2015-12-01

    The U.S. Department of Energy (DOE) and the Ohio Coal Development Office (OCDO) have sponsored a project aimed at identifying, evaluating, and qualifying the materials needed for the construction of the critical components of coal-fired power plants capable of operating at much higher efficiencies than the current generation of supercritical plants. This increased efficiency is expected to be achieved principally through the use of advanced ultrasupercritical (A-USC) steam conditions. A limiting factor in this can be the materials of construction for boilers and for steam turbines. The overall project goal is to assess/develop materials technology that will enable achieving turbine throttle steam conditions of 760°C (1400°F)/35MPa (5000 psi). This final technical report covers the research completed by the General Electric Company (GE) and Electric Power Research Institute (EPRI), with support from Oak Ridge National Laboratory (ORNL) and the National Energy Technology Laboratory (NETL) – Albany Research Center, to develop the A-USC steam turbine materials technology to meet the overall project goals. Specifically, this report summarizes the industrial scale-up and materials property database development for non-welded rotors (disc forgings), buckets (blades), bolting, castings (needed for casing and valve bodies), casting weld repair, and casting to pipe welding. Additionally, the report provides an engineering and economic assessment of an A-USC power plant without and with partial carbon capture and storage. This research project successfully demonstrated the materials technology at a sufficient scale and with corresponding materials property data to enable the design of an A-USC steam turbine. The key accomplishments included the development of a triple-melt and forged Haynes 282 disc for bolted rotor construction, long-term property development for Nimonic 105 for blading and bolting, successful scale-up of Haynes 282 and Nimonic 263 castings using

  17. Crack initiation and crack growth in high temperature materials under cyclic thermal stresses; Rissinitiierung und Risswachstum in Hochtemperaturwerkstoffen unter zyklisch thermischer Beanspruchung

    Energy Technology Data Exchange (ETDEWEB)

    Gruen, C.

    1996-12-01

    The high temperatures of use in drive units, such as the combustion chamber or the hot gas turbine, for example, usually cause high temperature changes. Great temperature differences occur for short periods in the components, and thermal shock is produced. In this work, theoretical and experimental investigations are introduced on crack initiation and crack growth in high temperature materials under cyclic thermal stresses. The experiments were carried out with the inter-metallic phase Ni{sub 3}Al, the nickel-based alloy Nimonic 80A and the iron-based alloy PM 2000 strengthened by oxide dispersion (ODS). A characteristic crack appearance picture was found for each material, which was examined more closely. The stresses occurring in the sample during one cycle were calculated with the aid of the finite element program ABAQUS, knowing the specific material parameters. Based on the linear-elastic fracture mechanics, stress intensity factors were calculated on the superimposition principle. Using the material data from isothermal crack propagation experiments, the prediction of fatigue crack spread with cyclic thermal stresses is compared with the experimental findings. (orig./AKF) [Deutsch] Die hohen Einsatztemperaturen in Antriebsaggregaten wie z.B. der Brennkammer oder der Heissgasturbine bedingen in der Regel hohe Temperaturwechsel. Dabei treten kurzzeitig grosse Temperaturunterschiede in den Bauteilen auf, ein Thermoschock wird erzeugt. In der vorliegenden Arbeit werden theoretische und experimentelle Untersuchungen zur Rissinitiierung und zum Risswachstum in Hochtemperaturwerkstoffen unter zyklisch thermischer Belastung vorgestellt. Die Experimente wurden mit der intermetallischen Phase Ni{sub 3}Al, der Nickelbasislegierung Nimonic 80A und der oxid-dispersionsverfestigten (ODS) Eisenbasislegierung PM2000 durchgefuehrt. Fuer jeden Werkstoff stellte sich ein charakteristisches Risserscheinungsbild dar, das naeher untersucht wurde. Die in der Probe auftretenden

  18. Long-term behaviour of heat-resistant steels and high-temperature materials

    International Nuclear Information System (INIS)

    1987-01-01

    This book contains 10 lectures with the following subjects: On the effect of thermal pretreatment on the structure and creep behaviour of the alloy 800 H (V. Guttmann, J. Timm); Material properties of heat resistant ferritic and austenitic steels after cold forming (W. Bendick, H. Weber); Investigations for judging the working behaviour of components made of alloy 800 and alloy 617 under creep stress (H.J. Penkalla, F. Schubert); Creep behaviour of gas turbine materials in hot gas (K.H. Kloos et al.); Effect of small cold forming on the creep beahviour of gas turbine blades made of Nimonic 90 (K.H. Keienburg et al.); Investigations on creep fatigue alternating load strength of nickel alloys (G. Raule); Change of structure, creep fatigue behaviour and life of X20 Cr Mo V 12 1 (by G. Eggeler et al.); Investigations on thermal fatigue behaviour (K.H. Mayer et al.); Creep behaviour of similar welds of the steels 13 Cr Mo 4 4, 14 MoV 6 3, 10 Cr Mo 910 and GS-17 Cr Mo V 5 11 (K. Niel et al.); Determining the creep crack behaviour of heat resistant steels with samples of different geometry (K. Maile, R. Tscheuschner). (orig.,/MM) [de

  19. Materials Performance in USC Steam

    Energy Technology Data Exchange (ETDEWEB)

    G. R. Holcomb, P. Wang, P. D. Jablonski, and J. A. Hawk

    2010-05-01

    The proposed steam inlet temperature in the Advanced Ultra Supercritical (A-USC) steam turbine is high enough (760 °C) that traditional turbine casing and valve body materials such as ferritic/martensitic steels will not suffice due to temperature limitations of this class of materials. Cast versions of several traditionally wrought Ni-based superalloys were evaluated for use as casing or valve components for the next generation of industrial steam turbines. The full size castings are substantial: 2-5,000 kg each half and on the order of 100 cm thick. Experimental castings were quite a bit smaller, but section size was retained and cooling rate controlled to produce equivalent microstructures. A multi-step homogenization heat treatment was developed to better deploy the alloy constituents. The most successful of these cast alloys in terms of creep strength (Haynes 263, Haynes 282, and Nimonic 105) were subsequently evaluated by characterizing their microstructure as well as their steam oxidation resistance (at 760 and 800 °C).

