Microstructure, Lattice Misfit, and High-Temperature Strength of γ'-Strengthened Co-Al-W-Ge Model Superalloys

Science.gov (United States)

Zenk, Christopher H.; Bauer, Alexander; Goik, Philip; Neumeier, Steffen; Stone, Howard J.; Göken, Mathias

2016-05-01

The quaternary alloy system Co-Al-W-Ge was investigated and it was found that a continuous γ /γ ^' two-phase field extends between the systems Co-Al-W and Co-Ge-W. All alloys examined comprised cuboidal L1_2 precipitates coherently embedded in an A1 matrix. Differential scanning calorimetry measurements revealed that the liquidus, solidus, and γ ^' -solvus temperatures decrease when the Ge content is increased. The lower liquidus temperature and the capability of γ ^' -strengthening in the Ge-rich alloys make them interesting as potential candidates for brazing applications of Co-base superalloys. The γ /γ ^' lattice misfit was determined by high-resolution X-ray diffraction and found to be positive for all alloys investigated, decreasing with increasing Ge content. The mechanical properties of the Al-rich alloys surpass those rich in Ge.

The High Temperature Tensile and Creep Behaviors of High Entropy Superalloy.

Science.gov (United States)

Tsao, Te-Kang; Yeh, An-Chou; Kuo, Chen-Ming; Kakehi, Koji; Murakami, Hideyuki; Yeh, Jien-Wei; Jian, Sheng-Rui

2017-10-04

This article presents the high temperature tensile and creep behaviors of a novel high entropy alloy (HEA). The microstructure of this HEA resembles that of advanced superalloys with a high entropy FCC matrix and L1 2 ordered precipitates, so it is also named as "high entropy superalloy (HESA)". The tensile yield strengths of HESA surpass those of the reported HEAs from room temperature to elevated temperatures; furthermore, its creep resistance at 982 °C can be compared to those of some Ni-based superalloys. Analysis on experimental results indicate that HESA could be strengthened by the low stacking-fault energy of the matrix, high anti-phase boundary energy of the strengthening precipitate, and thermally stable microstructure. Positive misfit between FCC matrix and precipitate has yielded parallel raft microstructure during creep at 982 °C, and the creep curves of HESA were dominated by tertiary creep behavior. To the best of authors' knowledge, this article is the first to present the elevated temperature tensile creep study on full scale specimens of a high entropy alloy, and the potential of HESA for high temperature structural application is discussed.

Microstructural analysis of laser weld fusion zone in Haynes 282 superalloy

Energy Technology Data Exchange (ETDEWEB)

Osoba, L.O. [Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, Manitoba, R3T 5V6 (Canada); Ding, R.G. [Department of Metallurgy and Materials Engineering, University of Birmingham, Birmingham B15 2TT (United Kingdom); Ojo, O.A., E-mail: ojo@cc.umanitoba.ca [Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, Manitoba, R3T 5V6 (Canada)

2012-03-15

Analytical electron microscopy and spectroscopy analyses of the fusion zone (FZ) microstructure in autogenous laser beam welded Haynes 282 (HY 282) superalloy were performed. The micro-segregation patterns observed in the FZ indicate that Co, Cr and Al exhibited a nearly uniform distribution between the dendrite core and interdendritic regions while Ti and Mo were rejected into the interdendritic liquid during the weld solidification. Transmission electron diffraction analysis and energy dispersive X-ray microanalysis revealed the second phase particles formed along the FZ interdendritic region to be Ti-Mo rich MC-type carbide particles. Weld FZ solidification cracking, which is sometimes associated with the formation of {gamma}-{gamma}' eutectic in {gamma}' precipitation strengthened nickel-base superalloys, was not observed in the HY 282 superalloy. Modified primary solidification path due to carbon addition in the newly developed superalloy is used to explain preclusion of weld FZ solidification cracking in the material. - Highlights: Black-Right-Pointing-Pointer A newly developed superalloy was welded by CO{sub 2} laser beam joining technique. Black-Right-Pointing-Pointer Electron microscopy characterization of the weld microstructure was performed. Black-Right-Pointing-Pointer Identified interdendritic microconstituents consist of MC-type carbides. Black-Right-Pointing-Pointer Modification of primary solidification path is used to explain cracking resistance.

Microstructural analysis of laser weld fusion zone in Haynes 282 superalloy

International Nuclear Information System (INIS)

Osoba, L.O.; Ding, R.G.; Ojo, O.A.

2012-01-01

Analytical electron microscopy and spectroscopy analyses of the fusion zone (FZ) microstructure in autogenous laser beam welded Haynes 282 (HY 282) superalloy were performed. The micro-segregation patterns observed in the FZ indicate that Co, Cr and Al exhibited a nearly uniform distribution between the dendrite core and interdendritic regions while Ti and Mo were rejected into the interdendritic liquid during the weld solidification. Transmission electron diffraction analysis and energy dispersive X-ray microanalysis revealed the second phase particles formed along the FZ interdendritic region to be Ti–Mo rich MC-type carbide particles. Weld FZ solidification cracking, which is sometimes associated with the formation of γ–γ' eutectic in γ' precipitation strengthened nickel-base superalloys, was not observed in the HY 282 superalloy. Modified primary solidification path due to carbon addition in the newly developed superalloy is used to explain preclusion of weld FZ solidification cracking in the material. - Highlights: ► A newly developed superalloy was welded by CO 2 laser beam joining technique. ► Electron microscopy characterization of the weld microstructure was performed. ► Identified interdendritic microconstituents consist of MC-type carbides. ► Modification of primary solidification path is used to explain cracking resistance.

Recrystallization of the ODS superalloy PM-1000

International Nuclear Information System (INIS)

Sandim, H.R.Z.; Hayama, A.O.F.; Raabe, D.

2006-01-01

The primary recrystallization of a -fiber textured coarse-grained oxide dispersion strengthened nickel-based superalloy (PM-1000) has been investigated by high-resolution electron backscatter diffraction. The annealing behavior of this alloy is quite complex. Even at high annealing temperatures (e.g. 1200 deg. C), recrystallization is only partial. The microstructure of this superalloy in the annealed state consists of a blurred subgrain structure, coarse grains with sizes of about 10-20 μm at the pre-existing grain boundaries and a significant fraction of small crystals in the interior of the recovered grains. These small grains are elongated and display anisotropic growth. In the present paper we present a detailed explanation for this peculiar microstructure. Particular focus is placed on the origin of the new grains in the recovered structure in a [1 0 0]-oriented grain

Mechanical Behavior of Three-Dimensional Braided Nickel-Based Superalloys Synthesized via Pack Cementation

Science.gov (United States)

Lippitz, Nicolas; Erdeniz, Dinc; Sharp, Keith W.; Dunand, David C.

2018-03-01

Braided tubes of Ni-based superalloys are fabricated via three-dimensional (3-D) braiding of ductile Ni-20Cr (wt pct) wires followed by post-textile gas-phase alloying with Al and Ti to create, after homogenization and aging, γ/ γ' strengthened lightweight, porous structures. Tensile tests reveal an increase in strength by 100 MPa compared to as-braided Ni-20Cr (wt pct). An interrupted tensile test, combined with X-ray tomographic scans between each step, sheds light on the failure behavior of the braided superalloy tubes.

Microstructure and Mechanical Properties in Gamma(face-centered cubic) + Gamma Prime(L12) Precipitation-Strengthened Cobalt-based Superalloys

Science.gov (United States)

Bocchini, Peter J.

High-temperature structural alloys for aerospace and energy applications have long been dominated by Ni-based superalloys, whose high-temperature strength and creep resistance can be attributed to a two-phase microstructure consisting of a large volume fraction of ordered gamma'(L12)-precipitates embedded in a disordered gamma(f.c.c.)-matrix. These alloys exhibit excellent mechanical behavior and thermal stability, but after decades of incremental improvement, are nearing the theoretical limit of their operating temperatures. In 2006, an analogous gamma(f.c.c.) + gamma'(L12) microstructure was identified in the Co-Al-W ternary system with liquidus and solidus temperatures 50-150 °C higher than conventional Ni-based superalloys. The work herein focuses on assessing the effects of alloying additions on microstructure and mechanical behavior in an effort to lay the foundations for understanding this emerging alloy system. A variety of Co-based superalloys are investigated in order to study fundamental materials properties and to address key engineering challenges. Coarsening rate constants and temporal exponents are measured for gamma'(L1 2)-precipitates in a ternary Co-Al-W alloy aged at 650 °C and 750 °C. A series of Co-Al-W-B-Zr alloys are cast to study the influence of segregation of B and Zr to grain boundaries (GBs) on mechanical properties. Co-Ni-Al-W-Ti alloys with various amounts of Al, W, and Ti are cast in order to fabricate Co-based superalloys with decreased density and increased gamma'(L1 2)-solvus temperature. 2-D dislocation dynamics modeling is employed to predict how gamma'(L12)-precipitate size and volume fraction affect the mechanical properties of Ni- and Co-based superalloys. Compositional information such as phase concentrations, partitioning behavior, and GB segregation are measured with local electrode atom probe (LEAP) tomography in alloys with fine microstructures and with scanning electron microscope (SEM) electron dispersive x

High temperature properties of polycrystalline γ{sup '}-strengthened cobalt-base superalloys; Hochtemperatureigenschaften polykristalliner γ{sup '}-gehaerteter Kobaltbasis-Superlegierungen

Energy Technology Data Exchange (ETDEWEB)

Bauer, Alexander

2016-07-01

The recent discovery of a stable γ{sup '}-phase in Co-based superalloys opened up a pathway for the development of a new high temperature material class, which is similar in microstructure and properties to the modern γ{sup '}-hardened Ni-based superalloys. In this work, the first attempt was done to check the influence of several for Ni-based superalloys typical alloying elements on the properties of the new Co-based superalloys. It became clear that the basic characteristics of the first experimental alloys are similar to those of the γ{sup '}-hardened Ni-based alloys. The results of the multinary experimental alloys show that, based on the insight gained so far, targeted alloy development is possible. These materials have the potential to be used as disc materials in turbines.

Computational and Experimental Design of Fe-Based Superalloys for Elevated-Temperature Applications

Energy Technology Data Exchange (ETDEWEB)

Liaw, Peter K. [Univ. of Tennessee, Knoxville, TN (United States); Fine, Morris E. [Northwestern Univ., Evanston, IL (United States); Ghosh, Gautam [Northwestern Univ., Evanston, IL (United States); Asta, Mark D. [Univ. of California, Berkeley, CA (United States); Liu, Chain T. [Auburn Univ., AL (United States); Sun, Zhiqian [Univ. of Tennessee, Knoxville, TN (United States); Huang, Shenyan [Univ. of Tennessee, Knoxville, TN (United States); Teng, Zhenke [Univ. of Tennessee, Knoxville, TN (United States); Wang, Gongyao [Univ. of Tennessee, Knoxville, TN (United States)

2012-04-13

Analogous to nickel-based superalloys, Fe-based superalloys, which are strengthened by coherent B2- type precipitates are proposed for elevated-temperature applications. During the period of this project, a series of ferritic superalloys have been designed and fabricated by methods of vacuum-arc melting and vacuum-induction melting. Nano-scale precipitates were characterized by atom-probe tomography, ultrasmall- angle X-ray scattering, and transmission-electron microscopy. A duplex distribution of precipitates was found. It seems that ferritic superalloys are susceptible to brittle fracture. Systematic endeavors have been devoted to understanding and resolving the problem. Factors, such as hot rolling, precipitate volume fractions, alloy compositions, precipitate sizes and inter-particle spacings, and hyperfine cooling precipitates, have been investigated. In order to understand the underlying relationship between the microstructure and creep behavior of ferric alloys at elevated temperatures, in-situ neutron studies have been carried out. Based on the current result, it seems that the major role of β' with a 16%-volume fraction in strengthening ferritic alloys is not load sharing but interactions with dislocations. The oxidation behavior of one ferritic alloy, FBB8 (Fe-6.5Al-10Ni-10Cr-3.4Mo-0.25Zr-0.005B, weight percent), was studied in dry air. It is found that it possesses superior oxidation resistance at 1,023 and 1,123 K, compared with other creep-resistant ferritic steels [T91 (modified 9Cr-1Mo, weight percent) and P92 (9Cr-1.8W-0.5Mo, weight percent)]. At the same time, the calculation of the interfacial energies between the -iron and B2-type intermetallics (CoAl, FeAl, and NiAl) has been conducted.

Intermediate Co/Ni-base model superalloys — Thermophysical properties, creep and oxidation

International Nuclear Information System (INIS)

Zenk, Christopher H.; Neumeier, Steffen; Engl, Nicole M.; Fries, Suzana G.; Dolotko, Oleksandr; Weiser, Martin; Virtanen, Sannakaisa; Göken, Mathias

2016-01-01

The mechanical properties of γ′-strengthened Co–Ni–Al–W–Cr model superalloys extending from pure Ni-base to pure Co-base superalloys have been assessed. Differential scanning calorimetry measurements and thermodynamic calculations match well and show that the γ′ solvus temperature decreases with increasing Co-content. The γ/γ′ lattice misfit is negative on the Ni- and positive on the Co-rich side. High Ni-contents decelerate the oxidation kinetics up to a factor of 15. The creep strength of the Ni-base alloy increases by an order of magnitude with additions of Co before it deteriorates strongly upon higher additions despite an increasing γ′ volume fraction.

Modeling Long-term Creep Performance for Welded Nickel-base Superalloy Structures for Power Generation Systems

Energy Technology Data Exchange (ETDEWEB)

Shen, Chen [GE Global Research, NIskayuna, NY (United States); Gupta, Vipul [GE Global Research, NIskayuna, NY (United States); Huang, Shenyan [GE Global Research, NIskayuna, NY (United States); Soare, Monica [GE Global Research, NIskayuna, NY (United States); Zhao, Pengyang [GE Global Research, NIskayuna, NY (United States); Wang, Yunzhi [GE Global Research, NIskayuna, NY (United States)

2017-02-28

The goal of this project is to model long-term creep performance for nickel-base superalloy weldments in high temperature power generation systems. The project uses physics-based modeling methodologies and algorithms for predicting alloy properties in heterogeneous material structures. The modeling methodology will be demonstrated on a gas turbine combustor liner weldment of Haynes 282 precipitate-strengthened nickel-base superalloy. The major developments are: (1) microstructure-property relationships under creep conditions and microstructure characterization (2) modeling inhomogeneous microstructure in superalloy weld (3) modeling mesoscale plastic deformation in superalloy weld and (4) a constitutive creep model that accounts for weld and base metal microstructure and their long term evolution. The developed modeling technology is aimed to provide a more efficient and accurate assessment of a material’s long-term performance compared with current testing and extrapolation methods. This modeling technology will also accelerate development and qualification of new materials in advanced power generation systems. This document is a final technical report for the project, covering efforts conducted from October 2014 to December 2016.

Welding Metallurgy of Nickel-Based Superalloys for Power Plant Construction

Science.gov (United States)

Tung, David C.

Increasing the steam temperature and pressure in coal-fired power plants is a perpetual goal driven by the pursuit of increasing thermal cycle efficiency and reducing fuel consumption and emissions. The next target steam operating conditions, which are 760°C (1400°F) and 35 MPa (5000 psi) are known as Advanced Ultra Supercritical (AUSC), and can reduce CO2 emissions up to 13% but this cannot be achieved with traditional power plant construction materials. The use of precipitation-strengthened Nickel-based alloys (superalloys) is required for components which will experience the highest operating temperatures. The leading candidate superalloys for power plant construction are alloys 740H, 282, and 617. Superalloys have excellent elevated temperature properties due to careful microstructural design which is achieved through very specific heat treatments, often requiring solution annealing or homogenization at temperatures of 1100 °C or higher. A series of postweld heat treatments was investigated and it was found that homogenization steps before aging had no noticeable effect on weld metal microhardness, however; there were clear improvements in weld metal homogeneity. The full abstract can be viewed in the document itself.

Microstructural investigation of thermally aged nickel-based superalloy 718Plus

International Nuclear Information System (INIS)

Whitmore, Lawrence; Ahmadi, Mohammad Reza; Stockinger, Martin; Povoden-Karadeniz, Erwin; Kozeschnik, Ernst; Leitner, Harald

2014-01-01

The effects of thermal aging upon the nickel-based 718Plus superalloy are investigated and modelled. Yield strength and micro-hardness measurements are made after solution annealing and after aging at 788 °C for 4 h. In order to explain the differences in strength and hardness, a detailed investigation of the microstructure is performed using transmission electron microscopy. The size and phase fraction of the γ′ precipitates are measured and related to the measured hardness and yield strength using a theoretical model of precipitation strengthening based on the shearing of precipitates in terms of coherency strengthening and the formation of an antiphase boundary

On the microstructural origin of primary creep in nickel-base superalloys

International Nuclear Information System (INIS)

Heilmaier, M.; Reppich, B.

1997-01-01

The nature of primary creep in nickel-base superalloys is strongly correlated to the different hardening species present in the material. In fine-grained single-phase material the classical assumption of a homogeneous dislocation distribution enables the prediction of the transition from normal via sigmoidal to inverse primary creep with decreasing applied stress σ. In coarse-grained material the back stress σ b of hard subgrain boundaries evolving during plastic deformation must be additionally taken into account. Second-phase particles influence creep in a 2-fold manner via reducing the effective stress σ eff , namely directly by the stress σ p * for particle overcoming, and indirectly by increasing the dislocation density ρ. The proposed approach accounts for the observed pronounced normal primary creep in particle-strengthened superalloys. (orig.)

Development of advanced P/M Ni-base superalloys for turbine disks

Directory of Open Access Journals (Sweden)

Garibov Genrikh S.

2014-01-01

Full Text Available In the process of evolution of powder metallurgy in Russia the task permanently formulated was the following: to improve strength properties of P/M superalloys without application of additional complex HIPed blanks deformation operation. On the other hand development of a turbine disk material structure to ensure an improvement in aircraft engine performance requires the use of special HIP and heat treatment conditions. To ensure maximum strength properties of disk materials it is necessary to form a structure which would have optimum size of solid solution grains, γ′-phases and carbides. Along with that heating of the material up to a temperature determined by solvus of an alloy ensures a stable and reproducible level of mechanical properties of the disks. The above-said can be illustrated by successful mastering of new complex-alloyed VVP-class superalloys with the use of powder size − 100 μm. Application of special HIP and heat treatment conditions for these superalloys to obtain the desired grain size and the strengthening γ′-phase precipitates allowed a noticeable improvement in ultimate tensile strength and yield strength up to ≥1600 MPa and ≥1200 MPa respectively. 100 hrs rupture strength at 650 ∘C and 750 ∘C was improved up to 1140 MPa and 750 MPa respectively. P/M VVP nickel-base superalloys offer higher characteristics in comparison with many superalloys designed for the same purposes. HIPed disc compacts manufactured from PREP-powder have a homogeneous micro- and macrostructure, a stable level of mechanical properties.