  20. Cast Alloys for Advanced Ultra Supercritical Steam Turbines

    Energy Technology Data Exchange (ETDEWEB)

    G. R. Holcomb, P. Wang, P. D. Jablonski, and J. A. Hawk,

    2010-05-01

    The proposed steam inlet temperature in the Advanced Ultra Supercritical (A-USC) steam turbine is high enough (760 °C) that traditional turbine casing and valve body materials such as ferritic/martensitic steels will not suffice due to temperature limitations of this class of materials. Cast versions of several traditionally wrought Ni-based superalloys were evaluated for use as casing or valve components for the next generation of industrial steam turbines. The full size castings are substantial: 2-5,000 kg each half and on the order of 100 cm thick. Experimental castings were quite a bit smaller, but section size was retained and cooling rate controlled to produce equivalent microstructures. A multi-step homogenization heat treatment was developed to better deploy the alloy constituents. The most successful of these cast alloys in terms of creep strength (Haynes 263, Haynes 282, and Nimonic 105) were subsequently evaluated by characterizing their microstructure as well as their steam oxidation resistance (at 760 and 800 °C).

  1. Static Structural and Modal Analysis of Gas Turbine Blade

    Science.gov (United States)

    Ranjan Kumar, Ravi; Pandey, K. M., Prof.

    2017-08-01

    Gas turbine is one of the most versatile items of turbo machinery nowadays. It is used in different modes such as power generation, oil and gas, process plants, aviation, domestic and related small industries. This paper is based on the problems concerning blade profile selection, material selection and turbine rotor blade vibration that seriously impact the induced stress-deformation and structural functioning of developmental gas turbine engine. In this paper for generating specific power by rotating blade at specific RPM, blade profile and material has been decided by static structural analysis. Gas turbine rotating blade RPM is decided by Modal Analysis so that the natural frequency of blade should not match with the excitation frequency. For the above blade profile has been modeled in SOLIDWORKS and analysis has been done in ANSYS WORKBENCH 14. Existing NACA6409 profile has been selected as base model and then it is modified by bending it through 72.5° and 145°. Hence these three different blade profiles have been analyzed for three different materials viz. Super Alloy X, Nimonic 80A and Inconel 625 at three different speed viz. 20000, 40000 and 60000RPM. It is found that NACA6409 with 72.5° bent gives best result for all material at all speed. Among all the material Inconel 625 gives best result. Hence Blade of Inconel 625 having 72.5° bent profile is the best combination for all RPM.

  2. Radiation damage simulation studies of selected austenitic and ferritic/martensitic alloys for fusion reactor structural applications

    International Nuclear Information System (INIS)

    Mazey, D.J.; Walters, G.P.; Buckley, S.N.; Bullough, R.; Hanks, W.; Bolster, D.E.J.; Sowden, B.C.; Lurcook, D.; Murphy, S.M.

    1985-03-01

    Results are given of an investigation of the radiation damage stability of selected austenitic and ferritic alloys following ion bombardment in the Harwell VEC to simulate fusion-reactor exposures up to 110 dpa at temperatures from 425 deg to 625 deg C. Gas production rates appropriate to CTR conditions were simulated using a mixed beam of (4 MeV He + 2 MeV H 2 ) in the ratio 1:4 He:H. A beam of 46 MeV Ni or 20 MeV Cr ions was used in sequence with the mixed gas beam to provide a gas/damage ratio of 13 appm He/dpa at a damage rate of approx. 1 dpa/hr. The materials were investigated using TEM and comprised three austenitic alloys: European reference 316L, 316-Ti, 316-Nb; four high-nickel alloys: Fe/25 Ni/8Cr, Inconel 625, Inconel 706 and Nimonic PE16, and four ferritic/martensitic alloys: FV 448, FV 607, CRM 12 and FI. Some data were obtained for a non-magnetic structural alloy Nonmagne-30. The swelling behaviour is reported. The overall results of the study indicate that on a comparative basis the ferritic alloys are the most swelling-resistant, whilst the high-nickel alloys have an acceptable low swelling response up to 110 dpa. The 316 alloys tested have shown an unfavourable swelling response. (author)

  3. Effects of Stress Ratio and Microstructure on Fatigue Failure Behavior of Polycrystalline Nickel Superalloy

    Science.gov (United States)

    Zhang, H.; Guan, Z. W.; Wang, Q. Y.; Liu, Y. J.; Li, J. K.

    2018-05-01

    The effects of microstructure and stress ratio on high cycle fatigue of nickel superalloy Nimonic 80A were investigated. The stress ratios of 0.1, 0.5 and 0.8 were chosen to perform fatigue tests in a frequency of 110 Hz. Cleavage failure was observed, and three competing failure crack initiation modes were discovered by a scanning electron microscope, which were classified as surface without facets, surface with facets and subsurface with facets. With increasing the stress ratio from 0.1 to 0.8, the occurrence probability of surface and subsurface with facets also increased and reached the maximum value at R = 0.5, meanwhile the probability of surface initiation without facets decreased. The effect of microstructure on the fatigue fracture behavior at different stress ratios was also observed and discussed. Based on the Goodman diagram, it was concluded that the fatigue strength of 50% probability of failure at R = 0.1, 0.5 and 0.8 is lower than the modified Goodman line.

  4. Alloy development for cladding and duct applications

    International Nuclear Information System (INIS)

    Straalsund, J.L.; Johnson, G.D.

    1981-01-01

    Three general classes of materials under development for cladding and ducts are listed. Solid solution strengthened, or austenitic, alloys are Type 316 stainless steel and D9. Precipitation hardened (also austenitic) alloys consist of D21, D66 and D68. These alloys are similar to such commercial alloys as M-813, Inconel 706, Inconel 718 and Nimonic PE-16. The third general class of alloys is composed of ferritic alloys, with current emphasis being placed on HT-9, a tempered martensitic alloy, and D67, a delta-ferritic steel. The program is comprised of three parallel paths. The current reference, or first generation alloy, is 20% cold worked Type 316 stainless steel. Second generation alloys for near-term applications include D9 and HT-9. Third generation materials consist of the precipitation strengthened steels and ferritic alloys, and are being considered for implementation at a later time than the first and second generation alloys. The development of second and third generation materials was initiated in 1974 with the selection of 35 alloys. This program has proceeded to today where there are six advanced alloys being evaluated. These alloys are the developmental alloys D9, D21, D57, D66 and D68, together with the commerical alloy, HT-9. The status of development of these alloys is summarized

  5. Deposition and characterization of plasma sprayed Ni-5A1/ magnesia stabilized zirconia based functionally graded thermal barrier coating

    International Nuclear Information System (INIS)

    Baig, M N; Khalid, F A

    2014-01-01

    Thermal barrier coatings (TBCs) are employed to protect hot section components in industrial and aerospace gas turbine engines. Conventional TBCs frequently fail due to high residual stresses and difference between coefficient of thermal expansion (CTE) of the substrate and coatings. Functionally graded thermal barrier coatings (FG-TBCs) with gradual variation in composition have been proposed to minimize the problem. In this work, a five layered functionally graded thermal barrier coating system was deposited by atmospheric plasma spray (APS) technique on Nimonic 90 substrates using Ni-5Al as bond coat (BC) and magnesia stabilized zirconia as top coat (TC). The coatings were characterized by SEM, EDS, XRD and optical profilometer. Microhardness and coefficient of thermal expansion of the five layers deposited as individual coatings were also measured. The deposited coating system was oxidized at 800°C. SEM analysis showed that five layers were successfully deposited by APS to produce a FG-TBC. The results also showed that roughness (Ra) of the individual layers decreased with an increase in TC content in the coatings. It was found that microhardness and CTE values gradually changed from bond coat to cermet layers to top coat. The oxidized coated sample revealed parabolic behavior and changes in the surface morphology and composition of coating

  6. Dispersion-Type Absorbing Materials for the Control Organs of Thermal Reactors; Absorbants du Type a Dispersion pour les Organes de Commande des Reacteurs a Neutrons Thermiques; Pogloshchayushchie materialy dispersionnogo tipa dlya organov regulirovaniya teplovykh reaktorov; Absorbentes de Tipo Dispersion para los Organos de Mando de los Reactores Termicos

    Energy Technology Data Exchange (ETDEWEB)

    Nosov, V. I.; Ponomarjov-Stepnoj, H. H.; Portnoj, K. I.; Savel' ev, E. G.

    1964-06-15

    The paper gives the results of a study of the physical characteristics of NIMONIC-type absorbing alloys with oxides of rare-earth elements dispersed in them (gadolinium, samarium, europium etc. ). The paper discusses changes in absorbing capacity in relation to the composition of the material, describes the mechanical and thermophysical properties of the absorbing materials as a function of the concentration of absorber introduced into the alloy and, finally, gives the results of a study of the effect of radiation on the properties of the materials. It is shown that absorbing alloys with oxides of rare-earth elements dispersed in the metallic matrix possess considerable absorbing capacity for relatively small amounts of absorber in the alloy (5 to 10%). When oxides of rare-earth elements are added, NIMONIC-type alloys have relatively high resistance and thermophysical characteristics (o{sub B}, E, {lambda}) at high temperatures for absorber concentrations up to about 10%. Dispersion materials of this type have satisfactory radiation stability in a radiation field of about 3 x 10{sup 20}n/cm{sup 2} at high temperature. (author) [French] Les auteurs exposent les resultats de recherches sur les caracteristiques physiques des alliages absorbants du type nimonik, contenant des terres rares dispersees dans leur masse (gadolinium, samarium, europium, etc.). Ils examinent les variations de la capacite d'absorption selon la composition du materiau; on donne des indications sur les caracteristiques mecaniques et thermophysiques des absorbants en fonction de la concentration de Tabsorbeur incorpore dans l 'alliage ainsi que les resultats d 'une etude relative a l 'influence de l'irradiation sur ces caracteristiques. Ils montrent que les alliages absorbants contenant des oxydes de terres rares disperses dans une matrice metallique ont une capacite d'absorption importante pour une teneur de l'alliage relativement faible en'matieres absorbantes (environ 5 a 10%). Les alliages du

  7. Social facilitation in virtual reality-enhanced exercise: competitiveness moderates exercise effort of older adults

    Directory of Open Access Journals (Sweden)

    Anderson-Hanley C

    2011-10-01

    Full Text Available Cay Anderson-Hanley1,2, Amanda L Snyder1, Joseph P Nimon1, Paul J Arciero1,21Healthy Aging and Neuropsychology Lab, Department of Psychology, Union College, Schenectady, NY, USA; 2Health and Exercise Sciences Department, Skidmore College, Saratoga Springs, NY, USAAbstract: This study examined the effect of virtual social facilitation and competitiveness on exercise effort in exergaming older adults. Fourteen exergaming older adults participated. Competitiveness was assessed prior to the start of exercise. Participants were trained to ride a “cybercycle;” a virtual reality-enhanced stationary bike with interactive competition. After establishing a cybercycling baseline, competitive avatars were introduced. Pedaling effort (watts was assessed. Repeated measures ANOVA revealed a significant group (high vs low competitiveness X time (pre- to post-avatar interaction (F[1,12] = 13.1, P = 0.003. Virtual social facilitation increased exercise effort among more competitive exercisers. Exercise programs that match competitiveness may maximize exercise effort.Keywords: exercise, aging, virtual reality, competitiveness, social facilitation, exercise intensity

  8. Damage of metal surfaces by a hot, dense deuterium plasma

    International Nuclear Information System (INIS)

    Panayotou, N.F.

    1978-01-01

    The effect of differences in alloy chemistry and systematic changes in microstructural interface density on the occurrence of unipolar arcing was studied. The effect of thermionic emission is examined by comparing the refractory metals W, Nb, and Nb-751 alloy to the non-refractory stainless steels, AISI 304, 316 and Nimonic PE-16. The effect of alloying additions is examined by comparing Mo containing 316 and Mo free 304 stainless steels as well as Zr containing Nb-751 and Zr free Nb. The effect of interface density is examined by systematically varying the density of microstructural interfaces in AISI 4130, a ferritic steel. Although most of the metals and alloys studied are candidate fusion reactor materials, 4130 was chosen on the basis of our ability to modify the density of microstructural interfaces in the material by heat treatment. The results are discussed with respect to available unipolar arcing theory. The significance of the work, in terms of actual power reactors is assessed and the need for further work defined

  9. Boride particles in a powder metallurgy superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Witt, M C; Charles, J A

    1985-12-01

    Using optical and electron metallography, the composition, morphology, and distribution of M/sub 3/B/sub 2/ borides in as-hipped (hot isostatically pressed) samples of the powder metallurgy superalloy Nimonic AP1 have been determined. Two types of boride are present depending on the HIP temperature. Hipping below the boride solvus results in low-aspect ratio particles, distributed both inter- and intragranularly. Hipping above the boride solvus produces high-aspect ratio particles which are exclusively intergranular. A small difference in both lattice parameter and composition has been measured. Electron energy loss spectroscopy of the particles has confirmed the presence of boron, and laser ion-induced mass analysis has indicated a low carbon level. The higher susceptibility to edge cracking during forging of material hipped above the boride solvus is related to the boride morphology. Studies of the subsequent recrystallization of the forged samples have indicated that necklace formation is neither inhibited nor accelerated by the presence of grain boundary borides. 18 references.