Analysis of microstructure in electro-spark deposited IN718 superalloy

Energy Technology Data Exchange (ETDEWEB)

Anisimov, E.; Khan, A.K.; Ojo, O.A., E-mail: olanrewaju.ojo@umanitoba.ca

2016-09-15

The microstructure of electro-spark deposited (ESD) superalloy IN718 was studied by the use of scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. In converse to general assumption, the extremely high cooling rate involved in the ESD process did not produce partitionless solidification that is devoid of second phase microconstituents in the material, nano-sized Laves phase and MC carbide particles were observed within the deposited layer. Notwithstanding the several thermal cycles involved in the process, the extremely low heat input of the process produced a deposited region that is free of the main strengthening phase of the alloy, γ″ phase precipitates, which is in contrast to what have been reported on laser deposition. Nevertheless, application of the standard full heat treatment of the alloy resulted in extensive formation of the γ″ phase precipitates and δ phase precipitates, the most stable secondary phase of the alloy, with nearly, if not complete, dissolution of the Laves phase particles. Furthermore, the XPS analysis done in the study revealed the formation of nano-oxides within the deposited layer, which increased the microhardness of the superalloy in the as-deposited condition and inhibited its grain growth during post-process heat treatment. The microstructure analysis done in this work is crucial to the understanding of properties of the superalloy processed by the ESD technique. - Highlights: •Electron microscopy analyses of electro-spark deposited IN 718 superalloy were performed. •Nano-sized secondary phase particles were observed within the deposited layer. •The study shows that the ESD did not produce partitionless solidification of the alloy.

Computational Design of Creep-Resistant Alloys and Experimental Validation in Ferritic Superalloys

Energy Technology Data Exchange (ETDEWEB)

Liaw, Peter

2014-12-31

A new class of ferritic superalloys containing B2-type zones inside parent L21-type precipitates in a disordered solid-solution matrix, also known as a hierarchical-precipitate strengthened ferritic alloy (HPSFA), has been developed for high-temperature structural applications in fossil-energy power plants. These alloys were designed by the addition of the Ti element into a previously-studied NiAl-strengthened ferritic alloy (denoted as FBB8 in this study). In the present research, systematic investigations, including advanced experimental techniques, first-principles calculations, and numerical simulations, have been integrated and conducted to characterize the complex microstructures and excellent creep resistance of HPSFAs. The experimental techniques include transmission-electron microscopy, scanningtransmission- electron microscopy, neutron diffraction, and atom-probe tomography, which provide detailed microstructural information of HPSFAs. Systematic tension/compression creep tests revealed that HPSFAs exhibit the superior creep resistance, compared with the FBB8 and conventional ferritic steels (i.e., the creep rates of HPSFAs are about 4 orders of magnitude slower than the FBB8 and conventional ferritic steels.) First-principles calculations include interfacial free energies, anti-phase boundary (APB) free energies, elastic constants, and impurity diffusivities in Fe. Combined with kinetic Monte- Carlo simulations of interdiffusion coefficients, and the integration of computational thermodynamics and kinetics, these calculations provide great understanding of thermodynamic and mechanical properties of HPSFAs. In addition to the systematic experimental approach and first-principles calculations, a series of numerical tools and algorithms, which assist in the optimization of creep properties of ferritic superalloys, are utilized and developed. These numerical simulation results are compared with the available experimental data and previous first

Computer Aided Design of Ni-Based Single Crystal Superalloy for Industrial Gas Turbine Blades

Science.gov (United States)

Wei, Xianping; Gong, Xiufang; Yang, Gongxian; Wang, Haiwei; Li, Haisong; Chen, Xueda; Gao, Zhenhuan; Xu, Yongfeng; Yang, Ming

The influence of molybdenum, tungsten and cobalt on stress-rupture properties of single crystal superalloy PWA1483 has been investigated using the simulated calculation of JMatPro software which ha s been widely used to develop single crystal superalloy, and the effect of alloying element on the stability of strengthening phase has been revealed by using the Thermo-Calc software. Those properties calculation results showed that the increasing of alloy content could facilitate the precipitation of TCP phases and increase the lattice misfit between γ and γ' phase, and the effect of molybdenum, tantalum was the strongest and that of cobalt was the weakest. Then the chemical composition was optimized, and the selected compositions showed excellent microstructure stability and stress-rupture properties by the confirmation of d-electrons concept and software calculation.

New concept of composite strengthening in Co-Re based alloys for high temperature applications in gas turbines

Energy Technology Data Exchange (ETDEWEB)

Mukherji, D.; Roesler, J.; Fricke, T.; Schmitz, F. [Technische Univ. Braunschweig (DE). Inst. fuer Werkstoffkunde (IfW); Piegert, S. [Siemens AG, Berlin (DE). Energy Sector (F PR GT EN)

2010-07-01

High temperature material development is mainly driven by gas turbine needs. Today, Ni-based superalloys are the dominant material class in the hot section of turbines. Material development will continue to push the maximum service temperature of Ni-superalloys upwards. However, this approach has a fundamental limit and can not be sustained indefinitely, as the Ni-superalloys are already used very close to their melting point. Within the frame work of a DFG Forschergruppe program (FOR 727) - ''Beyond Ni-base Superalloys'' - Co-Re based alloys are being developed as a new generation of high temperature materials that can be used at +100 C above single crystal Ni-superalloys. Along with other strengthening concepts, hardening by second phase is explored to develop a two phase composite alloy. With quaternary Co-Re-Cr-Ni alloys we demonstrate this development concept, where Co{sub 2}Re{sub 3}-type {sigma} phase is used in a novel way as the hardening phase. Thermodynamic calculation was used for designing model alloy compositions. (orig.)

Computational design and performance prediction of creep-resistant ferritic superalloys

Energy Technology Data Exchange (ETDEWEB)

Liaw, Peter K. [Univ. of Tennessee, Knoxville, TN (United States); Wang, Shao-Yu [Univ. of Tennessee, Knoxville, TN (United States); Dunand, David C. [Northwestern Univ., Evanston, IL (United States); Ghosh, Gautum [Northwestern Univ., Evanston, IL (United States); Song, Gian [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rawlings, Michael [Univ. of Tennessee, Knoxville, TN (United States); Baik, Sung Il [Northwestern Univ., Evanston, IL (United States)

2017-12-04

Ferritic superalloys containing the B2 phase with the parent L21 phase precipitates in a disordered solid-solution matrix, also known as a hierarchical-precipitate-strengthened ferritic alloy (HPSFA), had been developed for high-temperature structural applications in fossil-energy power plants. These alloys were designed by adding Ti into a previously-studied NiAl-strengthened ferritic alloy (denoted as FBB8 in this study). Following with the concept of HPSFAs, in the present research, a systematic investigation on adding other elements, such as Hf and Zr, and optimizing the Ti content within the alloy system, has been conducted, in order to further improve the creep resistance of the model alloys. Studies include advanced experimental techniques, first-principles calculations on thermodynamic and mechanical properties, and numerical simulations on precipitation hardening, have been integrated and conducted to characterize the complex microstructures and excellent creep resistance of alloys. The experimental techniques include transmission-electron microscopy (TEM), scanning-electron microscopy (SEM), neutron diffraction (ND), and atom-probe tomography (APT), which provide the detailed microstructural information of the model alloys. Systematic tension/compression creep tests have also been conducted in order to verify the creep resistance of the potential alloy compositions. The results show that when replacing Ti with Hf and Zr, it does not form the L21 phase. Instead, the hexagonal Laves phase forms and distributes majorly along the grain boundary, or large segregation within grains. Since the Laves phase does not form parent to the B2-phase precipitates, it cannot bring the strengthening effect of HPSFAs. As a result, the FBB8 + 2 wt. % Hf and FBB8 + 2 wt. % Zr alloys have similar mechanical properties to the original FBB8. The FBB8 + Ti series alloys had also been studied, from the creep tests and microstructural characterizations, the FBB8 + 3.5 wt.% Ti

The metallurgy of superalloys part 2

International Nuclear Information System (INIS)

Abdelazim, M.E.; Hammad, F.H.

1990-01-01

This is part II of the report titled 'the metallurgy of superalloys'. It deals with the effect of heat treatment and operating conditions (thermal exposure and environment) on the mechanical properties of superalloys. The heat treatment is important in the development of superalloys through that it controls type, amount, size shape and distribution of the precipitate and the grain size of the matrix. The thermal exposure leads to reduction in the amount of the primary carbides and to precipitation of secondary carbides. Also it leads to the agglomeration and coarsening of gamma or the transformation of gamma phase to phase. The environment may lead to the internal oxidation, carburization, decarburization or sulphidization of the superalloys which may result in the degradation of their mechanical properties. This part gives also an example of applications of superalloys in the field of nuclear reactors especially high temperature-gas cooled reactors. Joined with this part a table which contains the major superalloys including its chemical analysis, creep rupture strength and some of its applications. 1 tab

The metallurgy of superalloys part 1

International Nuclear Information System (INIS)

Abdelazim, M.E.; Hammad, F.H.

1990-01-01

This is part I of the report titled 'the metallurgy of superalloys'. In this part the structure, phases and systems of superalloys are reviewed. The role of alloying elements in the design of superalloys and the mechanical properties of superalloys are also reviewed. Superalloys are important in high temperature technology, especially above 700 degree c. They are 'super' mainly because their creep and stress rupture resistances are very high. Superalloys are based on an austenitic matrix including secondary phases, mainly gamma precipitates, inter and intragranular carbides mainly M 23 C 6 and M 6 C. They are classified into three systems, Ni-base, Fe-Ni base and Ce-base alloys. Different alloying elements mainly Cr, Mo, Al, Ti are added to increase the strength either by solid solution hardening (Cr, Mo, Al), precipitation hardening (A 1, Ti to produce gamma) or by dispersion hardening (Cr, Mo to form M 23 C 6 and M 6 C carbides) and to increase the oxidation resistance (Cr, Al). 3 tab., 2 fig

Characterisation of As-deformed microstructure of ODS NI-Base superalloy and ODS ferritic steel prior to directional recrystallisation

International Nuclear Information System (INIS)

Baloch, M.M.; Memon, S.A.

2007-01-01

The materials studied are unusual in the sense that they have been prepared from mechanically alloyed procedures, including compaction and hot extrusion. It was felt necessary to characterise the initial microstructure thoroughly prior to directional recrystallisation of the alloys. Following consolidation by hot extrusion, dispersion strengthened superalloys appear to display a very fine sub-micron grain size consisting of both dislocation free recrystallised material and un- recrystallised regions of high dislocation density. It is found that there is a very fine dislocation cell structure in the ODS (Oxide Dispersion Strengthened) Ferritic stainless Steel prior to recrystallisation treatment, which shows that alloy is in old-deformed condition after mechanical alloying, extrusion I hot-working. This is in contrast to the mechanically alloyed Nickel Base Superalloy, which have consistently been found to be in primary recrystallisation state following extrusion. In order to understand the recrystallisation behaviour of the two mechanically illoyed materials with commercial designations MA6000 and MA956, a measurement of the orientation relationship between adjacent grains in the as- deformed ODS alloys has also been carried out using Transmission Electron microscope. (author)

Designing Nanoscale Precipitates in Novel Cobalt-based Superalloys to Improve Creep Resistance and Operating Temperature

Energy Technology Data Exchange (ETDEWEB)

Dunand, David C. [Northwestern Univ., Evanston, IL (United States); Seidman, David N. [Northwestern Univ., Evanston, IL (United States); Wolverton, Christopher [Northwestern Univ., Evanston, IL (United States); Saal, James E. [Northwestern Univ., Evanston, IL (United States); Bocchini, Peter J. [Northwestern Univ., Evanston, IL (United States); Sauza, Daniel J. [Northwestern Univ., Evanston, IL (United States)

2014-10-01

High-temperature structural alloys for aerospace and energy applications have long been dominated by Ni-base superalloys, whose strength and creep resistance can be attributed to microstructures consisting of a large volume fraction of ordered (L1₂) γ'-precipitates embedded in a disordered’(f.c.c.) γ-matrix. These alloys exhibit excellent mechanical behavior and thermal stability, but after decades of incremental improvement are nearing the theoretical limit of their operating temperatures. Conventional Co-base superalloys are solid-solution or carbide strengthened; although they see industrial use, these alloys are restricted to lower-stress applications because the absence of an ordered intermetallic phase places an upper limit on their mechanical performance. In 2006, a γ+γ' microstructure with ordered precipitates analogous to (L1₂) Ni₃Al was first identified in the Co-Al-W ternary system, allowing, for the first time, the development of Co-base alloys with the potential to meet or even exceed the elevated-temperature performance of their Ni-base counterparts. The potential design space for these alloys is complex: the most advanced Ni-base superalloys may contain as many as 8-10 minor alloying additions, each with a specified purpose such as raising the γ' solvus temperature or improving creep strength. Our work has focused on assessing the effects of alloying additions on microstructure and mechanical behavior of γ'-strengthened Co-base alloys in an effort to lay the foundations for understanding this emerging alloy system. Investigation of the size, morphology, and composition of γ' and other relevant phases is investigated utilizing scanning electron microscopy (SEM) and 3-D picosecond ultraviolet local electrode atom probe tomography (APT). Microhardness, compressive yield stress at ambient and elevated temperatures, and compressive high-temperature creep measurements are employed to

Superior creep strength of a nickel-based superalloy produced by selective laser melting

Energy Technology Data Exchange (ETDEWEB)

Pröbstle, M., E-mail: martin.proebstle@fau.de [Department of Materials Science & Engineering Institute I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 5, D-91058 Erlangen (Germany); Neumeier, S.; Hopfenmüller, J.; Freund, L.P. [Department of Materials Science & Engineering Institute I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 5, D-91058 Erlangen (Germany); Niendorf, T. [Institut für Werkstofftechnik (Materials Engineering), Universität Kassel, Mönchebergstr. 3, D-34125 Kassel (Germany); Schwarze, D. [SLM Solutions GmbH, Roggenhorster Straße 9c, D-23556 Lübeck (Germany); Göken, M. [Department of Materials Science & Engineering Institute I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 5, D-91058 Erlangen (Germany)

2016-09-30

The creep properties of a polycrystalline nickel-based superalloy produced via selective laser melting were investigated in this study. All heat treatment conditions of the additively manufactured material show superior creep strength compared to conventional cast and wrought material. The process leads to a microstructure with fine subgrains. In comparison to conventional wrought material no Niobium rich δ phase is necessary to control the grain size and thus more Niobium is available for precipitation hardening and solid solution strengthening resulting in improved creep strength.

Thermo-Viscoplastic Behavior of Ni-Based Superalloy Haynes 282 and Its Application to Machining Simulation

Directory of Open Access Journals (Sweden)

Marcos Rodríguez-Millán

2017-12-01

Full Text Available Ni-based superalloys are extensively used in high-responsibility applications in components of aerospace engines and gas turbines with high temperature service lives. The wrought, γ’-strengthened superalloy Haynes 282 has been recently developed for applications similar to other common superalloys, such as Waspaloy or Inconel 718, with improved creep behavior, thermal stability, and fabrication ability. Despite the potential of Haynes 282, there are still important gaps in the knowledge of the mechanical behavior of this alloy. In fact, it was not possible to find information concerning the mechanical behavior of the alloy under impulsive loading. This paper focuses on the mechanical characterization of the Haynes 282 at strain rates ranging from 0.1 to 2800 s−1 and high temperatures ranging from 293 to 523 K using Hopkinson bar compression tests. The experimental results from the thermo-mechanical characterization allowed for calibration of the Johnson–Cook model widely used in modeling metallic alloy’s responses under dynamic loading. Moreover, the behavior of Haynes 282 was compared to that reported for Inconel 718, and the results were used to successfully model the orthogonal cutting of Haynes 282, being a typical case of dynamic loading requiring previous characterization of the alloy.

Expert systems for superalloy studies

Science.gov (United States)

Workman, Gary L.; Kaukler, William F.

1990-01-01

There are many areas in science and engineering which require knowledge of an extremely complex foundation of experimental results in order to design methodologies for developing new materials or products. Superalloys are an area which fit well into this discussion in the sense that they are complex combinations of elements which exhibit certain characteristics. Obviously the use of superalloys in high performance, high temperature systems such as the Space Shuttle Main Engine is of interest to NASA. The superalloy manufacturing process is complex and the implementation of an expert system within the design process requires some thought as to how and where it should be implemented. A major motivation is to develop a methodology to assist metallurgists in the design of superalloy materials using current expert systems technology. Hydrogen embrittlement is disasterous to rocket engines and the heuristics can be very complex. Attacking this problem as one module in the overall design process represents a significant step forward. In order to describe the objectives of the first phase implementation, the expert system was designated Hydrogen Environment Embrittlement Expert System (HEEES).

Soft Computing Methods in Design of Superalloys

Science.gov (United States)

Cios, K. J.; Berke, L.; Vary, A.; Sharma, S.

1996-01-01

Soft computing techniques of neural networks and genetic algorithms are used in the design of superalloys. The cyclic oxidation attack parameter K(sub a), generated from tests at NASA Lewis Research Center, is modelled as a function of the superalloy chemistry and test temperature using a neural network. This model is then used in conjunction with a genetic algorithm to obtain an optimized superalloy composition resulting in low K(sub a) values.

Introduction to superalloys

International Nuclear Information System (INIS)

Li-Chenggong

1995-01-01

Throughout history, humans have developed mechanical devices to satisfy their needs, Jet aircraft was thrust into public awareness with the 1937 flight of Hans Von Ohains turbine engine Heinkel in Germany and an independent development, the 1939 flight of Whittle's engine in England. Since that time, progress in jet propulsion and industrial gas turbines has been a growing engineering technology of immense importance. This opened a new era of engineering material called superalloy. Superalloy is an alloy developed for elevated temperature service usually based on group VIIA elements, where relatively severe mechanical stressing is encountered, and where high surface stability is frequently required. The title of the speech is T he Effect of a Changing Environment on the requirements of Engine Materials . In this speech, the author emphasized that may changes in the business environment have occurred in recent years, the aircraft engine business is rapidly changing from a military focus to a commercial one, speed to market will assume greater importance in the engine industry, and greater attention to customer value will be required to remain competitive etc. However the superalloys will continue to be developed in the future. (author) 14 figs

Looking for New Polycrystalline MC-Reinforced Cobalt-Based Superalloys Candidate to Applications at 1200°C

OpenAIRE

Patrice Berthod

2017-01-01

For applications for which temperatures higher than 1150°C can be encountered the currently best superalloys, the γ/γ′ single crystals, cannot be used under stress because of the disappearance of their reinforcing γ′ precipitates at such temperatures which are higher than their solvus. Cobalt-based alloys strengthened by refractory and highly stable carbides may represent an alternative solution. In this work the interest was focused on MC carbides of several types. Alloys were elaborated wit...

Cooling γ precipitation behavior and strengthening in powder metallurgy superalloy FGH4096

Institute of Scientific and Technical Information of China (English)

TIAN Gaofeng; JIA Chengchang; WEN Yin; LIU Guoquan; HU Benfu

2008-01-01

Two cooling schemes (continuous cooling and interrupted cooling tests) were applied to investigate the cooling γ precipitation behavior in powder metallurgy superalloy FGH4096.The effect of cooling rate on cooling γ precipitation and the development of γ precipitates during cooling process were involved in this study.The ultimate tensile strength (UTS) of the specimens in various cooling circumstances was tested.The experiential equations were obtained between the average sizes of secondary and tertiary γ precipitates,the strength,and cooling rate.The results show that they are inversely correlated with the cooling rate as well as the grain boundary changes from serrated to straight,the shape of secondary γ precipitates changes from irregular cuboidal to spherical,while the formed tertiary γ precipitates are always spherical.The interrupted cooling tests show that the average size of secondary γ precipitates increases as a linear function of interrupt temperature for a fixed cooling rate of 24℃/min.The strength first decreases and then increases against interrupt temperature,which is fundamentally caused by the multistage nucleation of γ precipitates during cooling process.