  10. A matrix-inversion method for gamma-source mapping from gamma-count data - 59082

    International Nuclear Information System (INIS)

    Bull, Richard K.; Adsley, Ian; Burgess, Claire

    2012-01-01

    Gamma ray counting is often used to survey the distribution of active waste material in various locations. Ideally the output from such surveys would be a map of the activity of the waste. In this paper a simple matrix-inversion method is presented. This allows an array of gamma-count data to be converted to an array of source activities. For each survey area the response matrix is computed using the gamma-shielding code Microshield [1]. This matrix links the activity array to the count array. The activity array is then obtained via matrix inversion. The method was tested on artificially-created arrays of count-data onto which statistical noise had been added. The method was able to reproduce, quite faithfully, the original activity distribution used to generate the dataset. The method has been applied to a number of practical cases, including the distribution of activated objects in a hot cell and to activated Nimonic springs amongst fuel-element debris in vaults at a nuclear plant. (authors)

  11. In-place measurement of specific electric resistance during precipitation of γ'-precipitating Ni base alloys

    International Nuclear Information System (INIS)

    Silomon, M.

    1991-01-01

    During precipitation and coarsening of a second phase, the electric resistance of an alloy changes. Continuous resistance measurement is possible during heat treatment and can be conducted with limited experimental effort; any metallographic determination of the temperature and time dependencies of structural changes, however, requires very high effort. For this reason, an instrument was set up which permits continuous measurement of the resistance at precipitation temperature and during heating or cooling, while providing sufficient resolution for minor changes. Both measuring methods are conducted on technologically relevant alloys such as Nimonic PE 16 and those based on Ni-20 At.% Cr with deliberately varied additions of Al and Ti (accompanying investigations: TEM, SANS, and calorimetry). Their usefulness for alloy development is discussed within the scope of current concepts of demixing kinetics and resistance of alloys. Essential results concern the matrix/γ'-phase mismatch, the Ni 2 Cr short range order, and determination of the γ'-solvus temperature. (orig.) With 53 figs., 4 tabs [de

  12. Thermo-mechanical fatigue behaviour of the near-{gamma}-titanium aluminide alloy TNB-V5 under uniaxial and multiaxial loading

    Energy Technology Data Exchange (ETDEWEB)

    Brookes, Stephen Peter

    2009-12-19

    -strain history. The effects of TMF on the microstructure were also investigated. For all types of tests intergranular fracture is predominant. Failure is strongly influenced by environmental conditions. This study compares TMF results of TiAl with previous TMF investigations on the nickel-based alloys IN 738 and Nimonic 90. IN 738 shows similar TMF behaviour to {gamma}-TiAl in that uniaxial IP loading has the longest fatigue lifetimes. Nimonic 90 shows the opposite behaviour to both of these alloys. A lifetime model developed for this near-{gamma}-TiAl alloy, successfully describes all temperaturestrain TMF loading conditions over the test temperature range, with the use of a single loading parameter. The loading parameter is based on the plastic work per cycle, and is not only dependant on the mean tensile stress but also on the maximum principal stress. The loading parameter responds to various strain-temperature-paths differently. It describes the lifetime relation between uniaxial IP and OP loading, axial and torsional loading and the hold period effect. (orig.)

  13. Processing of Advanced Cast Alloys for A-USC Steam Turbine Applications

    Science.gov (United States)

    Jablonski, Paul D.; Hawk, Jeffery A.; Cowen, Christopher J.; Maziasz, Philip J.

    2012-02-01

    The high-temperature components within conventional supercritical coal-fired power plants are manufactured from ferritic/martensitic steels. To reduce greenhouse-gas emissions, the efficiency of pulverized coal steam power plants must be increased to as high a temperature and pressure as feasible. The proposed steam temperature in the DOE/NETL Advanced Ultra Supercritical power plant is high enough (760°C) that ferritic/martensitic steels will not work for the majority of high-temperature components in the turbine or for pipes and tubes in the boiler due to temperature limitations of this class of materials. Thus, Ni-based superalloys are being considered for many of these components. Off-the-shelf forged nickel alloys have shown good promise at these temperatures, but further improvements can be made through experimentation within the nominal chemistry range as well as through thermomechanical processing and subsequent heat treatment. However, cast nickel-based superalloys, which possess high strength, creep resistance, and weldability, are typically not available, particularly those with good ductility and toughness that are weldable in thick sections. To address those issues related to thick casting for turbine casings, for example, cast analogs of selected wrought nickel-based superalloys such as alloy 263, Haynes 282, and Nimonic 105 have been produced. Alloy design criteria, melt processing experiences, and heat treatment are discussed with respect to the as-processed and heat-treated microstructures and selected mechanical properties. The discussion concludes with the prospects for full-scale development of a thick section casting for a steam turbine valve chest or rotor casing.

  14. Processing of Advanced Alloys for A-USC Steam Turbine Applications

    Energy Technology Data Exchange (ETDEWEB)

    Jablonski, P. D. [National Energy Technology Laboratory (NETL); Hawk, Jeffrey A. [National Energy Technology Laboratory (NETL); Cowen, Christopher J. [National Energy Technology Laboratory (NETL); Maziasz, Philip J [ORNL

    2010-01-01

    The high-temperature components within conventional supercritical coal-fired power plants are manufactured from ferritic/martensitic steels. To reduce greenhouse-gas emissions, the efficiency of pulverized coal steam power plants must be increased to as high a temperature and pressure as feasible. The proposed steam temperature in the DOE/NETL Advanced Ultra Supercritical power plant is high enough (760 C) that ferritic/martensitic steels will not work for the majority of high-temperature components in the turbine or for pipes and tubes in the boiler due to temperature limitations of this class of materials. Thus, Ni-based superalloys are being considered for many of these components. Off-the-shelf forged nickel alloys have shown good promise at these temperatures, but further improvements can be made through experimentation within the nominal chemistry range as well as through thermomechanical processing and subsequent heat treatment. However, cast nickel-based superalloys, which possess high strength, creep resistance, and weldability, are typically not available, particularly those with good ductility and toughness that are weldable in thick sections. To address those issues related to thick casting for turbine casings, for example, cast analogs of selected wrought nickel-based superalloys such as alloy 263, Haynes 282, and Nimonic 105 have been produced. Alloy design criteria, melt processing experiences, and heat treatment are discussed with respect to the as-processed and heat-treated microstructures and selected mechanical properties. The discussion concludes with the prospects for full-scale development of a thick section casting for a steam turbine valve chest or rotor casing.

  15. Microstructural Evolution and Creep-Rupture Behavior of A-USC Alloy Fusion Welds

    Science.gov (United States)

    Bechetti, Daniel H.; DuPont, John N.; Siefert, John A.; Shingledecker, John P.

    2016-09-01

    Characterization of the microstructural evolution of fusion welds in alloys slated for use in advanced ultrasupercritical (A-USC) boilers during creep has been performed. Creep-rupture specimens involving INCONEL® 740, NIMONIC® 263 (INCONEL and NIMONIC are registered trademarks of Special Metals Corporation), and Haynes® 282® (Haynes and 282 are registered trademarks of Haynes International) have been analyzed via light optical microscopy, scanning electron microscopy, X-ray diffraction, and thermodynamic and kinetic modeling. Focus has been given to the microstructures that develop along the grain boundaries in these alloys during creep at temperatures relevant to the A-USC process cycle, and particular attention has been paid to any evidence of the formation of local γ'-denuded or γ'-free zones. This work has been performed in an effort to understand the microstructural changes that lead to a weld strength reduction factor (WSRF) in these alloys as compared to solution annealed and aged alloy 740 base metal. γ' precipitate-free zones have been identified in alloy 740 base metal, solution annealed alloy 740 weld metal, and alloy 263 weld metal after creep. Their development during long-term thermal exposure is correlated with the stabilization of phases that are rich in γ'-forming elements ( e.g., η and G) and is suppressed by precipitation of phases that do not contain the γ' formers ( e.g., M23C6 and μ). The location of failure and creep performance in terms of rupture life and WSRF for each welded joint is presented and discussed.

  16. Microstructure evolution of superalloy for large exhaust valve during hot forging

    International Nuclear Information System (INIS)

    Jeong, H.S.; Cho, J.R.; Park, H.C.

    2004-01-01

    The nickel-based alloy Nimonic 80A possesses strength, and corrosion, creep and oxidation resistance at high temperature. These products are used for aerospace, marine engineering and power generation, etc. The control of forging parameters such as strain, strain rate, temperature and holding time is important because the microstructure change in hot working affects the mechanical properties. It is necessary to understand the microstructure variation evolution. The microstructure change evolution occurs by recovery, recrystallization and grain growth phenomena. The dynamic recrystallization evolution has been studied in the temperature range 950-1250 deg. C and strain rate range 0.05-5s-1 using hot compression tests. The metadynamic recrystallization and grain growth evolution has been studied in the temperature range 950-1250 deg. C and strain rate range 0.05, 5s-1, holding time range 5, 10, 100, 600 sec using hot compression tests. Modeling equations are developed to represent the flow curve, recrystallized grain size, recrystallized fraction and grain growth phenomena by various tests. Parameters of modeling equation are expressed as a function of the Zener-Hollomon parameter. The modeling equation for grain growth is expressed as a function of initial grain size and holding time. The developed modeling equation was combined with thermo-viscoplastic finite element modeling to predict various microstructure change evolution during thermo mechanical processing. The predicted grain size in developed FE simulation results is compared with results obtained in various tests. In order to obtain a final microstructure and good mechanical properties in forging, the FEM would become a useful tool in the simulation of the microstructure development

  17. Materials for Advanced Ultrasupercritical Steam Turbines Task 4: Cast Superalloy Development

    Energy Technology Data Exchange (ETDEWEB)

    Thangirala, Mani

    2015-09-30

    The Steam Turbine critical stationary structural components are high integrity Large Shell and Valve Casing heavy section Castings, containing high temperature steam under high pressures. Hence to support the development of advanced materials technology for use in an AUSC steam turbine capable of operating with steam conditions of 760°C (1400°F) and 35 Mpa (5000 psia), Casting alloy selection and evaluation of mechanical, metallurgical properties and castability with robust manufacturing methods are mandated. Alloy down select from Phase 1 based on producability criteria and creep rupture properties tested by NETL-Albany and ORNL directed the consortium to investigate cast properties of Haynes 282 and Haynes 263. The goals of Task 4 in Phase 2 are to understand a broader range of mechanical properties, the impact of manufacturing variables on those properties. Scale up the size of heats to production levels to facilitate the understanding of the impact of heat and component weight, on metallurgical and mechanical behavior. GE Power & Water Materials and Processes Engineering for the Phase 2, Task 4.0 Castings work, systematically designed and executed casting material property evaluation, multiple test programs. Starting from 15 lbs. cylinder castings to world’s first 17,000 lbs. poured weight, heavy section large steam turbine partial valve Haynes 282 super alloy casting. This has demonstrated scalability of the material for steam Turbine applications. Activities under Task 4.0, Investigated and characterized various mechanical properties of Cast Haynes 282 and Cast Nimonic 263. The development stages involved were: 1) Small Cast Evaluation: 4 inch diam. Haynes 282 and Nimonic 263 Cylinders. This provided effects of liquidus super heat range and first baseline mechanical data on cast versions of conventional vacuum re-melted and forged Ni based super alloys. 2) Step block castings of 300 lbs. and 600 lbs. Haynes 282 from 2 foundry heats were evaluated which

  18. Phase Transformations in Cast Duplex Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yoon-Jun [Iowa State Univ., Ames, IA (United States)

    2004-01-01

    Duplex stainless steels (DSS) constitute both ferrite and austenite as a matrix. Such a microstructure confers a high corrosion resistance with favorable mechanical properties. However, intermetallic phases such as σ and χ can also form during casting or high-temperature processing and can degrade the properties of the DSS. This research was initiated to develop time-temperature-transformation (TTT) and continuous-cooling-transformation (CCT) diagrams of two types of cast duplex stainless steels, CD3MN (Fe-22Cr-5Ni-Mo-N) and CD3MWCuN (Fe-25Cr-7Ni-Mo-W-Cu-N), in order to understand the time and temperature ranges for intermetallic phase formation. The alloys were heat treated isothermally or under controlled cooling conditions and then characterized using conventional metallographic methods that included tint etching, and also using electron microscopy (SEM, TEM) and wavelength dispersive spectroscopy (WDS). The kinetics of intermetallic-phase (σ + χ) formation were analyzed using the Johnson-Mehl-Avrami (MA) equation in the case of isothermal transformations and a modified form of this equation in the case of continuous cooling transformations. The rate of intermetallic-phase formation was found to be much faster in CD3MWCuN than CD3MN due mainly to differences in the major alloying contents such as Cr, Ni and Mo. To examine in more detail the effects of these elements of the phase stabilities; a series of eight steel castings was designed with the Cr, Ni and Mo contents systematically varied with respect to the nominal composition of CD3MN. The effects of varying the contents of alloying additions on the formation of intermetallic phases were also studied computationally using the commercial thermodynamic software package, Thermo-Calc. In general, σ was stabilized with increasing Cr addition and χ by increasing Mo addition. However, a delicate balance among Ni and other minor elements such as N and Si also exists. Phase equilibria in DSS can be affected by