Modelling and simulation of superalloys. Book of abstracts

Energy Technology Data Exchange (ETDEWEB)

Rogal, Jutta; Hammerschmidt, Thomas; Drautz, Ralf (eds.)

2014-07-01

Superalloys are multi-component materials with complex microstructures that offer unique properties for high-temperature applications. The complexity of the superalloy materials makes it particularly challenging to obtain fundamental insight into their behaviour from the atomic structure to turbine blades. Recent advances in modelling and simulation of superalloys contribute to a better understanding and prediction of materials properties and therefore offer guidance for the development of new alloys. This workshop will give an overview of recent progress in modelling and simulation of materials for superalloys, with a focus on single crystal Ni-base and Co-base alloys. Topics will include electronic structure methods, atomistic simulations, microstructure modelling and modelling of microstructural evolution, solidification and process simulation as well as the modelling of phase stability and thermodynamics.

Innovative technologies for powder metallurgy-based disk superalloys: Progress and proposal

Science.gov (United States)

Chong-Lin, Jia; Chang-Chun, Ge; Qing-Zhi, Yan

2016-02-01

Powder metallurgy (PM) superalloys are an important class of high temperature structural materials, key to the rotating components of aero engines. In the purview of the present challenges associated with PM superalloys, two novel approaches namely, powder preparation and the innovative spray-forming technique (for making turbine disk) are proposed and studied. Subsequently, advanced technologies like electrode-induction-melting gas atomization (EIGA), and spark-plasma discharge spheroidization (SPDS) are introduced, for ceramic-free superalloy powders. Presently, new processing routes are sought after for preparing finer and cleaner raw powders for disk superalloys. The progress of research in spray-formed PM superalloys is first summarized in detail. The spray-formed superalloy disks specifically exhibit excellent mechanical properties. This paper reviews the recent progress in innovative technologies for PM superalloys, with an emphasis on new ideas and approaches, central to the innovation driving techniques like powder processing and spray forming. Project supported by the National Natural Science Foundation of China (Grant Nos. 50974016 and 50071014).

A high-throughput search for new ternary superalloys

Science.gov (United States)

Nyshadham, Chandramouli; Hansen, Jacob; Oses, Corey; Curtarolo, Stefano; Hart, Gus

In 2006 an unexpected new superalloy, Co3[Al,W], was discovered. This new alloy is cobalt-based, in contrast to conventional superalloys, which are nickel-based. Inspired by this new discovery, we performed first-principles calculations, searching through 2224 ternary metallic systems of the form A3[B0.5C0.5], where A = Ni/Co/Fe and [B, C] = all binary combinations of 40 different elements chosen from the periodic table. We found 175 new systems that are better than the Co3[Al, W] superalloy. 75 of these systems are brand new--they have never been reported in experimental literature. These 75 new potential superalloys are good candidates for further experiments. Our calculations are consistent with current experimental literature where data exists. Work supported under: ONR (MURI N00014-13-1-0635).

Recent trends in superalloys research for critical aero-engine components

Energy Technology Data Exchange (ETDEWEB)

Remy, Luc [Mine ParisTech, CNRS UMR 7633, 91 - Evry (France). Centre des Materiaux; Guedou, Jean-Yves [Snecma Safran Group, Moissy-Cramayel (France). Materials and Processes Dept.

2010-07-01

This paper is a brief survey of common research activity on superalloys for aero-engines between Snecma and Mines ParisTech Centre des Materiaux during recent years. First in disks applications, the development of new powder metallurgy superalloys is shown. Then grain boundary engineering is investigated in a wrought superalloy. Secondly, design oriented research on single crystals blades is shown: a damage model for low cycle fatigue is used for life prediction when cracks initiated at casting pores. The methodology developed for assessing coating life is illustrated for thermal barrier coating deposited on AMI single crystal superalloy. (orig.)

76 FR 8773 - Superalloy Degassed Chromium From Japan

Science.gov (United States)

2011-02-15

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-1090 (Review)] Superalloy Degassed Chromium From Japan AGENCY: United States International Trade Commission. ACTION: Termination of five-year... revocation of the antidumping duty order on superalloy degassed chromium from Japan would be likely to lead...

The Mechanical Properties of Candidate Superalloys for a Hybrid Turbine Disk

Science.gov (United States)

Gabb, Timothy P.; MacKay, Rebecca A.; Draper, Susan L.; Sudbrack, Chantal K.; Nathal, Michael V.

2013-01-01

The mechanical properties of several cast blade superalloys and one powder metallurgy disk superalloy were assessed for potential use in a dual alloy hybrid disk concept of joined dissimilar bore and web materials. Grain size was varied for each superalloy class. Tensile, creep, fatigue, and notch fatigue tests were performed at 704 to 815 degC. Typical microstructures and failure modes were determined. Preferred materials were then selected for future study as the bore and rim alloys in this hybrid disk concept. Powder metallurgy superalloy LSHR at 15 micron grain size and single crystal superalloy LDS-1101+Hf were selected for further study, and future work is recommended to develop the hybrid disk concept.

Effect of the microstructure on the creep behavior of PM Udimet 720 superalloy--experiments and modeling

International Nuclear Information System (INIS)

Dubiez-Le Goff, Sophie; Couturier, Raphaeel; Guetaz, Laure; Burlet, Helene

2004-01-01

Powder metallurgy processed Udimet 720 is a high creep strength nickel-based superalloy considered for high temperature turbine disks for nuclear gas cooled reactors working under 700 deg. C. Both fine-grained and coarse-grained microstructures have been obtained by applying respectively a subsolvus or a supersolvus solution treatments, followed by ageing treatments. In both microstructures, the distribution of the strengthening γ' precipitates has been characterized by transmission electron microscopy (TEM). The creep curves of the coarse-grained microstructure show the three usual creep stages. On the contrary, the creep curves of the fine-grained microstructure show a transition directly from primary to apparent tertiary creep without any obvious steady state. According to TEM analyses, Orowan loops surround Udimet 720 CR γ' and U720 HS γ' at high stress whereas U720 HS γ' are sheared at low stress. To describe the behavior of the superalloy Udimet 720, a specific creep model is developed on the basis of McLean and Dyson models including physical damage parameters

75 FR 67100 - Superalloy Degassed Chromium From Japan

Science.gov (United States)

2010-11-01

... Chromium From Japan AGENCY: United States International Trade Commission. ACTION: Institution of a five-year review concerning the antidumping duty order on superalloy degassed chromium from Japan. SUMMARY... order on superalloy degassed chromium from Japan would be likely to lead to continuation or recurrence...

Molecular dynamics study on the evolution of interfacial dislocation network and mechanical properties of Ni-based single crystal superalloys

Science.gov (United States)

Li, Nan-Lin; Wu, Wen-Ping; Nie, Kai

2018-05-01

The evolution of misfit dislocation network at γ /γ‧ phase interface and tensile mechanical properties of Ni-based single crystal superalloys at various temperatures and strain rates are studied by using molecular dynamics (MD) simulations. From the simulations, it is found that with the increase of loading, the dislocation network effectively inhibits dislocations emitted in the γ matrix cutting into the γ‧ phase and absorbs the matrix dislocations to strengthen itself which increases the stability of structure. Under the influence of the temperature, the initial mosaic structure of dislocation network gradually becomes irregular, and the initial misfit stress and the elastic modulus slowly decline as temperature increasing. On the other hand, with the increase of the strain rate, it almost has no effect on the elastic modulus and the way of evolution of dislocation network, but contributes to the increases of the yield stress and tensile strength. Moreover, tension-compression asymmetry of Ni-based single crystal superalloys is also presented based on MD simulations.

Fatigue studies of superalloys in Japan

International Nuclear Information System (INIS)

Kitagawa, Masaki

1985-01-01

In the past 15 years, several national projects were advanced to develop high temperature machinery, such as high temperature gas-cooled reactors, gas turbines and fusion reactors. Before, the studies on the strength of superalloys were rarely carried out, however, by the above research works, superalloys are in rapid progress. Because these machinery are subjected to temperature cycles and vibration stress, the fatigue failure is the main concern in the safety analysis of the components. The purpose of this paper is to summarize the present status of the fatigue research on the alloys for high temperature use in Japan. The superalloys used for gas turbine and HTGR components are listed, and the materials tested were mostly the alloys of nickel base, cobalt base or iron base. In the above national projects, the main purpose was to clarify the high temperature properties including fatigue properties, to develop the method of forecasting the life span and to develop better materials. As the topics about the fatigue research on superalloys, the development of the method for forecasting the life span, the effect of directional solidification, coating and HIP process on the fatigue strength of gas turbine materials, the effect of helium and aging on the fatigue strength of HTGR materials, the fatigue strength of weldment of HTGR materials and others are reported. (Kako, I.)

High temperature deformation mechanisms of L12-containing Co-based superalloys

Science.gov (United States)

Titus, Michael Shaw

Ni-based superalloys have been used as the structural material of choice for high temperature applications in gas turbine engines since the 1940s, but their operating temperature is becoming limited by their melting temperature (Tm =1300degrees C). Despite decades of research, no viable alternatives to Ni-based superalloys have been discovered and developed. However, in 2006, a ternary gamma' phase was discovered in the Co-Al-W system that enabled a new class of Co-based superalloys to be developed. These new Co-based superalloys possess a gamma-gamma' microstructure that is nearly identical to Ni-based superalloys, which enables these superalloys to achieve extraordinary high temperature mechanical properties. Furthermore, Co-based alloys possess the added benefit of exhibiting a melting temperature of at least 100degrees C higher than commercial Ni-based superalloys. Superalloys used as the structural materials in high pressure turbine blades must withstand large thermomechanical stresses imparted from the rotating disk and hot, corrosive gases present. These stresses induce time-dependent plastic deformation, which is commonly known as creep, and new superalloys must possess adequate creep resistance over a broad range of temperature in order to be used as the structural materials for high pressure turbine blades. For these reasons, this research focuses on quantifying high temperature creep properties of new gamma'-containing Co-based superalloys and identifying the high temperature creep deformation mechanisms. The high temperature creep properties of new Co- and CoNi-based alloys were found to be comparable to Ni-based superalloys with respect to minimum creep rates and creep-rupture lives at 900degrees C up to the solvus temperature of the gamma' phase. Co-based alloys exhibited a propensity for extended superlattice stacking fault formation in the gamma' precipitates resulting from dislocation shearing events. When Ni was added to the Co-based compositions

Fatigue properties of MA 6000E, a gamma-prime strengthened ODS alloy. [Oxide Dispersion Strengthened Ni-base alloy for gas turbine blade applications

Science.gov (United States)

Kim, Y. G.; Merrick, H. F.

1980-01-01

MA 6000E is a corrosion resistant, gamma-prime strengthened ODS alloy under development for advanced turbine blade applications. The high temperature, 1093 C, rupture strength is superior to conventional nickel-base alloys. This paper addresses the fatigue behavior of the alloy. Excellent properties are exhibited in low and high cycle fatigue and also thermal fatigue. This is attributed to a unique combination of microstructural features, i.e., a fine distribution of dispersed oxides and other nonmetallics, and the highly elongated grain structure which advantageously modify the deformation characteristics and crack initiation and propagation modes from that characteristic of conventional gamma-prime hardened superalloys.

NASA/ORNL/AFRL Project Work on EBM LSHR: Additive Manufacturing of High-Temperature Gamma-Prime Strengthened Ni-Based Superalloys

Science.gov (United States)

Sudbrack, Chantal K.; Kirka, Michael M.; Dehoff, Ryan R.; Carter, Robert W.; Semiatin, Sheldon L.; Gabb, Timothy P.

2016-01-01

Powder-bed fabrication of aerospace alloys may revolutionize production by eliminating the need for extensive machining and expensive tooling. Heated-bed electron-beam melting (EBM) offers advantages over non-heated laser additive manufacturing (AM) methods, including lower residual stress, reduced risk of contamination, slower cooling rates, and faster build times. NASA Glenn Research Center has joint project work with Oak Ridge National Lab and the Air Force Research Laboratory to explore the feasibility of fabricating advanced Ni-based gamma-prime superalloys with EBM AM.

Superalloy Lattice Block Developed for Use in Lightweight, High-Temperature Structures

Science.gov (United States)

Hebsur, Mohan G.; Whittenberger, J. Daniel; Krause, David L.

2003-01-01

Successful development of advanced gas turbine engines for aircraft will require lightweight, high-temperature components. Currently titanium-aluminum- (TiAl) based alloys are envisioned for such applications because of their lower density (4 g/cm3) in comparison to superalloys (8.5 g/cm3), which have been utilized for hot turbine engine parts for over 50 years. However, a recently developed concept (lattice block) by JAMCORP, Inc., of Willmington, Massachusetts, would allow lightweight, high-temperature structures to be directly fabricated from superalloys and, thus, take advantage of their well-known, characterized properties. In its simplest state, lattice block is composed of thin ligaments arranged in a three dimensional triangulated trusslike configuration that forms a structurally rigid panel. Because lattice block can be fabricated by casting, correctly sized hardware is produced with little or no machining; thus very low cost manufacturing is possible. Together, the NASA Glenn Research Center and JAMCORP have extended their lattice block methodology for lower melting materials, such as Al alloys, to demonstrate that investment casting of superalloy lattice block is possible. This effort required advances in lattice block pattern design and assembly, higher temperature mold materials and mold fabrication technology, and foundry practice suitable for superalloys (ref. 1). Lattice block panels have been cast from two different Ni-base superalloys: IN 718, which is the most commonly utilized superalloy and retains its strength up to 650 C; and MAR M247, which possesses excellent mechanical properties to at least 1100 C. In addition to the open-cell lattice block geometry, same-sized lattice block panels containing a thin (1-mm-thick) solid face on one side have also been cast from both superalloys. The elevated-temperature mechanical properties of the open cell and face-sheeted superalloy lattice block panels are currently being examined, and the

High temperature oxidation and corrosion behavior of Ni-base superalloy in He environment

International Nuclear Information System (INIS)

Lee, Gyoeng Geun; Park, Ji Yeon; Jung, Su jin

2010-11-01

Ni-base superalloy is considered as a IHX (Intermediate Heat Exchanger) material for VHTR (Very High Temperature Gas-Cooled Reactor). The helium environment in VHTR contains small amounts of impure gases, which cause oxidation, carburization, and decarburization. In this report, we conducted the literature survey about the high temperature behavior of Ni-base superalloys in air and He environments. The basic information of Ni-base superalloy and the basic metal-oxidation theory were briefly stated. The He effect on the corrosion of Ni-base superalloy was also summarized. This works would provide a brief suggestion for the next research topic for the application of Ni-base superalloy to VHTR

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...

Creep and rupture of an ODS alloy with high stress rupture ductility. [Oxide Dispersion Strengthened

Science.gov (United States)

Mcalarney, M. E.; Arsons, R. M.; Howson, T. E.; Tien, J. K.; Baranow, S.

1982-01-01

The creep and stress rupture properties of an oxide (Y2O3) dispersion strengthened nickel-base alloy, which also is strengthened by gamma-prime precipitates, was studied at 760 and 1093 C. At both temperatures, the alloy YDNiCrAl exhibits unusually high stress rupture ductility as measured by both elongation and reduction in area. Failure was transgranular, and different modes of failure were observed including crystallographic fracture at intermediate temperatures and tearing or necking almost to a chisel point at higher temperatures. While the rupture ductility was high, the creep strength of the alloy was low relative to conventional gamma prime strengthened superalloys in the intermediate temperature range and to ODS alloys in the higher temperature range. These findings are discussed with respect to the alloy composition; the strengthening oxide phases, which are inhomogeneously dispersed; the grain morphology, which is coarse and elongated and exhibits many included grains; and the second phase inclusion particles occurring at grain boundaries and in the matrix. The creep properties, in particular the high stress dependencies and high creep activation energies measured, are discussed with respect to the resisting stress model of creep in particle strengthened alloys.

Pervasive phosphorus limitation of tree species but not communities in tropical forests

Science.gov (United States)

Turner, Benjamin L.; Brenes-Arguedas, Tania; Condit, Richard

2018-03-01

Phosphorus availability is widely assumed to limit primary productivity in tropical forests, but support for this paradigm is equivocal. Although biogeochemical theory predicts that phosphorus limitation should be prevalent on old, strongly weathered soils, experimental manipulations have failed to detect a consistent response to phosphorus addition in species-rich lowland tropical forests. Here we show, by quantifying the growth of 541 tropical tree species across a steep natural phosphorus gradient in Panama, that phosphorus limitation is widespread at the level of individual species and strengthens markedly below a threshold of two parts per million exchangeable soil phosphate. However, this pervasive species-specific phosphorus limitation does not translate into a community-wide response, because some species grow rapidly on infertile soils despite extremely low phosphorus availability. These results redefine our understanding of nutrient limitation in diverse plant communities and have important implications for attempts to predict the response of tropical forests to environmental change.

Rafting in single crystal nickel-base superalloys – An overview

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

Page 1 ... aircraft engines as well as land-based power generation applications. Microstruc- ture and high temperature mechanical properties are the major factors controlling the performance of SX ... Single crystal (SX) superalloys are a group of nickel-base superalloys. They exhibit superior high temperatur mechanical ...

Erosion–corrosion behaviour of Ni-based superalloy Superni-75 in ...

Indian Academy of Sciences (India)

microscopy/energy-dispersive analysis (SEM/EDAX) and electron probe micro ... gas turbines and they have designated this alloy as superalloy Superni-75. ... The nickel-based superalloy Superni-75 (19·5Cr-3Fe-0·3Ti-0·1C- Balance Ni) was ...

Development of a Refractory High Entropy Superalloy (Postprint)

Science.gov (United States)

2016-03-17

hardened with HfC precipitates [2], Co-Re- or Co-Al-W-based alloys [3] or two-phase ( FCC + L12) refractory superalloys based on platinum group metals...Ni-based superalloys consisting of cuboids with the ordered L12 structure embedded in an FCC solid-solution matrix. Based on this microstructural...and 5). A comparison of the average atomic radii with the measured lattice parameters allows us to conclude that the disordered BCC phase forming

Effect of phosphorus on hot ductility of high purity iron

International Nuclear Information System (INIS)

Abiko, K.; Liu, C.M.; Ichikawa, M..; Suenaga, H.; Tanino, M.

1995-01-01

Tensile tests on high purity Fe-P alloys with 0, 0.05 and 0.1 mass%P were carried out at temperatures between 300 K and 1073 K to clarify the intrinsic effect of phosphorus on the mechanical properties of iron at elevated temperatures. Microstructures of as-quenched, interrupted and ruptured specimens were observed. Experimental results show that the addition of phosphorus causes a remarkable increase in proof stress of high purity iron at 300 K, but the increase in proof stress by phosphorus decreases with increasing test temperature. The strengthening effect of phosphorus reduces to zero at 1073 K. High purity iron and Fe-P alloys rupture at almost 100% reduction in area at the whole test temperatures. However, Fe-P alloys show much larger elongation at test temperatures above 773 K than high purity iron. The increased elongation of high purity iron by addition of phosphorus was shown to be related to the effect of phosphorus on dynamic recovery and recrystallization of iron as its intrinsic effect. (orig.)