  19. Influence of thermal gradient on gas turbine combustor wall using impingement/effusion cooling techniques: CHT CFD predictions

    Directory of Open Access Journals (Sweden)

    A. M. El-jummah

    2017-04-01

    Full Text Available Internal wall heat transfer relevant to impingement/effusion cooling techniques was investigated using conjugate heat transfer (CHT computational fluid dynamics (CFD with ANSYS Fluent and ICEM commercial software. This work concentrates on the development of CHT CFD design procedures that are applicable to combustor wall and turbine blade heat transfer optimisation in gas turbine (GT. It specifically modelled and compares two configuration which are specifically relevant to the impingement and effusion holes density n (m-2 and is the ratio of the hole pitch X2. The configurations investigated are equal and unequal impingement and effusion holes density n (m-2, respectively, whereby in each case the variation in the number of cooling holes were carried out. The ratio of impingement and effusion number of holes/m2 (or hole density n, investigated were impingement/effusion: 4306/4306 and 1076/4306, respectively. The geometries were for impingement wall, hole pitch X to diameter D, X/D ratio of ~ 11 but different number of holes N for both n geometries, at a constant offset effusion wall, hole X/D of 4.7 of the same N for both the two configurations. The model geometries have a constant impingement gap of 8 mm with both impingement and effusion walls at 6.35 mm thick Nimonic - 75 material and were computed for varied air mass flux G from 0.1 - 0.94 kg/sm2. Symmetrical applications were employed in modelling each of the geometry, whereby for the impingement hole, only quarter of one hole was modelled, while for the effusion side the holes were either quarter or half modelled. The two n geometries were computed with k - ɛ turbulence model using standard wall functions, which also applies to all G. The predicted locally surface X2 (or hole square area average heat transfer coefficient (HTC h values compared with with previously published experimental data showed good agreement. The reduced internal gap flow recirculation with reduced heat transfer to

  20. Microstructural response to heat affected zone cracking of prewelding heat-treated Inconel 939 superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, M.A., E-mail: mgonzalez@comimsa.com.mx [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Martinez, D.I., E-mail: dorairma@yahoo.com [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Perez, A., E-mail: betinperez@hotmail.com [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Guajardo, H., E-mail: hguajardo@frisa.com [FRISA Aerospace, S.A. de C.V., Valentin G. Rivero No. 200, Col. Los Trevino, C.P. 66150, Santa Caterina N.L. (Mexico); Garza, A., E-mail: agarza@comimsa.com [Corporacion Mexicana de Investigacion en Materiales S.A. de C.V. (COMIMSA), Ciencia y Tecnologia No.790, Saltillo 400, C.P. 25295 Saltillo Coah. (Mexico)

    2011-12-15

    The microstructural response to cracking in the heat-affected zone (HAZ) of a nickel-based IN 939 superalloy after prewelding heat treatments (PWHT) was investigated. The PWHT specimens showed two different microstructures: 1) spherical ordered {gamma} Prime precipitates (357-442 nm), with blocky MC and discreet M{sub 23}C{sub 6} carbides dispersed within the coarse dendrites and in the interdendritic regions; and 2) ordered {gamma} Prime precipitates in 'ogdoadically' diced cube shapes and coarse MC carbides within the dendrites and in the interdendritic regions. After being tungsten inert gas welded (TIG) applying low heat input, welding speed and using a more ductile filler alloy, specimens with microstructures consisting of spherical {gamma} Prime precipitate particles and dispersed discreet MC carbides along the grain boundaries, displayed a considerably improved weldability due to a strong reduction of the intergranular HAZ cracking associated with the liquation microfissuring phenomena. - Highlights: Black-Right-Pointing-Pointer Homogeneous microstructures of {gamma} Prime spheroids and discreet MC carbides of Ni base superalloys through preweld heat treatments. Black-Right-Pointing-Pointer {gamma} Prime spheroids and discreet MC carbides reduce the intergranular HAZ liquation and microfissuring of Nickel base superalloys. Black-Right-Pointing-Pointer Microstructure {gamma} Prime spheroids and discreet blocky type MC carbides, capable to relax the stress generated during weld cooling. Black-Right-Pointing-Pointer Low welding heat input welding speeds and ductile filler alloys reduce the HAZ cracking susceptibility.

  1. Microstructural Evolution and Creep-Rupture Behavior of Fusion Welds Involving Alloys for Advanced Ultrasupercritical Power Generation

    Science.gov (United States)

    Bechetti, Daniel H., Jr.

    Projections for large increases in the global demand for electric power produced by the burning of fossil fuels, in combination with growing environmental concerns surrounding these fuel sources, have sparked initiatives in the United States, Europe, and Asia aimed at developing a new generation of coal fired power plant, termed Advanced Ultrasupercritical (A-USC). These plants are slated to operate at higher steam temperatures and pressures than current generation plants, and in so doing will offer increased process cycle efficiency and reduced greenhouse gas emissions. Several gamma' precipitation strengthened Ni-based superalloys have been identified as candidates for the hottest sections of these plants, but the microstructural instability and poor creep behavior (compared to wrought products) of fusion welds involving these alloys present significant hurdles to their implementation and a gap in knowledge that must be addressed. In this work, creep testing and in-depth microstructural characterization have been used to provide insight into the long-term performance of these alloys. First, an investigation of the weld metal microstructural evolution as it relates to creep strength reductions in A-USC alloys INCONELRTM 740, NIMONICRTM 263 (INCONEL and NIMONIC are registered trademarks of Special Metals Corporation), and HaynesRTM 282RTM (Haynes and 282 are registered trademarks of Haynes International) was performed. gamma'-precipitate free zones were identified in two of these three alloys, and their development was linked to the evolution of phases that precipitate at the expense of gamma'. Alloy 282 was shown to avoid precipitate free zone formation because the precipitates that form during long term aging in this alloy are poor in the gamma'-forming elements. Next, the microstructural evolution of INCONELRTM 740H (a compositional variant of alloy 740) during creep was investigated. Gleeble-based interrupted creep and creep-rupture testing was used to