Effects of cobalt on structure, microchemistry and properties of a wrought nickel-base superalloy

Science.gov (United States)

Jarrett, R. N.; Tien, J. K.

1982-01-01

The effect of cobalt on the basic mechanical properties and microstructure of wrought nickel-base superalloys has been investigated experimentally by systematically replacing cobalt by nickel in Udimet 700 (17 wt% Co) commonly used in gas turbine (jet engine) applications. It is shown that the room temperature tensile yield strength and tensile strength only slightly decrease in fine-grained (disk) alloys and are basically unaffected in coarse-grained (blading) alloys as cobalt is removed. Creep and stress rupture resistances at 760 C are found to be unaffected by cobalt level in the blading alloys and decrease sharply only when the cobalt level is reduced below 8 vol% in the disk alloys. The effect of cobalt is explained in terms of gamma prime strengthening kinetics.

Creep properties of heat-resistant superalloys for nuclear plants in helium

International Nuclear Information System (INIS)

Shimizu, Shigeki; Satoh, Keisuke; Honda, Yoshio; Matsuda, Shozo; Murase, Hirokazu

1979-01-01

Creep properties of candidate superalloys for VHTR components in a helium environment at both temperatures of 800 0 C and 900 0 C were compared with those of the same alloys in the atmospheric condition, and the superalloys were contrasted with each other from the viewpoint of high temperature structural design. At 800 0 C, no significant effect of a helium environment on creep properties of the superalloys is observed. At 900 0 C, however, creep strength of Inconel 617, Incoloy 800 and Incoloy 807 in the helium environment decrease more than in the atmospheric environment. In Hastelloy X and Inconel 625, there is no significant difference between creep strengths in helium and those in the atmospheric condition. Concerning So and St values in helium at 900 0 C, Inconel 617 and Hastelloy X are clearly superior to other superalloys. (author)

Development of Wrought Superalloy in China

Directory of Open Access Journals (Sweden)

DU Jinhui

2016-06-01

Full Text Available Wrought superalloy development in China was reviewed in recent ten years. The achievement of basic research and development of industrial manufacture technologies were systematically described from the aspects of new alloys, new technologies of hot deformation. New alloys include: new disc materials 718Plus, GH4720Li and GH4065 alloy, combustion chamber alloy GH3230, and GH4706 alloy for gas turbine engines. New technologies include: ERS-CDS new technology of easy segregation materials, multi upsetting-drawing for improving the microstructure uniformity of bars, slow cooling and multi-cycle thermomechanical treatment for increasing hot plasticity of hard-to-work alloys. Finally, the further development of wrought superalloys was prospected.

Integrated design of Nb-based superalloys: Ab initio calculations, computational thermodynamics and kinetics, and experimental results

International Nuclear Information System (INIS)

Ghosh, G.; Olson, G.B.

2007-01-01

An optimal integration of modern computational tools and efficient experimentation is presented for the accelerated design of Nb-based superalloys. Integrated within a systems engineering framework, we have used ab initio methods along with alloy theory tools to predict phase stability of solid solutions and intermetallics to accelerate assessment of thermodynamic and kinetic databases enabling comprehensive predictive design of multicomponent multiphase microstructures as dynamic systems. Such an approach is also applicable for the accelerated design and development of other high performance materials. Based on established principles underlying Ni-based superalloys, the central microstructural concept is a precipitation strengthened system in which coherent cubic aluminide phase(s) provide both creep strengthening and a source of Al for Al 2 O 3 passivation enabled by a Nb-based alloy matrix with required ductile-to-brittle transition temperature, atomic transport kinetics and oxygen solubility behaviors. Ultrasoft and PAW pseudopotentials, as implemented in VASP, are used to calculate total energy, density of states and bonding charge densities of aluminides with B2 and L2 1 structures relevant to this research. Characterization of prototype alloys by transmission and analytical electron microscopy demonstrates the precipitation of B2 or L2 1 aluminide in a (Nb) matrix. Employing Thermo-Calc and DICTRA software systems, thermodynamic and kinetic databases are developed for substitutional alloying elements and interstitial oxygen to enhance the diffusivity ratio of Al to O for promotion of Al 2 O 3 passivation. However, the oxidation study of a Nb-Hf-Al alloy, with enhanced solubility of Al in (Nb) than in binary Nb-Al alloys, at 1300 deg. C shows the presence of a mixed oxide layer of NbAlO 4 and HfO 2 exhibiting parabolic growth

Effect of phosphorus on biodiesel production from Scenedesmus obliquus under nitrogen-deficiency stress.

Science.gov (United States)

Chu, Fei-Fei; Chu, Pei-Na; Shen, Xiao-Fei; Lam, Paul K S; Zeng, Raymond J

2014-01-01

In order to study the effect of phosphorus on biodiesel production from Scenedesmus obliquus especially under nitrogen deficiency conditions, six types of media with combinations of nitrogen repletion/depletion and phosphorus repletion/limitation/depletion were investigated in this study. It was found that nitrogen starvation compared to nitrogen repletion enhanced biodiesel productivity. Moreover, biodiesel productivity was further strengthened by varying the supply level of phosphorus from depletion, limitation, through to repletion. The maximum FAMEs productivity of 24.2 mg/L/day was obtained in nitrogen depletion with phosphorus repletion, which was two times higher than that in nutrient complete medium. More phosphorus was accumulated in cells under the nitrogen starvation with sufficient phosphorus condition, but no polyphosphate was formed. This study indicated that nitrogen starvation plus sufficient P supply might be the real "lipid trigger". Furthermore, results of the current study suggest a potential application for utilizing microalgae to combine phosphorus removal from wastewater with biodiesel production. Copyright © 2013 Elsevier Ltd. All rights reserved.

Numerical multi-criteria optimization methods for alloy design. Development of new high strength nickel-based superalloys and experimental validation

Energy Technology Data Exchange (ETDEWEB)

Rettig, Ralf; Mueller, Alexander; Ritter, Nils C.; Singer, Robert F. [Institute of Science and Technology of Metals, Department of Materials Science and Engineering, University of Erlangen (Germany)

2016-07-01

A new approach for the design of optimum balanced metallic alloys is presented. It is based on a mathematical multi-criteria optimization method which uses different property models to predict the alloy behavior in dependency of composition. These property models are mostly based on computational thermodynamics (CALPHAD-method). The full composition range of the alloying elements can be considered using these models. In alloy design usually several contradicting goals have to be fulfilled. This is handled by the calculation of so-called Pareto-fronts. The aim of our approach is to guide the experimental research towards new alloy compositions that have a high probability of having very good properties. Consequently the number of required test alloys can be massively reduced. The approach will be demonstrated for the computer-aided design of a new Re-free superalloy with nearly identical creep strength as that of Re-containing superalloys. Our starting point for the design was to maintain the good properties of the gamma prime-phase in well-known alloys like CMSX-4 and to maximize the solid solution strengthening of W and Mo. The presented experimental measurements proof the excellent properties.

Fatigue of superalloys and intermetallics

International Nuclear Information System (INIS)

Stoloff, N.S.

1993-01-01

The fatigue behavior of intermetallic alloys and their composites is contrasted to that of nickel-base superalloys. The roles of microstructure and slip planarity are emphasized. Obstacles to use of intermetallics under cyclic loading conditions are described and future research directions are suggested

Barrier Coatings for Refractory Metals and Superalloys

Energy Technology Data Exchange (ETDEWEB)

SM Sabol; BT Randall; JD Edington; CJ Larkin; BJ Close

2006-02-23

In the closed working fluid loop of the proposed Prometheus space nuclear power plant (SNPP), there is the potential for reaction of core and plant structural materials with gas phase impurities and gas phase transport of interstitial elements between superalloy and refractory metal alloy components during service. Primary concerns are surface oxidation, interstitial embrittlement of refractory metals and decarburization of superalloys. In parallel with kinetic investigations, this letter evaluates the ability of potential coatings to prevent or impede communication between reactor and plant components. Key coating requirements are identified and current technology coating materials are reviewed relative to these requirements. Candidate coatings are identified for future evaluation based on current knowledge of design parameters and anticipated environment. Coatings were identified for superalloys and refractory metals to provide diffusion barriers to interstitial transport and act as reactive barriers to potential oxidation. Due to their high stability at low oxygen potential, alumina formers are most promising for oxidation protection given the anticipated coolant gas chemistry. A sublayer of iridium is recommended to provide inherent diffusion resistance to interstitials. Based on specific base metal selection, a thin film substrate--coating interdiffusion barrier layer may be necessary to meet mission life.

Barrier Coatings for Refractory Metals and Superalloys

International Nuclear Information System (INIS)

SM Sabol; BT Randall; JD Edington; CJ Larkin; BJ Close

2006-01-01

In the closed working fluid loop of the proposed Prometheus space nuclear power plant (SNPP), there is the potential for reaction of core and plant structural materials with gas phase impurities and gas phase transport of interstitial elements between superalloy and refractory metal alloy components during service. Primary concerns are surface oxidation, interstitial embrittlement of refractory metals and decarburization of superalloys. In parallel with kinetic investigations, this letter evaluates the ability of potential coatings to prevent or impede communication between reactor and plant components. Key coating requirements are identified and current technology coating materials are reviewed relative to these requirements. Candidate coatings are identified for future evaluation based on current knowledge of design parameters and anticipated environment. Coatings were identified for superalloys and refractory metals to provide diffusion barriers to interstitial transport and act as reactive barriers to potential oxidation. Due to their high stability at low oxygen potential, alumina formers are most promising for oxidation protection given the anticipated coolant gas chemistry. A sublayer of iridium is recommended to provide inherent diffusion resistance to interstitials. Based on specific base metal selection, a thin film substrate--coating interdiffusion barrier layer may be necessary to meet mission life

Zinc-induced embrittlement in nickel-base superalloys by simulation and experiment

Science.gov (United States)

Otis, Richard; Waje, Mahesh; Lindwall, Greta; Jefferson, Tiffany; Lange, Jeremy; Liu, Zi-Kui

2017-09-01

The high cost of Re has driven interest in processes for recovering Re from scrap superalloy parts. In this work thermodynamic modelling is used to study Zn-induced embrittlement of a superalloy and to direct experiments. Treating superalloy powder with Zn vapour reduces the average particle size after milling from approximately ?m to 0.5-10 ?m, vs. ?m for untreated powder. Simulations predict the required treatment time to increase with temperature. Agreement between predictions and experiments suggests that an embrittling liquid forms in less than an hour of Zn vapour treatment between 950-1000 ?C and partial pressures of Zn between 14-34 kPa (2-5 psi).

A Review on Inertia and Linear Friction Welding of Ni-Based Superalloys

Science.gov (United States)

Chamanfar, Ahmad; Jahazi, Mohammad; Cormier, Jonathan

2015-04-01

Inertia and linear friction welding are being increasingly used for near-net-shape manufacturing of high-value materials in aerospace and power generation gas turbines because of providing a better quality joint and offering many advantages over conventional fusion welding and mechanical joining techniques. In this paper, the published works up-to-date on inertia and linear friction welding of Ni-based superalloys are reviewed with the objective to make clarifications on discrepancies and uncertainties reported in literature regarding issues related to these two friction welding processes as well as microstructure, texture, and mechanical properties of the Ni-based superalloy weldments. Initially, the chemical composition and microstructure of Ni-based superalloys that contribute to the quality of the joint are reviewed briefly. Then, problems related to fusion welding of these alloys are addressed with due consideration of inertia and linear friction welding as alternative techniques. The fundamentals of inertia and linear friction welding processes are analyzed next with emphasis on the bonding mechanisms and evolution of temperature and strain rate across the weld interface. Microstructural features, texture development, residual stresses, and mechanical properties of similar and dissimilar polycrystalline and single crystal Ni-based superalloy weldments are discussed next. Then, application of inertia and linear friction welding for joining Ni-based superalloys and related advantages over fusion welding, mechanical joining, and machining are explained briefly. Finally, present scientific and technological challenges facing inertia and linear friction welding of Ni-based superalloys including those related to modeling of these processes are addressed.

Superalloy applications in the fast breeder reactor

International Nuclear Information System (INIS)

Powell, R.W.

1976-01-01

The economics of the LMFBR are dependent on the breeding of new fuel in the reactor core and this can be improved by the use of advanced alloys as core structural components. The environment of the core makes superalloys a natural choice for these components, but phenomena related directly to neutron irradiation necessitate extensive testing. Consequently, commercially-available superalloys, together with a number of developmental alloys are being tested in existing LMFBR's and by simulation techniques to determine the best alloy for use in the LMFBR core. It presently appears that such materials will indeed be capable of the performance required, and will greatly facilitate the commercial realization of the fast breeder reactor

Predicting the morphologies of {\\gamma}' precipitates in cobalt-based superalloys

OpenAIRE

Jokisaari, Andrea M.; Naghavi, Shahab S.; Wolverton, Chris; Voorhees, Peter W.; Heinonen, Olle G.

2017-01-01

Cobalt-based alloys with {\\gamma}/{\\gamma}' microstructures have the potential to become the next generation of superalloys, but alloy compositions and processing steps must be optimized to improve coarsening, creep, and rafting behavior. While these behaviors are different than in nickel-based superalloys, alloy development can be accelerated by understanding the thermodynamic factors influencing microstructure evolution. In this work, we develop a phase field model informed by first-princip...

A New Superalloy Enabling Heavy Duty Gas Turbine Wheels for Improved Combined Cycle Efficiency

Energy Technology Data Exchange (ETDEWEB)

Detor, Andrew [General Electric Company, Niskayuna, NY (United States). GE Global Research; DiDomizio, Richard [General Electric Company, Niskayuna, NY (United States). GE Global Research; McAllister, Don [The Ohio State Univ., Columbus, OH (United States); Sampson, Erica [General Electric Company, Niskayuna, NY (United States). GE Global Research; Shi, Rongpei [The Ohio State Univ., Columbus, OH (United States); Zhou, Ning [General Electric Company, Niskayuna, NY (United States). GE Global Research

2017-01-03

The drive to increase combined cycle turbine efficiency from 62% to 65% for the next-generation advanced cycle requires a new heavy duty gas turbine wheel material capable of operating at 1200°F and above. Current wheel materials are limited by the stability of their major strengthening phase (gamma double prime), which coarsens at temperatures approaching 1200°F, resulting in a substantial reduction in strength. More advanced gamma prime superalloys, such as those used in jet engine turbine disks, are also not suitable due to size constraints; the gamma prime phase overages during the slow cooling rates inherent in processing thick-section turbine wheels. The current program addresses this need by screening two new alloy design concepts. The first concept exploits a gamma prime/gamma double prime coprecipitation reaction. Through manipulation of alloy chemistry, coprecipitation is controlled such that gamma double prime is used only to slow the growth of gamma prime during slow cooling, preventing over-aging, and allowing for subsequent heat treatment to maximize strength. In parallel, phase field modeling provides fundamental understanding of the coprecipitation reaction. The second concept uses oxide dispersion strengthening to improve on two existing alloys that exhibit excellent hold time fatigue crack growth resistance, but have insufficient strength to be considered for gas turbine wheels. Mechanical milling forces the dissolution of starting oxide powders into a metal matrix allowing for solid state precipitation of new, nanometer scale oxides that are effective at dispersion strengthening.

High temperature oxidation characteristics of developed Ni-Cr-W superalloys in air

International Nuclear Information System (INIS)

Suzuki, Tomio; Shindo, Masami

1996-11-01

For expanding utilization of the Ni-Cr-W superalloy, which has been developed as one of new high temperature structural materials used in the advanced High Temperature Gas-cooled Reactors (HTGRs), in various engineering fields including the structural material for heat utilization system, the oxidation behavior of this alloy in air as one of high oxidizing environments becomes one of key factors. The oxidation tests for the industrial scale heat of Ni-Cr-W superalloy with the optimized chemical composition and five kinds of experimental Ni-Cr-W alloys with different Cr/W ratio were carried out at high temperatures in the air compared with Hastelloy XR. The conclusions were obtained as follows. (1) The oxidation resistance of the industrial scale heat of Ni-Cr-W superalloy with the optimized chemical composition was superior to that of Hastelloy XR. (2) The most excellent oxidation resistance was obtained in an alloy with 19% Cr of the industrial scale heat of Ni-Cr-W superalloy. (author)

Thermomechanical fatigue in single crystal superalloys

Directory of Open Access Journals (Sweden)

Moverare Johan J.

2014-01-01

Full Text Available Thermomechanical fatigue (TMF is a mechanism of deformation which is growing in importance due to the efficiency of modern cooling systems and the manner in which turbines and associated turbomachinery are now being operated. Unfortunately, at the present time, relatively little research has been carried out particularly on TMF of single crystal (SX superalloys, probably because the testing is significantly more challenging than the more standard creep and low cycle fatigue (LCF cases; the scarcity and relative expense of the material are additional factors. In this paper, the authors summarise their experiences on the TMF testing of SX superalloys, built up over several years. Emphasis is placed upon describing: (i the nature of the testing method, the challenges involved in ensuring that an given testing methodology is representative of engine conditions (ii the behaviour of a typical Re-containing second generation alloy such as CMSX-4, and its differing performance in out-of-phase/in-phase loading and crystallographic orientation and (iii the differences in behaviour displayed by the Re-containing alloys and new Re-free variants such as STAL15. It is demonstrated that the Re-containing superalloys are prone to different degradation mechanisms involving for example microtwinning, TCP precipitation and recrystallisation. The performance of STAL15 is not too inferior to alloys such as CMSX-4, suggesting that creep resistance itself does not correlate strongly with resistance to TMF. The implications for alloy design efforts are discussed.

Noburnium: Systems design of niobium superalloys

Science.gov (United States)

Misra, Abhijeet

2005-11-01

A systems-based approach, integrating quantum mechanical calculations with efficient experimentation, was employed to design niobium-based superalloys. The microstructural concept of gamma-gamma' nickel-based superalloys was adopted, where, the coherent gamma ' aluminides act both as the strengthening phase and a source of aluminum for Al2O3 passivation. Building on previous research, the selected bcc-type ordered aluminide was L2 1 structured Pd2HfAl phase. Comprehensive phase relations were measured on Nb-Pd-Hf-Al prototype alloys, and key tie-tetrahedra were identified. Aluminide precipitation in a bcc matrix was demonstrated in designed Nb+Pd2HfAl alloys. Thermodynamic databases were developed by integrating first-principles calculations with measured phase relations. Atomic volume models were developed for the bcc matrix and the Pd2HfAl phase and matrix elements which would reduce lattice misfit were identified. An experimental 2-phase alloy demonstrated a misfit of 3%. A modified Wagner's model was used to predict the required transient properties to form external Al2O3. The principal oxidation design goal was to decrease the oxygen permeability ( NSOx DO ) divided by the aluminum diffusivity (DAl) by 5 orders of magnitude. A multicomponent mobility database was developed to predict the diffusivities. Guided by first-principles calculations the effect of alloying elements on the oxygen diffusivity in Nb was measured, and the mobility database was experimentally validated. Based on the mobility database, it was found that increasing Al solubility in the bcc matrix greatly increased Al diffusivity. Alloying elements were identified that would increase Al solubility in the bcc matrix. Prototype alloys were prepared and the best oxidation performance was exhibited by a bcc+Nb2Al Nb-Hf-Al alloy, which exhibited parabolic oxidation behavior at 1300°C. The alloy was shown to have achieved the required 5 orders of magnitude reduction in the design parameter. The

A new method in prediction of TCP phases formation in superalloys

International Nuclear Information System (INIS)

Mousavi Anijdan, S.H.; Bahrami, A.