  2. Experimental Design for Evaluation of Co-extruded Refractory Metal/Nickel Base Superalloy Joints

    International Nuclear Information System (INIS)

    ME Petrichek

    2005-01-01

    Prior to the restructuring of the Prometheus Program, the NRPCT was tasked with delivering a nuclear space reactor. Potential NRPCT nuclear space reactor designs for the Prometheus Project required dissimilar materials to be in contact with each other while operating at extreme temperatures under irradiation. As a result of the high reactor core temperatures, refractory metals were the primary candidates for many of the reactor structural and cladding components. They included the tantalum-base alloys ASTAR-811C and Ta-10W, the niobium-base alloy FS-85, and the molybdenum base alloys Moly 41-47.5 Rhenium. The refractory metals were to be joined to candidate nickel base alloys such as Haynes 230, Alloy 617, or Nimonic PE 16 either within the core if the nickel-base alloys were ultimately selected to form the outer core barrel, or at a location exterior to the core if the nickel-base alloys were limited to components exterior to the core. To support the need for dissimilar metal joints in the Prometheus Project, a co-extrusion experiment was proposed. There are several potential methods for the formation of dissimilar metal joints, including explosive bonding, friction stir welding, plasma spray, inertia welding, HIP, and co-extrusion. Most of these joining methods are not viable options because they result in the immediate formation of brittle intermetallics. Upon cooling, intermetallics form in the weld fusion zone between the joined metals. Because brittle intermetallics do not form during the initial bonding process associated with HIP, co-extrusion, and explosive bonding, these three joining procedures are preferred for forming dissimilar metal joints. In reference to a Westinghouse Astronuclear Laboratory report done under a NASA sponsored program, joints that were fabricated between similar materials via explosive bonding had strengths that were directly affected by the width of the diffusion barrier. It was determined that the diffusion zone should not exceed

  3. Development and Validation of a Preprocedural Risk Score to Predict Access Site Complications After Peripheral Vascular Interventions Based on the Vascular Quality Initiative Database

    Directory of Open Access Journals (Sweden)

    Daniel Ortiz

    2016-01-01

    Full Text Available Purpose: Access site complications following peripheral vascular intervention (PVI are associated with prolonged hospitalization and increased mortality. Prediction of access site complication risk may optimize PVI care; however, there is no tool designed for this. We aimed to create a clinical scoring tool to stratify patients according to their risk of developing access site complications after PVI. Methods: The Society for Vascular Surgery’s Vascular Quality Initiative database yielded 27,997 patients who had undergone PVI at 131 North American centers. Clinically and statistically significant preprocedural risk factors associated with in-hospital, post-PVI access site complications were included in a multivariate logistic regression model, with access site complications as the outcome variable. A predictive model was developed with a random sample of 19,683 (70% PVI procedures and validated in 8,314 (30%. Results: Access site complications occurred in 939 (3.4% patients. The risk tool predictors are female gender, age > 70 years, white race, bedridden ambulatory status, insulin-treated diabetes mellitus, prior minor amputation, procedural indication of claudication, and nonfemoral arterial access site (model c-statistic = 0.638. Of these predictors, insulin-treated diabetes mellitus and prior minor amputation were protective of access site complications. The discriminatory power of the risk model was confirmed by the validation dataset (c-statistic = 0.6139. Higher risk scores correlated with increased frequency of access site complications: 1.9% for low risk, 3.4% for moderate risk and 5.1% for high risk. Conclusions: The proposed clinical risk score based on eight preprocedural characteristics is a tool to stratify patients at risk for post-PVI access site complications. The risk score may assist physicians in identifying patients at risk for access site complications and selection of patients who may benefit from bleeding avoidance

  4. Persistent organic pollutants in early pregnancy and risk of gestational diabetes mellitus.

    Science.gov (United States)

    Vafeiadi, Marina; Roumeliotaki, Theano; Chalkiadaki, Georgia; Rantakokko, Panu; Kiviranta, Hannu; Fthenou, Eleni; Kyrtopoulos, Soterios A; Kogevinas, Manolis; Chatzi, Leda

    2017-01-01

    Persistent organic pollutants (POPs) are a group of diverse substances, including polychlorinated biphenyls (PCBs) and organochlorine pesticides that are resistant to biodegradation and ubiquitously present in our environment. Exposure to endocrine disrupting chemicals such as POPs has been linked to type 2 diabetes and metabolic disturbances in epidemiological and animal studies, but little is known about POPs exposure during pregnancy and the development of gestational diabetes mellitus (GDM). The purpose of this study was to determine the extent to which exposure to current low levels of different POPs in the first trimester of pregnancy is associated with GDM risk in 939 women from the "Rhea" pregnancy cohort in Crete, Greece. Concentrations of several PCBs, dichlorodiphenyldichloroethene (DDE), and hexachlorobenzene (HCB) were determined in first trimester maternal serum by triple quadrupole mass spectrometry. We defined total PCBs as the sum of all congeners, nondioxin-like PCBs as the sum of PCB 153, 138, 170 and 180, and dioxin-like PCBs as the sum of PCB 118 and 156. Pregnant women were screened for gestational diabetes mellitus (GDM) between 24 and 28weeks of gestation, and GDM was defined by the criteria proposed by Carpenter and Coustan. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression models. Of the 939 women, 68 (7%) developed GDM. Serum concentrations of POPs were higher in women with GDM. Women in the medium and high tertiles of PCBs had 3.90 (95% CI: 1.37, 11.06) and 3.60 (95% CI: 1.14, 11.39) fold respectively higher odds of developing GDM compared to women in the lowest tertile of PCB exposure after adjusting for pre-pregnancy BMI and several other confounders. Odds of GDM for women in the medium and high tertiles of dioxin-like PCBs was 5.63 (95% CI: 1.81, 17.51) and 4.71 (95% CI: 1.38, 16.01) and for nondioxin-like PCBs 2.36 (95% CI: 0.89, 6.23) and 2.26 (95% CI: 0.77, 6

  5. Bloodstream Amyloid-beta (1-40) Peptide, Cognition, and Outcomes in Heart Failure.

    Science.gov (United States)

    Bayes-Genis, Antoni; Barallat, Jaume; de Antonio, Marta; Domingo, Mar; Zamora, Elisabet; Vila, Joan; Subirana, Isaac; Gastelurrutia, Paloma; Pastor, M Cruz; Januzzi, James L; Lupón, Josep