2005-01-01

The purpose of this investigation is to develop a model for prediction of topologically closed-packed (TCP) phases formation in superalloys. In this study, artificial neural networks (ANN), using several different network architectures, were used to investigate the complex relationships between TCP phases and chemical composition of superalloys. In order to develop an optimum ANN structure, more than 200 experimental data were used to train and test the neural network. The results of this investigation shows that a multilayer perceptron (MLP) form of the neural networks with one hidden layer and 10 nodes in the hidden layer has the lowest mean absolute error (MAE) and can be accurately used to predict the electron-hole number (N v ) and TCP phases formation in superalloys

A Comparison of the Plastic Flow Response of a Powder Metallurgy Nickel Base Superalloy (Postprint)

Science.gov (United States)

2017-04-01

AFRL-RX-WP-JA-2017-0225 A COMPARISON OF THE PLASTIC-FLOW RESPONSE OF A POWDER- METALLURGY NICKEL-BASE SUPERALLOY (POSTPRINT) S.L...COMPARISON OF THE PLASTIC-FLOW RESPONSE OF A POWDER- METALLURGY NICKEL-BASE SUPERALLOY (POSTPRINT) 5a. CONTRACT NUMBER IN-HOUSE 5b. GRANT...behavior at hot-working temperatures and strain rates of the powder- metallurgy superalloy LSHR was determined under nominally-isothermal and transient

σ and η Phase formation in advanced polycrystalline Ni-base superalloys

Energy Technology Data Exchange (ETDEWEB)

Antonov, Stoichko, E-mail: santonov@hawk.iit.edu [Illinois Institute of Technology, 10 W. 32nd Street, Chicago, IL 60616 (United States); Huo, Jiajie; Feng, Qiang [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Isheim, Dieter; Seidman, David N. [Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL 60208 (United States); Northwestern University Center for Atom Probe Tomography (NUCAPT), 2220 Campus Drive, Evanston, IL 60208 (United States); Helmink, Randolph C.; Sun, Eugene [Rolls-Royce Corporation, 450 S. Meridian Street, Indianapolis, IN 46225 (United States); Tin, Sammy [Illinois Institute of Technology, 10 W. 32nd Street, Chicago, IL 60616 (United States)

2017-02-27

In polycrystalline Ni-base superalloys, grain boundary precipitation of secondary phases can be significant due to the effects they pose on the mechanical properties. As new alloying concepts for polycrystalline Ni-base superalloys are being developed to extend their temperature capability, the effect of increasing levels of Nb alloying additions on long term phase stability and the formation of topologically close packed (TCP) phases needs to be studied. Elevated levels of Nb can result in increased matrix supersaturation and promote the precipitation of secondary phases. Long term thermal exposures on two experimental powder processed Ni-base superalloys containing various levels of Nb were completed to assess the stability and precipitation of TCP phases. It was found that additions of Nb promoted the precipitation of η-Ni{sub 6}AlNb along the grain boundaries in powder processed, polycrystalline Ni-base superalloys, while reduced Nb levels favored the precipitation of blocky Cr and Mo – rich σ phase precipitates along the grain boundary. Evaluation of the thermodynamic stability of these two phases in both alloys using Thermo-calc showed that while σ phase predictions are fairly accurate, predictions of the η phase are limited.

Precipitation in Powder Metallurgy, Nickel Base Superalloys: Review of Modeling Approach and Formulation of Engineering (Postprint)

Science.gov (United States)

2016-12-01

AFRL-RX-WP-JA-2016-0333 PRECIPITATION IN POWDER- METALLURGY , NICKEL-BASE SUPERALLOYS: REVIEW OF MODELING APPROACH AND FORMULATION OF...PRECIPITATION IN POWDER- METALLURGY , NICKEL- BASE SUPERALLOYS: REVIEW OF MODELING APPROACH AND FORMULATION OF ENGINEERING (POSTPRINT) 5a...and kinetic parameters required for the modeling of γ′ precipitation in powder- metallurgy (PM), nickel-base superalloys are summarized. These

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

Welding and Weldability of Directionally Solidified Single Crystal Nickel-Base Superalloys

Energy Technology Data Exchange (ETDEWEB)

Vitek, J M; David, S A; Reed, R W; Burke, M A; Fitzgerald, T J

1997-09-01

Nickel-base superalloys are used extensively in high-temperature service applications, and in particular, in components of turbine engines. To improve high-temperature creep properties, these alloys are often used in the directionally-solidified or single-crystal form. The objective of this CRADA project was to investigate the weldability of both experimental and commercial nickel-base superalloys in polycrystalline, directionally-solidified, and single-crystal forms.

Effect of Notches on Creep-Fatigue Behavior of a P/M Nickel-Based Superalloy

Science.gov (United States)

Telesman, Jack; Gabb, Timothy P.; Ghosn, Louis J.; Gayda, John, Jr.

2015-01-01

A study was performed to determine and model the effect of high temperature dwells on notched low cycle fatigue (NLCF) and notch stress rupture behavior of a fine grain LSHR powder metallurgy (PM) nickel-based superalloy. It was shown that a 90 second dwell applied at the minimum stress (min dwell) was considerably more detrimental to the NLCF lives than similar dwell applied at the maximum stress (max dwell). The short min dwell NLCF lives were shown to be caused by growth of small oxide blisters which caused preferential cracking when coupled with high concentrated notch root stresses. The cyclic max dwell notch tests failed mostly by a creep accumulation, not by fatigue, with the crack origin shifting internally to a substantial distance away from the notch root. The classical von Mises plastic flow model was unable to match the experimental results while the hydrostatic stress profile generated using the Drucker-Prager plasticity flow model was consistent with the experimental findings. The max dwell NLCF and notch stress rupture tests exhibited substantial creep notch strengthening. The triaxial Bridgman effective stress parameter was able to account for the notch strengthening by collapsing the notched and uniform gage geometry test data into a singular grouping.

Cobalt-free nickel-base superalloys

International Nuclear Information System (INIS)

Koizumi, Yutaka; Yamazaki, Michio; Harada, Hiroshi

1979-01-01

Cobalt-free nickel-base cast superalloys have been developed. Cobalt is considered to be a beneficial element to strengthen the alloys but should be eliminated in alloys to be used for direct cycle helium turbine driven by helium gas from HTGR (high temp. gas reactor). The elimination of cobalt is required to avoid the formation of radioactive 60 Co from the debris or scales of the alloys. Cobalt-free alloys are also desirable from another viewpoint, i.e. recently the shortage of the element has become a serious problem in industry. Cobalt-free Mar-M200 type alloys modified by the additions of 0.15 - 0.2 wt% B and 1 - 1.5 wt% Hf were found to have a creep rupture strength superior or comparable to that of the original Mar-M200 alloy bearing cobalt. The ductility in tensile test at 800 0 C, as cast or after prolonged heating at 900 0 C (the tensile test was done without removing the surface layer affected by the heating), was also improved by the additions of 0.15 - 0.2% B and 1 - 1.5% Hf. The morphology of grain boundaries became intricated by the additions of 0.15 - 0.2% B and 1 - 1.5% Hf, to such a degree that one can hardly distinguish grain boundaries by microscopes. The change in the grain boundary morphology was considered, as suggested previously by one of the authors (M.Y.), to be the reason for the improvements in the creep rupture strength and tensile ductility. (author)

Modeling Long-term Creep Performance for Welded Nickel-base Superalloy Structures for Power Generation Systems

Energy Technology Data Exchange (ETDEWEB)

Shen, Chen

2015-01-01

We report here a constitutive model for predicting long-term creep strain evolution in’ strengthened Ni-base superalloys. Dislocation climb-bypassing’, typical in intermediate’ volume fraction (~20%) alloys, is considered as the primary deformation mechanism. Dislocation shearing’ to anti-phase boundary (APB) faults and diffusional creep are also considered for high-stress and high-temperature low-stress conditions, respectively. Additional damage mechanism is taken into account for rapid increase in tertiary creep strain. The model has been applied to Alloy 282, and calibrated in a temperature range of 1375-1450°F, and stress range of 15-45ksi. The model parameters and a MATLAB code are provided. This report is prepared by Monica Soare and Chen Shen at GE Global Research. Technical discussions with Dr. Vito Cedro are greatly appreciated. This work was supported by DOE program DE-FE0005859

Influence of Short-time Oxidation on Corrosion Properties of Directionally Solidified Superalloys with Different Orientations

Directory of Open Access Journals (Sweden)

MA Luo-ning

2016-07-01

Full Text Available In order to investigate the corrosion performance on intersecting and longitudinal surfaces of unoxidized and oxidized directionally solidified superalloys, Ni-base directionally solidified superalloy DZ125 and Co-base directionally solidified superalloy DZ40M were selected. Oxidation behavior on both alloys with different orientations was investigated at 1050℃ at different times, simulating the oxidation process of vanes or blades in service; subsequent electrochemical performance in 3.5%NaCl aqueous solution was studied on two orientations of unoxidized and oxidized alloys, simulating the corrosion process of superalloy during downtime. The results show that grain boundaries and sub-boundaries of directionally solidified superalloys are susceptible to corrosion and thus longitudinal surface with lower area fraction of grain boundaries has higher corrosion resistance. Compared to intersecting surface of alloys, the structure of grain boundaries of longitudinal surface is less conducive to diffusion and thus the oxidation rate on longitudinal surface is lower. Formation of oxide layers on alloys after short-time oxidation provides protective effect and enhances the corrosion resistance.

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.

Chemical driving force for rafting in superalloys

CSIR Research Space (South Africa)

Nabarro, FRN

1997-08-15

Full Text Available The author provides a brief overview of the chemical driving forces for rafting in superalloys. Until recently, all theories of the driving force for rafting have considered the compositions of the two phases to be fixed, although accepting...

Grinding of Inconel 713 superalloy for gas turbines

Czech Academy of Sciences Publication Activity Database

Čapek, J.; Kyncl, J.; Kolařík, K.; Beránek, L.; Pitrmuc, Z.; Medřický, Jan; Pala, Z.

2016-01-01

Roč. 16, č. 1 (2016), s. 14-15 ISSN 1213-2489 Institutional support: RVO:61389021 Keywords : Casting defects * Gas turbine * Grinding * Nickel superalloy * Residual stresses Subject RIV: JJ - Other Materials

Freckle Defect Formation near the Casting Interfaces of Directionally Solidified Superalloys.

Science.gov (United States)

Hong, Jianping; Ma, Dexin; Wang, Jun; Wang, Fu; Sun, Baode; Dong, Anping; Li, Fei; Bührig-Polaczek, Andreas

2016-11-16

Freckle defects usually appear on the surface of castings and industrial ingots during the directional solidification process and most of them are located near the interface between the shell mold and superalloys. Ceramic cores create more interfaces in the directionally solidified (DS) and single crystal (SX) hollow turbine blades. In order to investigate the location of freckle occurrence in superalloys, superalloy CM247 LC was directionally solidified in an industrial-sized Bridgman furnace. Instead of ceramic cores, Alumina tubes were used inside of the casting specimens. It was found that freckles occur not only on the casting external surfaces, but also appear near the internal interfaces between the ceramic core and superalloys. Meanwhile, the size, initial position, and area of freckle were investigated in various diameters of the specimens. The initial position of the freckle chain reduces when the diameter of the rods increase. Freckle area follows a linear relationship in various diameters and the average freckle fraction is 1.1% of cross sectional area of casting specimens. The flow of liquid metal near the interfaces was stronger than that in the interdendritic region in the mushy zone, and explained why freckle tends to occur on the outer or inner surfaces of castings. This new phenomenon suggests that freckles are more likely to occur on the outer or inner surfaces of the hollow turbine blades.

Freckle Defect Formation near the Casting Interfaces of Directionally Solidified Superalloys

Directory of Open Access Journals (Sweden)

Jianping Hong

2016-11-01

Full Text Available Freckle defects usually appear on the surface of castings and industrial ingots during the directional solidification process and most of them are located near the interface between the shell mold and superalloys. Ceramic cores create more interfaces in the directionally solidified (DS and single crystal (SX hollow turbine blades. In order to investigate the location of freckle occurrence in superalloys, superalloy CM247 LC was directionally solidified in an industrial-sized Bridgman furnace. Instead of ceramic cores, Alumina tubes were used inside of the casting specimens. It was found that freckles occur not only on the casting external surfaces, but also appear near the internal interfaces between the ceramic core and superalloys. Meanwhile, the size, initial position, and area of freckle were investigated in various diameters of the specimens. The initial position of the freckle chain reduces when the diameter of the rods increase. Freckle area follows a linear relationship in various diameters and the average freckle fraction is 1.1% of cross sectional area of casting specimens. The flow of liquid metal near the interfaces was stronger than that in the interdendritic region in the mushy zone, and explained why freckle tends to occur on the outer or inner surfaces of castings. This new phenomenon suggests that freckles are more likely to occur on the outer or inner surfaces of the hollow turbine blades.

Design of high entropy alloys based on the experience from commercial superalloys

Science.gov (United States)

Wang, Z.; Huang, Y.; Wang, J.; Liu, C. T.

2015-01-01

High entropy alloys (HEAs) have been drawing increasing attention recently and gratifying results have been obtained. However, the existing metallurgic rules of HEAs could not provide specific information of selecting candidate alloys for structural applications. Our brief survey reveals that many commercial superalloys have medium and even to high configurational entropies. The experience of commercial superalloys provides a clue for helping us in the development of HEAs for structural applications.

The Effect of Forging Variables on the Supersolvus Heat-Treatment Response of Powder-Metallurgy Nickel-Base Superalloys

Science.gov (United States)

2014-12-01

AFRL-RX-WP-JA-2015-0160 THE EFFECT OF FORGING VARIABLES ON THE SUPERSOLVUS HEAT-TREATMENT RESPONSE OF POWDER - METALLURGY NICKEL-BASE SUPERALLOYS... POWDER - METALLURGY NICKEL- BASE SUPERALLOYS (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6. AUTHOR...treatment (SSHT) of two powder - metallurgy , gamma–gamma prime superalloys, IN-100 and LSHR, was established. For this purpose, isothermal, hot

Microstructural characteristics of high-temperature oxidation in nickel-base superalloy

International Nuclear Information System (INIS)

Khalid, F.A.

1997-01-01

Superalloys are used for aerospace and nuclear applications where they can withstand high-temperature and severe oxidizing conditions. High-temperature oxidation behavior of a nickel-base superalloy is examined using optical and scanning electron microscopical techniques. The morphology of the oxide layers developed is examined, and EDX microanalysis reveals diffusion of the elements across the oxide-metal interface. Evidence of internal oxidation is presented, and the role of structural defects is considered. The morphology of the oxide-metal interface formed in the specimens exposed in steam and air is examined to elucidate the mechanism of high-temperature oxidation

Morphology Dependent Flow Stress in Nickel-Based Superalloys in the Multi-Scale Crystal Plasticity Framework

Directory of Open Access Journals (Sweden)

Shahriyar Keshavarz

2017-11-01

Full Text Available This paper develops a framework to obtain the flow stress of nickel-based superalloys as a function of γ-γ’ morphology. The yield strength is a major factor in the design of these alloys. This work provides additional effects of γ’ morphology in the design scope that has been adopted for the model developed by authors. In general, the two-phase γ-γ’ morphology in nickel-based superalloys can be divided into three variables including γ’ shape, γ’ volume fraction and γ’ size in the sub-grain microstructure. In order to obtain the flow stress, non-Schmid crystal plasticity constitutive models at two length scales are employed and bridged through a homogenized multi-scale framework. The multi-scale framework includes two sub-grain and homogenized grain scales. For the sub-grain scale, a size-dependent, dislocation-density-based finite element model (FEM of the representative volume element (RVE with explicit depiction of the γ-γ’ morphology is developed as a building block for the homogenization. For the next scale, an activation-energy-based crystal plasticity model is developed for the homogenized single crystal of Ni-based superalloys. The constitutive models address the thermo-mechanical behavior of nickel-based superalloys for a large temperature range and include orientation dependencies and tension-compression asymmetry. This homogenized model is used to obtain the morphology dependence on the flow stress in nickel-based superalloys and can significantly expedite crystal plasticity FE simulations in polycrystalline microstructures, as well as higher scale FE models in order to cast and design superalloys.

MC Carbide Characterization in High Refractory Content Powder-Processed Ni-Based Superalloys

Science.gov (United States)

Antonov, Stoichko; Chen, Wei; Huo, Jiajie; Feng, Qiang; Isheim, Dieter; Seidman, David N.; Sun, Eugene; Tin, Sammy

2018-04-01

Carbide precipitates in Ni-based superalloys are considered to be desirable phases that can contribute to improving high-temperature properties as well as aid in microstructural refinement of the material; however, they can also serve as crack initiation sites during fatigue. To date, most of the knowledge pertaining to carbide formation has originated from assessments of cast and wrought Ni-based superalloys. As powder-processed Ni-based superalloys are becoming increasingly widespread, understanding the different mechanisms by which they form becomes increasingly important. Detailed characterization of MC carbides present in two experimental high Nb-content powder-processed Ni-based superalloys revealed that Hf additions affect the resultant carbide morphologies. This morphology difference was attributed to a higher magnitude of elastic strain energy along the interface associated with Hf being soluble in the MC carbide lattice. The composition of the MC carbides was studied through atom probe tomography and consisted of a complex carbonitride core, which was rich in Nb and with slight Hf segregation, surrounded by an Nb carbide shell. The characterization results of the segregation behavior of Hf in the MC carbides and the subsequent influence on their morphology were compared to density functional theory calculations and found to be in good agreement, suggesting that computational modeling can successfully be used to tailor carbide features.

Effects of cutting parameters on machinability characteristics of Ni-based superalloys: a review

Directory of Open Access Journals (Sweden)

Kaya Eren

2017-12-01

Full Text Available Nickel based superalloys offer high strength, corrosion resistance, thermal stability and superb thermal fatigue properties. However, they have been one of the most difficult materials to machine due to these properties. Although we are witnessing improved machining strategies with the developing machining, tooling and inspection technologies, machining of nickel based superalloys is still a challenging task due to in-process strains and post process part quality demands.

Phase-transformation and subgrain-deformation characteristics in a cobalt-based superalloy

International Nuclear Information System (INIS)

Benson, M.L.; Reetz, B.; Liaw, P.K.; Reimers, W.; Choo, H.; Brown, D.W.; Saleh, T.A.; Klarstrom, D.L.

2011-01-01

Research highlights: → The mechanical behavior of a cobalt-based superalloy was investigated. → Two diffraction techniques were used to study deformation mechanisms of materials. → In-situ neutron diffraction provides the volume-averaged information. → The peak-profile analysis reveals the information on a subgrain level. → The material exhibited a transformation texture for the HCP phase under loading. - Abstract: A complimentary set of experiments, in situ neutron diffraction and ex situ synchrotron X-ray diffraction, were used to study the phase-transformation and subgrain-deformation characteristics of a cobalt-based superalloy. The neutron diffraction indicated a strain-induced phase transformation in the cobalt-based superalloy under uniaxial tension and compression. The synchrotron X-ray diffraction revealed stacking-fault accumulation and twinning under the same loading conditions. The extent of transformation was found to be greater under tension than under compression. Tensile plastic strains below 2% were accommodated by the stacking-fault creation, while those greater than 2% were accommodated by the phase transformation. Twinning was found to be more active under compressive loading than under tensile loading.