    2017-11-01

    In the brain, amyloid-beta generation participates in the pathophysiology of cognitive disorders; in the bloodstream, the role of amyloid-beta is uncertain but may be linked to sterile inflammation and senescence. We explored the relationship between blood levels of amyloid-beta 1-40 peptide (Aβ40), cognition, and mortality (all-cause, cardiovascular, and heart failure [HF]-related) in ambulatory patients with HF. Bloodstream Aβ40 was measured in 939 consecutive patients with HF. Cognition was evaluated with the Pfeiffer questionnaire (adjusted for educational level) at baseline and during follow-up. Multivariate Cox regression analyses and measurements of performance (discrimination, calibration, and reclassification) were used, with competing risk for specific causes of death. Over 5.1 ± 2.9 years, 471 patients died (all-cause): 250 from cardiovascular causes and 131 HF-related. The median Aβ40 concentration was 519.1 pg/mL [Q1-Q3: 361.8-749.9 pg/mL]. The Aβ40 concentration correlated with age, body mass index, renal dysfunction, and New York Heart Association functional class (all P < .001). There were no differences in Aβ40 in patients with and without cognitive impairment at baseline (P = .97) or during follow-up (P = .20). In multivariable analysis, including relevant clinical predictors and N-terminal pro-B-type natriuretic peptide, Aβ40 remained significantly associated with all-cause death (HR, 1.22; 95%CI, 1.10-1.35; P < .001) and cardiovascular death (HR, 1.18; 95%CI, 1.03-1.36; P = .02), but not with HF-related death (HR, 1.13; 95%CI, 0.93-1.37; P = .22). Circulating Aβ40 improved calibration and patient reclassification. Blood levels of Aβ40 are not associated with cognitive decline in HF. Circulating Aβ40 was predictive of mortality and may indicate systemic aging. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  6. Follow-up study of the WHO-Global Campaign Against Epilepsy Demonstration Project in rural China after four years of its terminati

    Directory of Open Access Journals (Sweden)

    YANG Hong-chao

    2012-10-01

    Full Text Available Objective To follow up the outcome of 2455 patients with epilepsy (the cohort treated by phenobarbital (PB during the WHO-Global Campaign Against Epilepsy Demonstration Project (GCAE/DP in rural China after 4 years of its termination, to provide practical evidence for community control of epilepsy in rural China. Methods In 2008, the trained local township physicians, using a well-designed questionnaire, by door-to-door interview, followed up the cohort residents in 8 counties of 6 provinces where the GCAE/DP was conducted and completed for 4 years. Results One thousand seven hundred and eighty of the 2455 patients were visited in the follow-up study. Nine hundred and thirty-nine (52.75% were still taking PB, the effectiveness rates (seizure free and seizure frequency reduced > 50% among them at 12, 24, 36, 48 months after the GCAE/DP were 66.77% (627/939, 68.37% (642/939, 71.35% (670/939, 73.06% (686/939, respectively. In 841 patients (47.25% who stopped taking PB, 244 cases (29.01% were seizure free, 320 (38.05% still had seizures but discontinued the treatment, 277 (32.94% were treated by other antiepileptic drugs (AEDs. Chi-square test was used to compare the therapeutic effectiveness in 939 patients continuing taking PB and 841 patients abandoning PB. Patients continuing taking PB had a better outcome than patients abandoning PB (χ2 = 12.423, P = 0.002. The main reasons of PB withdrawal were seizure free (29.01%, taking other AEDs (32.94%, no free drug or no money (11.06%, effect was not good or PB was not available (6.42% . Two hundred and six patients died between 2002 and 2008. The standardized mortality ratio (SMR for the cohort was 19.10. The three leading causes of death were: accidents (n = 59, 28.64% , cerebrovascular diseases (n = 30, 14.56% and status epilepticus (n = 28, 13.59%. Conclusion The GCAE/DP was successful and with long term good results, so it is worthy for further promotion. The mortality rate was very high in the

  7. Karakterizacija vakuum plazma naprskane kobalt-nikal-hrom-aluminijum-itrijum prevlake

    Directory of Open Access Journals (Sweden)

    Mihailo R. Mrdak

    2013-12-01

    prevlake za ispitivanje mikrotvrdoće i za procenu mikrostrukture u deponovanom stanju su napravljene od čelika Č.4171 (X15Cr13 EN10027 u termički neobrađenom stanju dimenzija 70x20x1,5mm (Turbojet Engine - Standard Practices Manual (PN 582005, 2002, Pratt & Whitney, East Hartford, USA. Uzorci za ispitivanje mikrostrukture prevlake na oksidaciju na 1100°C su napravljeni od legure NIMONIC 80A dimenzija 70x20x1,5mm (Turbojet Engine - Standard Practices Manual (PN 582005, 2002, Pratt & Whitney, East Hartford, USA. Osnove za ispitivanje čvrstoće spoja su takođe napravljene od čelika Č.4171(X15Cr13EN10027 u termički neobrađenom stanju dimenzija Ø25x50 mm (Turbojet Engine - Standard Practices Manual (PN 582005, 2002, Pratt & Whitney, East Hartford, USA. Ispitivanje mikrotvrdoće,čvrstoće spoja i mikrostrukture Procena mehaničkih osobina slojeva je urađena ispitivanjem mikrotvrdoće metodom HV0.3 i čvrstoće spoja ispitivanjem na zatezanje. Merenje mikrotvrdoće je izvršeno u pravcu duž lamela, u sredini i na krajevima uzoraka. Izvršeno je pet očitavanja vrednosti, koje su usrednjene. Metoda ispitivanja čvrstoće spoja je metoda ispitivanja na zatezanje. Ispitivanje je urađeno na sobnoj temperaturi sa brzinom zatezanja 1cm/60s. Za svaku grupu uzoraka su ispitane po tri epruvete. Morfologija čestica praha urađena je metodom SEM. Mikrostruktura slojeva u deponovanom stanju posle nagrizanja je ispitana tehnikom svetlosne mikroskopije. Prevlaka najboljih mehaničkih karakteristika, koja je termički tretirana na oksidaciju na 1100°C u trajanju od 240 sati ispitana je na skening elektronskom mikroskopu (SEM. Nagrizanje prevlake je rađeno elektrolitički sa 10% oksalne kiseline H2C2O4 x2H2O. Depozicija praha Depozicija praha izvršena je na niskom pritisku u vakuumu sa mešavinom plazma-gasova Ar-H2. Vakuum plazma sprej (VPS sistem firme Plasma Technik AG je projektovan za zaštitu vazduhoplovnh delova izloženih kombinaciji prekomerne oksidacije i vrele