High Temperature Degradation of Powder-processed Ni-based Superalloy

Czech Academy of Sciences Publication Activity Database

Luptáková, Natália; Pizúrová, Naděžda; Roupcová, Pavla; Dymáček, Petr

2015-01-01

Roč. 22, č. 2 (2015), s. 85-94 ISSN 1335-0803 Institutional support: RVO:68081723 Keywords : powder materials * polycrystalline Ni-based superalloy * creep machine grips * oxidation Subject RIV: JG - Metallurgy

Crystallographic, microstructure and mechanical characteristics of dynamically processed IN718 superalloy

Energy Technology Data Exchange (ETDEWEB)

Sharma, A.D., E-mail: ads.hpu@gmail.com [Department of Physics, Himachal Pradesh University, Shimla 171005 (India); Sharma, A.K. [Terminal Ballistics Research Laboratory, Chandigarh 160030 (India); Thakur, N. [Department of Physics, Himachal Pradesh University, Shimla 171005 (India)

2014-06-01

Highlights: • Measurement of detonation velocity and compaction of powder are achieved together. • A plastic explosive detonation results into dense compacts without grain-growth. • We have studied crystallographic, micromechanical and microstructural features. • The results show no segregation within the compacts. • Density (98%), microhardness (470 ± 3)H{sub v}, microstrain (0.3%), UTS (806 MPa) are obtained. - Abstract: Dynamic consolidation of IN718 superalloy powder without grain-growth and negligible density gradient is accomplished through explosively generated shock wave loading. The compaction of powder and measurement of detonation velocity are achieved successfully in a single-shot experiment by employing instrumented detonics. A plastic explosive having a detonation velocity of the order of 7.1 km/s in a direct proximity with superalloy powder is used for the consolidation process. The compacted specimens are examined for structural, microstructure and mechanical characteristics. X-ray diffraction (XRD) study suggests intact crystalline structure of the compacts. A small micro-strain (0.26%) is observed by using Williamson–Hall method. Wavelength dispersive spectroscopy indicates no segregation within the shock processed superalloy compacted specimens. The monoliths investigated for fractography by using field emission scanning electron microscopy (FE-SEM) show original dendritic structure accompanied by re-solidified molten regions across the interparticle boundaries. Depth-sensing indentations (at 1.96 N) on compacted specimens show excellent micro-hardness of the order of (470 ± 3)H{sub v}. Tensile and compressive strengths of the superalloy monolith are observed to be 806 and 822 MPa, respectively.

Phase Stability of a Powder Metallurgy Disk Superalloy

Science.gov (United States)

Gabb, Timothy P.; Gayda, John; Kantzos, P.; Telesman, Jack; Gang, Anita

2006-01-01

Advanced powder metallurgy superalloy disks in aerospace turbine engines now entering service can be exposed to temperatures approaching 700 C, higher than those previously encountered. They also have higher levels of refractory elements, which can increase mechanical properties at these temperatures but can also encourage phase instabilities during service. Microstructural changes including precipitation of topological close pack phase precipitation and coarsening of existing gamma' precipitates can be slow at these temperatures, yet potentially significant for anticipated disk service times exceeding 1,000 h. The ability to quantify and predict such potential phase instabilities and degradation of capabilities is needed to insure structural integrity and air worthiness of propulsion systems over the full life cycle. A prototypical advanced disk superalloy was subjected to high temperature exposures, and then evaluated. Microstructural changes and corresponding changes in mechanical properties were quantified. The results will be compared to predictions of microstructure modeling software.

Effects of electrical discharge surface modification of superalloy Haynes 230 with aluminum and molybdenum on oxidation behavior

International Nuclear Information System (INIS)

Bai, C.-Y.

2007-01-01

The effects of the electrical discharge alloying (EDA) process on improving the high temperature oxidation resistance of the Ni-based superalloy Haynes 230 have been investigated. The 85 at.% Al and 15 at.% Mo composite electrode provided the surface alloying materials. An Al-rich layer is produced on the surface of the EDA specimen alloyed with positive electrode polarity, whereas, many discontinuous piled layers are attached to the surface of the EDA superalloy when negative electrode polarity is selected. The oxidation resistance of the specimen alloyed with positive electrode polarity is better than that of the unalloyed superalloy, and the effective temperature of oxidation resistance of the alloyed layer can be achieved to 1100 o C. Conversely, the oxidation resistance of the other EDA specimen alloyed with negative electrode polarity is even worse than that of the unalloyed superalloy

MGI-oriented High-throughput Measurement of Interdiffusion Coefficient Matrices in Ni-based Superalloys

Directory of Open Access Journals (Sweden)

TANG Ying

2017-01-01

Full Text Available One of the research hotspots in the field of high-temperature alloys was to search the substitutional elements for Re in order to prepare the single-crystal Ni-based superalloys with less or even no Re addition. To find the elements with similar or even lower diffusion coefficients in comparison with that of Re was one of the effective strategies. In multicomponent alloys, the interdiffusivity matrix were used to comprehensively characterize the diffusion ability of any alloying elements. Therefore, accurate determination of the composition-dependant and temperature-dependent interdiffusivities matrices of different elements in γ and γ' phases of Ni-based superalloys was high priority. The paper briefly introduces of the status of the interdiffusivity matrices determination in Ni-based superalloys, and the methods for determining the interdiffusivities in multicomponent alloys, including the traditional Matano-Kirkaldy method and recently proposed numerical inverse method. Because the traditional Matano-Kirkaldy method is of low efficiency, the experimental reports on interdiffusivity matrices in ternary and higher order sub-systems of the Ni-based superalloys were very scarce in the literature. While the numerical inverse method newly proposed in our research group based on Fick's second law can be utilized for high-throughput measurement of accurate interdiffusivity matrices in alloys with any number of components. After that, the successful application of the numerical inverse method in the high-throughput measurement of interdiffusivity matrices in alloys is demonstrated in fcc (γ phase of the ternary Ni-Al-Ta system. Moreover, the validation of the resulting composition-dependant and temperature-dependent interdiffusivity matrices is also comprehensively made. Then, this paper summarizes the recent progress in the measurement of interdiffusivity matrices in γ and γ' phases of a series of core ternary Ni-based superalloys achieved in

Near-Infrared Phosphorus-Substituted Rhodamine with Emission Wavelength above 700 nm for Bioimaging.

Science.gov (United States)

Chai, Xiaoyun; Cui, Xiaoyan; Wang, Baogang; Yang, Fan; Cai, Yi; Wu, Qiuye; Wang, Ting

2015-11-16

Phosphorus has been successfully fused into a classic rhodamine framework, in which it replaces the bridging oxygen atom to give a series of phosphorus-substituted rhodamines (PRs). Because of the electron-accepting properties of the phosphorus moiety, which is due to effective σ*-π* interactions and strengthened by the inductivity of phosphine oxide, PR exhibits extraordinary long-wavelength fluorescence emission, elongating to the region above 700 nm, with bathochromic shifts of 140 and 40 nm relative to rhodamine and silicon-substituted rhodamine, respectively. Other advantageous properties of the rhodamine family, including high molar extinction coefficient, considerable quantum efficiency, high water solubility, pH-independent emission, great tolerance to photobleaching, and low cytotoxicity, stay intact in PR. Given these excellent properties, PR is desirable for NIR-fluorescence imaging in vivo. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hot deformation behavior of delta-processed superalloy 718

Energy Technology Data Exchange (ETDEWEB)

Wang, Y., E-mail: wangyanhit@yahoo.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); School of Aeronautics and Astronautics, Central South University, Changsha 410083 (China); Shao, W.Z.; Zhen, L.; Zhang, B.Y. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2011-03-25

Research highlights: {yields} The peak stress for hot deformation can be described by the Z parameter. {yields} The grain size of DRX was inversely proportional to the Z parameter. {yields} The dissolution of {delta} phases was greatly accelerated under hot deformation. {yields}The {delta} phase stimulated nucleation can serve as the main DRX mechanism. - Abstract: Flow stress behavior and microstructures during hot compression of delta-processed superalloy 718 at temperatures from 950 to 1100 deg. C with strain rates of 10{sup -3} to 1 s{sup -1} were investigated by optical microscopy (OM), electron backscatter diffraction (EBSD) technique and transmission electron microscopy (TEM). The relationship between the peak stress and the deformation conditions can be expressed by a hyperbolic-sine type equation. The activation energy for the delta-processed superalloy 718 is determined to be 467 kJ/mol. The change of the dominant deformation mechanisms leads to the decrease of stress exponent and the increase of activation energy with increasing temperature. The dynamically recrystallized grain size is inversely proportional to the Zener-Hollomon (Z) parameter. It is found that the dissolution rate of {delta} phases under hot deformation conditions is much faster than that under static conditions. Dislocation, vacancy and curvature play important roles in the dissolution of {delta} phases. The main nucleation mechanisms of dynamic recrystallization (DRX) for the delta-processed superalloy 718 include the bulging of original grain boundaries and the {delta} phase stimulated DRX nucleation, which is closely related to the dissolution behavior of {delta} phases under certain deformation conditions.

Analysis of laser beam weldability of Inconel 738 superalloy

International Nuclear Information System (INIS)

Egbewande, A.T.; Buckson, R.A.; Ojo, O.A.

2010-01-01

The susceptibility of pre-weld heat treated laser beam welded IN 738 superalloy to heat affected zone (HAZ) cracking was studied. A pre-weld heat treatment that produced the minimal grain boundary liquation resulted in a higher level of cracking compared to those with more intergranular liquation. This deviation from the general expectation of influence of intergranular liquation extent on HAZ microfissuring is attributable to the reduction in the ability of the base alloy to accommodate welding tensile stress that accompanied a pre-weld heat treatment condition designed to minimize intergranular liquation. Furthermore, in contrast to what has been generally reported in other nickel-based superalloys, a decrease in laser welding speed resulted in increased HAZ cracking in the IN 738, which can be attributed to exacerbated process instability at lower welding speeds.

Effects of cobalt in nickel-base superalloys

Science.gov (United States)

Tien, J. K.; Jarrett, R. N.

1983-01-01

The role of cobalt in a representative wrought nickel-base superalloy was determined. The results show cobalt affecting the solubility of elements in the gamma matrix, resulting in enhanced gamma' volume fraction, in the stabilization of MC-type carbides, and in the stabilization of sigma phase. In the particular alloy studied, these microstructural and microchemistry changes are insufficient in extent to impact on tensile strength, yield strength, and in the ductilities. Depending on the heat treatment, creep and stress rupture resistance can be cobalt sensitive. In the coarse grain, fully solutioned and aged condition, all of the alloy's 17% cobalt can be replaced by nickel without deleteriously affecting this resistance. In the fine grain, partially solutioned and aged condition, this resistance is deleteriously affected only when one-half or more of the initial cobalt content is removed. The structure and property results are discussed with respect to existing theories and with respect to other recent and earlier findings on the impact of cobalt, if any, on the performance of nickel-base superalloys.

Low-Cobalt Powder-Metallurgy Superalloy

Science.gov (United States)

Harf, F. H.

1986-01-01

Highly-stressed jet-engine parts made with less cobalt. Udimet 700* (or equivalent) is common nickel-based superalloy used in hot sections of jet engines for many years. This alloy, while normally used in wrought condition, also gas-atomized into prealloyed powder-metallurgy (PM) product. Product can be consolidated by hot isostatically pressing (HIPPM condition) and formed into parts such as turbine disk. Such jet-engine disks "see" both high stresses and temperatures to 1,400 degrees F (760 degrees C).

3D imaging and characterisation of strengthening particles in inconel 718 using FIB tomography

Energy Technology Data Exchange (ETDEWEB)

Kruk, Adam; Gruszczynski, Adam; Czyrska-Filemonowicz, Aleksandra [AGH University of Science and Technology, Faculty of Metals Engineering and Industrial Computer Science, Al. A. Mickiewicza 30, 30-059 Krakow (Poland)

2011-07-01

The Inconel 718 is a commercial nickel-base superalloy, widely used for critical pieces in turbine engines. Its microstructure consists of the {gamma} matrix and strengthening coherent nanoparticles {gamma}' and {gamma}''. In the present work FIB tomography technique was used for imaging and characterisation of strengthening particles. FIB tomography is based on a serial sectioning procedure using a FIB/SEM dual beam workstation. Repeated removal of layers as thin as several nm for some hundred times allows to investigate at total a volume of some {mu}m3 with a voxel size as 2.5 nm x 2.5 nm x 2.5 nm. 3D mapping of nanoparticles with high Z-resolution by serial FIB slicing (in a distance of about 2.5 nm) and SEM imaging was performed. Ga ion beam at 30 kV was used to perform a precise in-situ milling. The SEM images at accelerating voltage 1.5 kV were taken with using ESB detector. The real 3D-data of precipitates obtained by FIB tomography, open a new possibility for microstructure analysis of materials for industrial applications.

Microstructural Characterization and Modeling of SLM Superalloy 718

Science.gov (United States)

Smith, Tim M.; Sudbrack, Chantal K.; Bonacuse, Pete; Rogers, Richard

2017-01-01

Superalloy 718 is an excellent candidate for selective laser melting (SLM) fabrication due to a combination of excellent mechanical properties and workability. Predicting and validating the microstructure of SLM-fabricated Superalloy 718 after potential post heat-treatment paths is an important step towards producing components comparable to those made using conventional methods. At present, obtaining accurate volume fraction and size measurements of gamma-double-prime, gamma-prime and delta precipitates has been challenging due to their size, low volume fractions, and similar chemistries. A technique combining high resolution distortion corrected SEM imaging and with x-ray energy dispersive spectroscopy has been developed to accurately and independently measure the size and volume fractions of the three precipitates. These results were further validated using x-ray diffraction and phase extraction methods and compared to the precipitation kinetics predicted by PANDAT and JMatPro. Discrepancies are discussed in context of materials properties, model assumptions, sampling, and experimental errors.

Nickel-base superalloy powder metallurgy: state-of-the-art

International Nuclear Information System (INIS)

Allen, M.M.; Athey, R.L.; Moore, J.B.

1975-01-01

Development of powder metallurgical methods for fabrication of Ni-base superalloy turbine engine disks is reviewed. Background studies are summarized and current state-of-art is discussed for the F100 jet engine, advanced applications, and forging processes

Detection of creep damage in a nickel base superalloy using NDE techniques

International Nuclear Information System (INIS)

Carreon, H.; Mora, B.; Barrera, G.

2009-10-01

Due to elevated temperatures, excessive stresses and severed corrosion conditions, turbine engine components are subject to creep processes that limit the components life such as a turbine bucket. The failure mechanism of a turbine bucket is related primarily to creep and corrosion and secondarily to thermal fatigue. As a result, it is desirable to assess the current conditions of such turbine component. This study uses the eddy current nondestructive evaluation technique in an effort to monitor the creep damage in a nickel base super-alloy, turbine bucket after service. The experimental results show an important electrical conductivity variation in eddy current images on the creep damage zone of nickel base super-alloy samples cut from a turbine bucket. Thermoelectric power measurements were also conducted in order to obtain a direct correlation between the presence of material changes due to creep damage and the electrical conductivity measurements. This research work shows an alternative non-destructive method in order to detect creep damage in a nickel base super-alloy turbine bucket. (Author)

Degradation of creep properties in a long-term thermally exposed nickel base superalloy

International Nuclear Information System (INIS)

Zrnik, J.; Strunz, P.; Vrchovinsky, V.; Muransky, O.; Novy, Z.; Wiedenmann, A.

2004-01-01

When exposed for long time at elevated temperatures of 430 and 650 deg. C the nickel base superalloy EI 698 VD can experience a significant decrease in creep resistance. The cause of the creep degradation of nickel base superalloy is generally attributed to the microstructural instability at prolonged high temperature exposure. In this article, the creep-life data, generated on long thermally exposed nickel base superalloy EI698 VD were related to the local microstructural changes observed using SEM and TEM analysing techniques. While structure analysis provided supporting evidence concerning the changes associated with grain boundary carbide precipitation, no persuasive evidence of a morphological and/or dimensional gamma prime change was showed. For clarifying of the role of gamma prime precipitates on alloy on creep degradation, the SANS (small angle neutron scattering) experiment was crucial in the characterization of the bulk-averaged gamma prime morphology and its size distribution with respect to the period of thermal exposure

Proceedings of the Conference on Refractory Alloying Elements in Superalloys

International Nuclear Information System (INIS)

1984-01-01

Some papers about the use of refractory metals in superalloys are presented. Mechanical properties, thermodynamics properties, use for nuclear fuels and corrosion resistance of those alloys are studied. (E.G.) [pt

Effect of tensile mean stress on fatigue behavior of single-crystal and directionally solidified superalloys

Science.gov (United States)

Kalluri, Sreeramesh; Mcgaw, Michael A.

1990-01-01

Two nickel base superalloys, single crystal PWA 1480 and directionally solidified MAR-M 246 + Hf, were studied in view of the potential usage of the former and usage of the latter as blade materials for the turbomachinery of the space shuttle main engine. The baseline zero mean stress (ZMS) fatigue life (FL) behavior of these superalloys was established, and then the effect of tensile mean stress (TMS) on their FL behavior was characterized. At room temperature these superalloys have lower ductilities and higher strengths than most polycrystalline engineering alloys. The cycle stress-strain response was thus nominally elastic in most of the fatigue tests. Therefore, a stress range based FL prediction approach was used to characterize both the ZMS and TMS fatigue data. In the past, several researchers have developed methods to account for the detrimental effect of tensile mean stress on the FL for polycrystalline engineering alloys. However, the applicability of these methods to single crystal and directionally solidified superalloys has not been established. In this study, these methods were applied to characterize the TMS fatigue data of single crystal PWA 1480 and directionally solidified MAR-M 246 + Hf and were found to be unsatisfactory. Therefore, a method of accounting for the TMS effect on FL, that is based on a technique proposed by Heidmann and Manson was developed to characterize the TMS fatigue data of these superalloys. Details of this method and its relationship to the conventionally used mean stress methods in FL prediction are discussed.

Erosion–corrosion behaviour of Ni-based superalloy Superni-75

Indian Academy of Sciences (India)

The super-heater and re-heater tubes of the boilers used in thermal power plants are ... mechanism, resulting in the tube wall thinning and premature failure. The nickel-based superalloys can be used as boiler tube materials to increase the ...

Rapid preparation of ceramic moulds for medium-sized superalloy castings with magnesia-phosphate-bonded bauxite-mullite investments

Directory of Open Access Journals (Sweden)

Li Tingzhong

2010-11-01

Full Text Available Phosphate-bonded investments have already been widely utilized in dental restoration and micro-casting of artistic products for its outstanding rapid setting and high strength. However, the rapid setting rate of investment slurry has up to now been a barrier to extend the use of such slurry in preparation of medium-sized ceramic moulds. This paper proposes a new process of rapid fabrication of magnesia-phosphate-bonded investment ceramic moulds for medium-sized superalloy castings utilizing bauxite and mullite as refractory aggregates. In order to determine the properties of magnesia-phosphate-bonded bauxite-mullite investments (MPBBMI, a series of experiments were conducted, including modification of the workable time of slurry by liquid(mL/powder(g(L/P ratio and addition of boric acid as retard agent and sodium tri-polyphosphate (STP as strengthening agent, and adjustment of bauxite (g/mullite(g(B/M ratio for mechanical strength. Mechanical vibration was applied to improve initial setting time and fluidity when pouring investment slurry; then an intermediate size ceramic mould for superalloy castings was manufactured by means of this rapid preparing process with MPBBMI material. The results showed that the MPBBMI slurry exhibits proper initial setting time and excellent fluidity when the L/P ratio is 0.64 and the boric acid content is 0.88wt.%. The fired specimens made from the MPBBMI material demonstrated adequate compression strength to withstand impact force of molten metal when the B/M ratio is 0.89 and the STP content is 0.92wt.%. The experimental results confirmed the feasibility of the proposed rapid fabricating process for medium-sized ceramic moulds with MPBBMI material by appropriate measures.

Gamma prime precipitation modeling and strength responses in powder metallurgy superalloys

Science.gov (United States)

Mao, Jian

Precipitation-hardened nickel-based superalloys have been widely used as high temperature structural materials in gas turbine engine applications for more than 50 years. Powder metallurgy (P/M) technology was introduced as an innovative manufacturing process to overcome severe segregation and poor workability of alloys with high alloying contents. The excellent mechanical properties of P/M superalloys also depend upon the characteristic microstructures, including grain size and size distribution of gamma' precipitates. Heat treatment is the most critical processing step that has ultimate influences on the microstructure, and hence, on the mechanical properties of the materials. The main objective of this research was to study the gamma ' precipitation kinetics in various cooling circumstances and also study the strength response to the cooling history in two model alloys, Rne88DT and U720LI. The research is summarized below: (1) An experimental method was developed to allow accurate simulation and control of any desired cooling profile. Two novel cooling methods were introduced: continuous cooling and interrupt cooling. Isothermal aging was also carried out. (2) The growth and coarsening kinetics of the cooling gamma' precipitates were experimentally studied under different cooling and aging conditions, and the empirical equations were established. It was found that the cooling gamma' precipitate versus the cooling rate follows a power law. The gamma' precipitate size versus aging time obeys the LSW cube law for coarsening. (3) The strengthening of the material responses to the cooling rate and the decreasing temperature during cooling was investigated in both alloys. The tensile strength increases with the cooling rate. In addition, the non-monotonic response of strength versus interrupt temperature is of great interest. (4) An energy-driven model integrated with the classic growth and coarsen theories was successfully embedded in a computer program developed to

Alloying effects of refractory elements in the dislocation of Ni-based single crystal superalloys

Directory of Open Access Journals (Sweden)

Shiyu Ma

2016-12-01

Full Text Available The alloying effects of W, Cr and Re in the [100] (010 edge dislocation cores (EDC of Ni-based single crystal superalloys are investigated using first-principles based on the density functional theory (DFT. The binding energy, Mulliken orbital population, density of states, charge density and radial distribution functions are discussed, respectively. It is clearly demonstrated that the addition of refractory elements improves the stability of the EDC systems. In addition, they can form tougher bonds with their nearest neighbour (NN Ni atoms, which enhance the mechanical properties of the Ni-based single crystal superalloys. Through comparative analysis, Cr-doped system has lower binding energy, and Cr atom has evident effect to improve the systemic stability. However, Re atom has the stronger alloying effect in Ni-based single crystal superalloys, much more effectively hindering dislocation motion than W and Cr atoms.

Development of superalloys for 1700 C ultra-efficient gas turbines

Energy Technology Data Exchange (ETDEWEB)

Harada, Hiroshi [National Institute for Materials Science, Tsukuba, Ibaraki (Japan). High Temperature Materials Center

2010-07-01

Mitigation of global warming is one of the most outstanding issues for the humankind. The Japanese government announced that it will reduce its greenhouse gas emissions by 25% from the 1990 level by 2020 as a medium-term goal. One of the promising approaches to achieving this is to improve the efficiency of thermal power plants emitting one-third of total CO{sub 2} gas in Japan. The key to improving the thermal efficiency is high temperature materials with excellent temperature capabilities allowing higher inlet gas temperatures. In this context, new single crystal superalloys for turbine blades and vanes, new coatings and turbine disk superalloys have been successfully developed for various gas turbine applications, typically 1700 C ultra-efficient gas turbines for next generation combine cycle power plants. (orig.)

[Effects of phosphorus sources on phosphorus fractions in rhizosphere soil of wild barley genotypes with high phosphorus utilization efficiency].

Science.gov (United States)

Cai, Qiu-Yan; Zhang, Xi-Zhou; Li, Ting-Xuan; Chen, Guang-Deng

2014-11-01

High P-efficiency (IS-22-30, IS-22-25) and low P-efficiency (IS-07-07) wild barley cultivars were chosen to evaluate characteristics of phosphorus uptake and utilization, and properties of phosphorus fractions in rhizosphere and non-rhizosphere in a pot experiment with 0 (CK) and 30 mg P · kg(-1) supplied as only Pi (KH2PO4), only Po (phytate) or Pi + Po (KH2PO4+ phytate). The results showed that dry matter and phosphorus accumulation of wild barley in the different treatments was ranked as Pi > Pi + Po > Po > CK. In addition, dry matter yield and phosphorus uptake of wild barley with high P-efficiency exhibited significantly greater than that with low P-efficiency. The concentration of soil available phosphorus was significantly different after application of different phosphorus sources, which was presented as Pi > Pi + Po > Po. The concentration of soil available phosphorus in high P-efficiency wild barley was significantly higher than that of low P-efficiency in the rhizosphere soil. There was a deficit in rhizosphere available phosphorus of high P-efficiency wild barley, especially in Pi and Pi+Po treatments. The inorganic phosphorus fractions increased with the increasing Pi treatment, and the concentrations of inorganic phosphorus fractions in soil were sorted as follows: Ca10-P > O-P > Fe-P > Al-P > Ca2-P > Ca8-P. The contents of Ca2-P and Ca8-P for high P-efficiency wild barley showed deficits in rhizosphere soil under each phosphorus source treatment. In addition, enrichment of Al-P and Fe-P was observed in Pi treatment in rhizosphere soil. The concentrations of organic phosphorus fractions in soil were sorted as follows: moderate labile organic phosphorus > moderate resistant, resistant organic phosphorus > labile organic phosphorus. The labile and moderate labile organic phosphorus enriched in rhizosphere soil and the greatest enrichment appeared in Pi treatment. Furthermore, the concentrations of moderate resistant organic phosphorus and resistant

Thermomechanical behavior of different Ni-base superalloys during cyclic loading at elevated temperatures

Directory of Open Access Journals (Sweden)

Huber Daniel

2014-01-01

Full Text Available The material behavior of three Ni-base superalloys (Inconel® 718, Allvac® 718PlusTM and Haynes® 282® during in-phase cyclic mechanical and thermal loading was investigated. Stress controlled thermo-mechanical tests were carried out at temperatures above 700 ∘C and different levels of maximum compressive stress using a Gleeble® 3800 testing system. Microstructure investigations via light optical microscopy (LOM and field emission gun scanning electron microscopy (FEG-SEM as well as numerical precipitation kinetics simulations were performed to interpret the obtained results. For all alloys, the predominant deformation mechanism during deformation up to low plastic strains was identified as dislocation creep. The main softening mechanism causing progressive increase of plastic strain after preceding linear behavior is suggested to be recrystallization facilitated by coarsening of grain boundary precipitates. Furthermore, coarsening and partial transformation of strengthening phases was observed. At all stress levels, Haynes® 282® showed best performance which is attributable to its stable microstructure containing a high phase fraction of small, intermetallic precipitates inside grains and different carbides evenly distributed along grain boundaries.

High-cycle fatigue behavior of Co-based superalloy 9CrCo at elevated temperatures

OpenAIRE

Wan, Aoshuang; Xiong, Junjiang; Lyu, Zhiyang; Li, Kuang; Du, Yisen; Chen, Kejiao; Man, Ziyu

2016-01-01

A modified model is developed to characterize and evaluate high-cycle fatigue behavior of Co-based superalloy 9CrCo at elevated temperatures by considering the stress ratio effect. The model is informed by the relationship surface between maximum nominal stress, stress ratio and fatigue life. New formulae are derived to deal with the test data for estimating the parameters of the proposed model. Fatigue tests are performed on Co-based superalloy 9CrCo subjected to constant amplitude loading a...

Preparation of phosphorus targets using the compound phosphorus nitride

International Nuclear Information System (INIS)

Maier-Komor, P.

1987-01-01

Commercially available phosphorus nitride (P 3 N 5 ) shows a high oxygen content. Nevertheless, this material is attractive for use as phosphorus targets in experiments where red phosphorus would disappear due to its high vapor pressure and where a metal partner in the phosphide must be excluded due to its high atomic number. Methods are described to produce phosphorus nitride targets by vacuum evaporation condensation. (orig.)

The precipitation behavior of superalloy ATI Allvac 718Plus

Energy Technology Data Exchange (ETDEWEB)

Zickler, Gerald A.; Schnitzer, Ronald; Leitner, Harald [Department of Physical Metallurgy and Materials Testing, Christian Doppler Laboratory Early Stages of Precipitation, Montanuniversitaet Leoben (Austria); Radis, Rene [Christian Doppler Laboratory Early Stages of Precipitation, Institute of Materials Science and Technology, Vienna University of Technology (Austria); Institute for Materials Science and Welding, Graz University of Technology (Austria); Kozeschnik, Ernst [Christian Doppler Laboratory Early Stages of Precipitation, Institute of Materials Science and Technology, Vienna University of Technology (Austria); Stockinger, Martin [Boehler Schmiedetechnik GmbH and Co. KG., Kapfenberg (Austria)

2010-03-15

ATI Allvac 718Plus is a novel nickel-based superalloy, which was designed for heavy-duty applications in aerospace gas turbines. The precipitation kinetics of the intermetallic {delta} (Ni{sub 3}Nb) and {gamma}' (Ni{sub 3}(Al,Ti)) phases in this alloy are of scientific as well as technological interest because of their significant influence on the mechanical properties. Important parameters like grain size are controlled by coarse {delta} precipitates located at grain boundaries, whereas small {gamma}' precipitates are responsible for strengthening by precipitation hardening. In the present study, the microstructure is investigated by three-dimensional atom probe tomography and simulated by computer modeling using the thermo-kinetic software MatCalc. The results of numerical simulations and experimental data are compared and critically discussed. It is shown that the chemical compositions of the phases change during isothermal aging, and the precipitation kinetics of {delta} and {gamma}' phases interact with each other as shown in a time temperature precipitation (TTP) plot. The TTP plot shows C-shaped curves with characteristic discontinuities in the temperature range, where simultaneous and concurrent precipitation of the {delta} and {gamma}' phases occurs. This leads to a competition in the diffusion of Nb and Al, which are partly present in both phases. Thus, the present study gives important information on heat treatments for ATI Allvac 718Plus in order to achieve the desired microstructure and mechanical properties. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Fabrication development for ODS-superalloy, air-cooled turbine blades

Science.gov (United States)

Moracz, D. J.

1984-01-01

MA-600 is a gamma prime and oxide dispersion strengthened superalloy made by mechanical alloying. At the initiation of this program, MA-6000 was available as an experimental alloy only and did not go into production until late in the program. The objective of this program was to develop a thermal-mechanical-processing approach which would yield the necessary elongated grain structure and desirable mechanical properties after conventional press forging. Forging evaluations were performed to select optimum thermal-mechanical-processing conditions. These forging evaluations indicated that MA-6000 was extremely sensitive to die chilling. In order to conventionally hot forge the alloy, an adherent cladding, either the original extrusion can or a thick plating, was required to prevent cracking of the workpiece. Die design must reflect the requirement of cladding. MA-6000 was found to be sensitive to the forging temperature. The correct temperature required to obtain the proper grain structure after recrystallization was found to be between 1010-1065 C (1850-1950 F). The deformation level did not affect subsequent crystallization; however, sharp transition areas in tooling designs should be avoided in forming a blade shape because of the potential for grain structure discontinuities. Starting material to be used for forging should be processed so that it is capable of being zone annealed to a coarse elongated grain structure as bar stock. This conclusion means that standard processed bar materials can be used.

Effects of helium impurities on superalloys

International Nuclear Information System (INIS)

Selle, J.E.

1977-07-01

A review of the literature on the effects of helium impurities on superalloys at elevated temperatures was undertaken. The actual effects of these impurities vary depending on the alloy, composition of the gas atmosphere, and temperature. In general, exposure in helium produces significant but not catastrophic changes in the structure and properties of the alloys. The effects of these treatments on the structure, creep, fatigue, and mechanical properties of the various alloys are reviewed and discussed. Suggestions for future work are presented

First-principles calculations for the elastic properties of Ni-base model superalloys: Ni/Ni3Al multilayers

International Nuclear Information System (INIS)

Yun-Jiang, Wang; Chong-Yu, Wang

2009-01-01

A model system consisting of Ni[001](100)/Ni 3 Al[001](100) multi-layers are studied using the density functional theory in order to explore the elastic properties of single crystal Ni-based superalloys. Simulation results are consistent with the experimental observation that rafted Ni-base superalloys virtually possess a cubic symmetry. The convergence of the elastic properties with respect to the thickness of the multilayers are tested by a series of multilayers from 2γ'+2γ to 10γ'+10γ atomic layers. The elastic properties are found to vary little with the increase of the multilayer's thickness. A Ni/Ni 3 Al multilayer with 10γ'+10γ atomic layers (3.54 nm) can be used to simulate the mechanical properties of Ni-base model superalloys. Our calculated elastic constants, bulk modulus, orientation-dependent shear modulus and Young's modulus, as well as the Zener anisotropy factor are all compatible with the measured results of Ni-base model superalloys R1 and the advanced commercial superalloys TMS-26, CMSX-4 at a low temperature. The mechanical properties as a function of the γ' phase volume fraction are calculated by varying the proportion of the γ and γ' phase in the multilayers. Besides, the mechanical properties of two-phase Ni/Ni 3 Al multilayer can be well predicted by the Voigt–Reuss–Hill rule of mixtures. (classical areas of phenomenology)

A comparative study of the corrosion resistance of incoloy MA 956 and PM 2000 superalloys

Directory of Open Access Journals (Sweden)

Maysa Terada

2010-12-01

Full Text Available Austenitic stainless steels, titanium and cobalt alloys are widely used as biomaterials. However, new medical devices require innovative materials with specific properties, depending on their application. The magnetic properties are among the properties of interest for some biomedical applications. However, due to the interaction of magnetic materials with Magnetic Resonance Image equipments they might used only as not fixed implants or for medical devices. The ferromagnetic superalloys, Incoloy MA 956 and PM 2000, produced by mechanical alloying, have similar chemical composition, high corrosion resistance and are used in high temperature applications. In this study, the corrosion resistance of these two ferritic superalloys was compared in a phosphate buffer solution. The electrochemical results showed that both superalloys are passive in this solution and the PM 2000 present a more protective passive film on it associated to higher impedances than the MA 956.

Sustainable Phosphorus Measures: Strategies and Technologies for Achieving Phosphorus Security

Directory of Open Access Journals (Sweden)

Stuart White

2013-01-01

Full Text Available Phosphorus underpins the world’s food systems by ensuring soil fertility, maximising crop yields, supporting farmer livelihoods and ultimately food security. Yet increasing concerns around long-term availability and accessibility of the world’s main source of phosphorus—phosphate rock, means there is a need to investigate sustainable measures to buffer the world’s food systems against the long and short-term impacts of global phosphorus scarcity. While the timeline of phosphorus scarcity is contested, there is consensus that more efficient use and recycling of phosphorus is required. While the agricultural sector will be crucial in achieving this, sustainable phosphorus measures in sectors upstream and downstream of agriculture from mine to fork will also need to be addressed. This paper presents a comprehensive classification of all potential phosphorus supply- and demand-side measures to meet long-term phosphorus needs for food production. Examples range from increasing efficiency in the agricultural and mining sector, to technologies for recovering phosphorus from urine and food waste. Such measures are often undertaken in isolation from one another rather than linked in an integrated strategy. This integrated approach will enable scientists and policy-makers to take a systematic approach when identifying potential sustainable phosphorus measures. If a systematic approach is not taken, there is a risk of inappropriate investment in research and implementation of technologies and that will not ultimately ensure sufficient access to phosphorus to produce food in the future. The paper concludes by introducing a framework to assess and compare sustainable phosphorus measures and to determine the least cost options in a given context.

Double minimum creep of single crystal Ni-base superalloys

Czech Academy of Sciences Publication Activity Database

WU, X.; Wollgramm, P.; Somsen, C.; Dlouhý, Antonín; Kostka, A.; Eggeler, G.

2016-01-01

Roč. 112, JUN (2016), s. 242-260 ISSN 1359-6454 R&D Projects: GA ČR(CZ) GA14-22834S Institutional support: RVO:68081723 Keywords : Single crystal Ni-base superalloys * Primary creep * Transmission electron microscopy * Dislocations * Stacking faults Subject RIV: JG - Metallurgy Impact factor: 5.301, year: 2016

Hot isostatic pressing of single-crystal nickel-base superalloys: Mechanism of pore closure and effect on Mechanical properties

Directory of Open Access Journals (Sweden)

Epishin Alexander I.

2014-01-01

Full Text Available Pore annihilation was investigated in the single-crystal nickel-base superalloy CMSX-4. HIP tests at 1288 °C/103 MPa were interrupted at different times, then the specimens were investigated by TEM, metallography and density measurements. The kinetics of pore annihilation was determined. The pore closure mechanism was identified as plastic deformation on the octahedral slip systems. A model describing the kinetics of pore closure has been developed on the base of crystal plasticity and large strain theory. Mechanical tests with the superalloy CMSX-4 and the Ru-containing superalloy VGM4 showed, that HIP significantly increases the fatigue life at low temperatures but has no effect on creep strength.

Microstructure evolution during dynamic recrystallization of hot deformed superalloy 718

International Nuclear Information System (INIS)

Wang, Y.; Shao, W.Z.; Zhen, L.; Zhang, X.M.

2008-01-01

Microstructure evolution during dynamic recrystallization (DRX) of superalloy 718 was studied by optical microscope and electron backscatter diffraction (EBSD) technique. Compression tests were performed at different strains at temperatures from 950 deg. C to 1120 deg. C with a strain rate of 10 -1 s -1 . Microstructure observations show that the recrystallized grain size as well as the fraction of new grains increases with the increasing temperature. A power exponent relationship is obtained between the dynamically recrystallized grain size and the peak stress. It is found that different nucleation mechanisms for DRX are operated in hot deformed superalloy 718, which is closely related to deformation temperatures. DRX nucleation and development are discussed in consideration of subgrain rotation or twinning taking place near the original grain boundaries. Particular attention is also paid to the role of continuous dynamic recrystallization (CDRX) at both higher and lower temperatures

Analysis of Effective and Internal Cyclic Stress Components in the Inconel Superalloy Fatigued at Elevated Temperature

Czech Academy of Sciences Publication Activity Database

Šmíd, Miroslav; Petrenec, Martin; Polák, Jaroslav; Obrtlík, Karel; Chlupová, Alice

2011-01-01

Roč. 278, 4 July (2011), s. 393-398 ISSN 1022-6680. [European Symposium on Superalloys and their Application. Wildbad Kreuth, 25.5.2010-28.5.2010] R&D Projects: GA ČR GA106/08/1631 Institutional research plan: CEZ:AV0Z20410507 Keywords : low cycle fatigue * superalloys * high temperature * hysteresis loop * effective and internal stresses Subject RIV: JL - Materials Fatigue, Friction Mechanics; JL - Materials Fatigue, Friction Mechanics (UFM-A)

Advanced Scale Bridging Microstructure Analysis of Single Crystal Ni-Base Superalloys

Czech Academy of Sciences Publication Activity Database

Parsa, A. B.; Wollgramm, P.; Buck, H.; Somsen, C.; Kostka, A.; Povstugar, I.; Choi, P.-P.; Raabe, D.; Dlouhý, Antonín; Müller, J.; Spiecker, E.; Demtroder, K.; Schreuer, J.; Neuking, K.; Eggeler, G.

2015-01-01

Roč. 17, č. 2 (2015), s. 216-230 ISSN 1438-1656 Institutional support: RVO:68081723 Keywords : High temperature materials * Nickel based superalloys * EPMA * HRTEM Subject RIV: JG - Metallurgy Impact factor: 1.817, year: 2015

A continuum model for the anisotropic creep of single crystal nickel-based superalloys

International Nuclear Information System (INIS)

Prasad, Sharat C.; Rajagopal, K.R.; Rao, I.J.

2006-01-01

In this paper, we extend the constitutive theory developed by Prasad et al. [Prasad SC, Rao IJ, Rajagopal KR. A continuum model for the creep of single crystal nickel-base superalloys. Acta Mater 2005;53(3):669-79], to describe the creep anisotropy associated with crystallographic orientation in single crystal nickel-based superalloys. The constitutive theory is cast within a general thermodynamic framework that has been developed to describe the response of materials capable of existing in multiple stress free configurations ('natural configurations'). Central to the theory is the prescription of the forms for the stored energy and rate of dissipation functions. The stored energy reflects the fact that the elastic response exhibits cubic symmetry. The model takes into account the fact that the symmetry of single crystals does not change with inelastic deformation. The rate of dissipation function is also chosen to be anisotropic, in that it reflects invariance to transformations that belong to the cubic symmetry group. The model is used to simulate uniaxial creep of single crystal nickel-based superalloy CMSX-4 for loading along the , and orientations. The predictions of the theory agree well with the experimental data

Effect of transient liquid phase (TLP) bonding on the ductility of a Ni-base single crystal superalloy in a stress rupture test

International Nuclear Information System (INIS)

Liu, J.D.; Jin, T.; Zhao, N.R.; Wang, Z.H.; Sun, X.F.; Guan, H.R.; Hu, Z.Q.

2008-01-01

A Ni-base single crystal superalloy was transient liquid phase (TLP) bonded using a Ni-Cr-B amorphous foil at 1230 deg. C for 8 h. Stress rupture tests of the TLP joint and a matrix sample were carried out at 982 deg. C/248 MPa and 1010 deg. C/248 MPa. The microstructures and fracture surfaces were studied using scanning electron microscopy (SEM). Transmission electron microscopy (TEM) investigations were performed after creep rupture testing to examine the deformation substructures. The results show that the stress rupture ductility of TLP joints is significantly decreased compared to the matrix sample. This reduction of the ductility of TLP joints can be attributed to solid solution strengthening by boron atoms, subgrain boundaries formed in the bonding zone and the concentration of creep cavities formed during the last stage of the stress rupture test

Microstructural and mechanical characterization of injection molded 718 superalloy powders

Energy Technology Data Exchange (ETDEWEB)

Özgün, Özgür [Bingol University, Faculty of Engineering and Architecture, Mechanical Eng. Dep., 12000 Bingol (Turkey); Gülsoy, H. Özkan, E-mail: ogulsoy@marmara.edu.tr [Marmara University, Technology Faculty, Metallurgy and Materials Eng. Dep., 34722 Istanbul (Turkey); Yılmaz, Ramazan [Sakarya University, Technology Faculty, Metallurgy and Materials Eng. Dep., 54187 Sakarya (Turkey); Fındık, Fehim [Sakarya University, Technology Faculty, Metallurgy and Materials Eng. Dep., 54187 Sakarya (Turkey) and International University of Sarajevo, Faculty of Engineering and Natural Sciences, Department of Mechanical Engineering, 71000 Sarajevo, Bosnia and Herzegovina (Bosnia and Herzegowina)

2013-11-05

Highlights: •Microstructural and mechanical properties of injection molded Nickel 718 superalloy were studied. •The maximum sintered density achieved this study was 97.3% at 1290 °C for 3 hours. •Tensile strength of 1022 MPa and elongation of 5.3% were achieved for sintered-heat treated samples. -- Abstract: This study concerns with the determination of optimum production parameters for injection molding 718 superalloy parts. And at the same time, microstructural and mechanical characterization of these produced parts was also carried out. At the initial stage, 718 superalloy powders were mixed with a multi-component binder system for preparing feedstock. Then the prepared feedstock was granulated and shaped by injection molding. Following this operation, the shaped samples were subjected to the debinding process. These samples were sintered at different temperatures for various times. Samples sintered under the condition that gave way to the highest relative density (3 h at 1290 °C) were solution treated and aged respectively. Sintered, solution treated and aged samples were separately subjected to microstructural and mechanical characterization. Microstructural characterization operations such as X-ray diffraction, optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and elemental analysis showed that using polymeric binder system led to plentiful carbide precipitates to be occurred in the injection molded samples. It is also observed that the volume fractions of the intermetallic phases (γ′ and γ″) obtained by aging treatment were decreased due to the plentiful carbide precipitation in the samples. Mechanical characterization was performed by hardness measurements and tensile tests.

Multiscale modelling of single crystal superalloys for gas turbine blades

NARCIS (Netherlands)

Tinga, T.

2009-01-01

Gas turbines are extensively used for power generation and for the propulsion of aircraft and vessels. Their most severely loaded parts, the turbine rotor blades, are manufactured from single crystal nickel-base superalloys. The superior high temperature behaviour of these materials is attributed to

Oxide-assisted crack growth in hold-time low-cycle-fatigue of single-crystal superalloys

Directory of Open Access Journals (Sweden)

Suzuki Akane

2014-01-01

Full Text Available Compressive hold-time low-cycle fatigue is one of the important damage modes in Ni-based superalloy hot-gas path components. In strain controlled LCF, the compressive hold typically degrades fatigue life significantly due to creep relaxation and the resultant generation of tensile stress upon returning to zero strain. Crack initiation typically occurs on the surface, and therefore, the cracks are covered with layers of oxides. Recent finite element modeling based on experimental observations has indicated that the in-plane compressive stress in the alumina layer formed on the surface of the bond coat assists rumpling and, eventually, leads to initiation of cracks. The stress in the oxide layer continues to assist crack extension by pushing the alumina layer along the crack front during the compressive hold. In-situ measurements of the growth strains of alumina were performed using high energy synchrotron X-rays at Argonne National Lab. Specimens of single-crystal superalloys with and without aluminide coatings were statically pre-oxidized to form a layer of alumina at 1093 and 982 ∘C. For the in-situ synchrotron measurements, the specimens were heated up to the pre-oxidation temperatures with a heater. The alumina layers on both bare and coated specimens show compressive in-plane strains at both temperatures. The oxide strains on the superalloys showed dependency on temperature; on the other hand, the oxide strains in the aluminide coatings were insensitive to temperature. The magnitude of the compressive strains was larger on the superalloys than the ones on the aluminide coatings.

Cyclic Oxidation and Hot Corrosion of NiCrY-Coated Disk Superalloys

Science.gov (United States)

Gabb, Timothy P.; Miller, Robert A.; Sudbrack, Chantal K.; Draper, Susan L.; Nesbitt, James A.; Rogers, Richard B.; Telesman, Ignacy; Ngo, Vanda; Healy, Jonathan

2016-01-01

Powder metallurgy disk superalloys have been designed for higher engine operating temperatures through improvement of their strength and creep resistance. Yet, increasing disk application temperatures to 704 degrees Centigrade and higher could enhance oxidation and activate hot corrosion in harmful environments. Protective coatings could be necessary to mitigate such attack. Cylindrical coated specimens of disk superalloys LSHR and ME3 were subjected to thermal cycling to produce cyclic oxidation in air at a maximum temperature of 760 degrees Centigrade. The effects of substrate roughness and coating thickness on coating integrity after cyclic oxidation were considered. Selected coated samples that had cyclic oxidation were then subjected to accelerated hot corrosion tests. This cyclic oxidation did not impair the coating's resistance to subsequent hot corrosion pitting attack.

Cyclic Oxidation and Hot Corrosion of NiCrY-Coated Disk Superalloy

Science.gov (United States)

Gabb, Tim; Miller, R. A.; Sudbrack, C. K.; Draper, S. L.; Nesbitt, J.; Telesman, J.; Ngo, V.; Healy, J.

2015-01-01

Powder metallurgy disk superalloys have been designed for higher engine operating temperatures through improvement of their strength and creep resistance. Yet, increasing disk application temperatures to 704 C and higher could enhance oxidation and activate hot corrosion in harmful environments. Protective coatings could be necessary to mitigate such attack. Cylindrical coated specimens of disk superalloys LSHR and ME3 were subjected to thermal cycling to produce cyclic oxidation in air at a maximum temperature of 760 C. The effects of substrate roughness and coating thickness on coating integrity after cyclic oxidation were considered. Selected coated samples that had cyclic oxidation were then subjected to accelerated hot corrosion tests. The effects of this cyclic oxidation on resistance to subsequent hot corrosion attack were examined.

Thermodynamic assessment of liquid composition change during solidification and its effect on freckle formation in superalloys

International Nuclear Information System (INIS)

Long Zhengdong; Liu Xingbo; Yang Wanhong; Chang, K.-M.; Barbero, Ever

2004-01-01

The solidification macrosegregation, i.e. freckle, becomes more and more concerned with ever increasing demand for the large ingot size of superalloys. The evaluation of freckle formation is very difficult because of the less understanding of freckle formation mechanism and complex solidification behaviors of multi-component superalloys. The macrostructure of typical Nb-bearing and Ti-bearing superalloys in horizontally directional solidification and vacuum arc remelting (VAR) ingots were investigated to clarify the freckle formation mechanism. The thermodynamic approach was proposed to simulate the solidification behaviors. The relative Ra numbers, a reliable criterion, of freckle formation for some alloys were obtained based on the results of thermodynamic calculations. This thermodynamic approach was evaluated through comparison of the calculations from semi-experimental results. The Ra numbers obtained by thermodynamic approach are in good agreement with the ingot size capability of the industry melting shops, which is limited mainly by freckle defects

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...

Refractory metal superalloys: Design of yttrium aluminum garnet passivating niobium alloys

Science.gov (United States)

Bryan, David

A systems-based approach, integrating computational modeling with experimental techniques to approach engineering problems in a time and cost efficient manner, was employed to design a Nb-based refractory superalloy for use at 1300°C. Ashby-type selection criteria for both thermodynamic and kinetic parameters were employed to identify a suitable protective oxide for Nb alloys. Yttrium aluminum garnet (YAG) was selected as the most promising candidate for its excellent combination of desirable properties. The alloy microstructural concept was based upon the gamma - gamma' nickel-based superalloys in which the multifunctional gamma' phase serves as both a creep strengthening dispersion and a source of reactive elements for oxide passivation. Candidate ternary Pd-Y-Al and Pt-Y-Al compounds were fabricated and characterized by XRD and DTA. Of the intermetallics studied, only PtYAl had a high enough melting point (1580°C) for use in an alloy operating at 1300°C. The alloy matrix design was based upon Wahl's extension of Wagner's criterion for protective oxidation, requiring a reduction of the product N ODO/DAl by 5 orders of magnitude relative to binary Nb-Al. A thermodynamic and kinetic analysis identified elements with large oxygen affinities as the most beneficial for reducing the magnitude of the quantity NOD O. Construction of a combined thermodynamic and mobility database identified increased Al solubility as the best approach for increasing D Al. Utilizing the thermodynamic and mobility databases, obtained from a combination of model alloys, oxidation experiments, and first principles calculations, theoretical designs predicted the large changes in solubility and transport parameters were achievable. Several prototype alloys were then fabricated and evaluated via oxidation tests at both 1300°C and 1100°C. YAG formation was demonstrated as part of multicomponent oxide scales in the alloys that exhibited the greatest reduction in oxidation rates. The oxidation

Effects of Temperature and Pressure of Hot Isostatic Pressing on the Grain Structure of Powder Metallurgy Superalloy.

Science.gov (United States)

Tan, Liming; He, Guoai; Liu, Feng; Li, Yunping; Jiang, Liang

2018-02-24

The microstructure with homogeneously distributed grains and less prior particle boundary (PPB) precipitates is always desired for powder metallurgy superalloys after hot isostatic pressing (HIPping). In this work, we studied the effects of HIPping parameters, temperature and pressure on the grain structure in PM superalloy FGH96, by means of scanning electron microscope (SEM), electron backscatter diffraction (EBSD), transmission electron microscope (TEM) and Time-of-flight secondary ion spectrometry (ToF-SIMS). It was found that temperature and pressure played different roles in controlling PPB precipitation and grain structure during HIPping, the tendency of grain coarsening under high temperature could be inhibited by increasing HIPping pressure which facilitates the recrystallization. In general, relatively high temperature and pressure of HIPping were preferred to obtain an as-HIPped superalloy FGH96 with diminished PPB precipitation and homogeneously refined grains.

Improvement of creep-rupture properties by serrated grain boundaries in high-tungsten cobalt-base superalloys

International Nuclear Information System (INIS)

Tanaka, Manabu

1993-01-01

The improvement of creep-rupture properties by serrated grain boundaries was investigated using cobalt-base superalloys containing about 14 to 20 wt.% tungsten at 1089 and 1311 K. Serrated grain boundaries improved both the rupture life and the ductility, especially under lower stresses at 1089 K. The increase in rupture life was larger in the alloys containing a larger amount of W. Ductile grain boundary fracture surfaces, which involved dimple patterns and grain boundary ledges, were observed in the specimens with serrated grain boundaries whereas brittle grain boundary facets were observed in the specimens with normal straight grain boundaries ruptured at 1089 K. The strengthening by serrated grain boundaries was also effective at 1311 K, but there was little difference in rupture life between the specimens with serrated grain boundaries and those with straight grain boundaries under lower stresses, since serrated grain boundaries developed also in the specimens with straight grain boundaries according to grain boundary precipitates forming during creep at 1311 K. The increase in W content of the alloys led to the increase in rupture life of the specimens with serrated grain boundaries at 1089 and 1311 K. (orig.) [de

Effect of laser shock on tensile deformation behavior of a single crystal nickel-base superalloy

International Nuclear Information System (INIS)

Lu, G.X.; Liu, J.D.; Qiao, H.C.; Zhou, Y.Z.; Jin, T.; Zhao, J.B.; Sun, X.F.; Hu, Z.Q.

2017-01-01

This investigation focused on the tensile deformation behavior of a single crystal nickel-base superalloy, both in virgin condition and after laser shock processing (LSP) with varied technology parameters. Nanoindention tests were carried out on the sectioned specimens after LSP treatment to characterize the surface strengthening effect. Stress strain curves of tensile specimens were analyzed, and microstructural observations of the fracture surface and the longitudinal cross-sections of ruptured specimens were performed via scanning electron microscope (SEM), in an effort to clarify the fracture mechanisms. The results show that a surface hardening layer with the thickness of about 0.3–0.6 mm was gained by the experimental alloys after LSP treatment, but the formation of surface hardening layer had not affected the yield strength. Furthermore, fundamental differences in the plastic responses at different temperatures due to LSP treatment had been discovered. At 700 °C, the slip deformation was held back when it extended to the surface hardening layer and the ensuing slip steps improved the plasticity; however, at 1000 °C, surface hardening layer hindered the macro necking, which resulted in the relatively lower plasticity.

Effect of laser shock on tensile deformation behavior of a single crystal nickel-base superalloy

Energy Technology Data Exchange (ETDEWEB)

Lu, G.X. [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049 (China); Liu, J.D., E-mail: jdliu@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Qiao, H.C. [Shenyang Institute of Automation, Chinese Academy of Sciences, 114 Nanta Road, Shenyang 110016 (China); Zhou, Y.Z. [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Jin, T., E-mail: tjin@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Zhao, J.B. [Shenyang Institute of Automation, Chinese Academy of Sciences, 114 Nanta Road, Shenyang 110016 (China); Sun, X.F.; Hu, Z.Q. [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

2017-02-16

This investigation focused on the tensile deformation behavior of a single crystal nickel-base superalloy, both in virgin condition and after laser shock processing (LSP) with varied technology parameters. Nanoindention tests were carried out on the sectioned specimens after LSP treatment to characterize the surface strengthening effect. Stress strain curves of tensile specimens were analyzed, and microstructural observations of the fracture surface and the longitudinal cross-sections of ruptured specimens were performed via scanning electron microscope (SEM), in an effort to clarify the fracture mechanisms. The results show that a surface hardening layer with the thickness of about 0.3–0.6 mm was gained by the experimental alloys after LSP treatment, but the formation of surface hardening layer had not affected the yield strength. Furthermore, fundamental differences in the plastic responses at different temperatures due to LSP treatment had been discovered. At 700 °C, the slip deformation was held back when it extended to the surface hardening layer and the ensuing slip steps improved the plasticity; however, at 1000 °C, surface hardening layer hindered the macro necking, which resulted in the relatively lower plasticity.

On post-weld heat treatment cracking in tig welded superalloy ATI 718Plus

Science.gov (United States)

Asala, G.; Ojo, O. A.

The susceptibility of heat affected zone (HAZ) to cracking in Tungsten Inert Gas (TIG) welded Allvac 718Plus superalloy during post-weld heat treatment (PWHT) was studied. Contrary to the previously reported case of low heat input electron beam welded Allvac 718Plus, where HAZ cracking occurred during PWHT, the TIG welded alloy is crack-free after PWHT, notwithstanding the presence of similar micro-constituents that caused cracking in the low input weld. Accordingly, the formation of brittle HAZ intergranular micro-constituents may not be a sufficient factor to determine cracking propensity, the extent of heat input during welding may be another major factor that influences HAZ cracking during PWHT of the aerospace superalloy Allvac 718Plus.

Kink structures induced in nickel-based single crystal superalloys by high-Z element migration

Energy Technology Data Exchange (ETDEWEB)

Sun, Fei; Zhang, Jianxin [Key Laboratory for Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Mao, Shengcheng [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China); Jiang, Ying [Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Feng, Qiang [National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Shen, Zhenju; Li, Jixue; Zhang, Ze [Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Han, Xiaodong [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China)

2015-01-05

Highlights: • Innovative kink structures generate at the γ/γ′ interfaces in the crept superalloy. • Clusters of heavy elements congregate at the apex of the kinks. • Dislocation core absorbs hexagonal structural high-Z elements. - Abstract: Here, we investigate a new type of kink structure that is found at γ/γ′ interfaces in nickel-based single crystal superalloys. We studied these structures at the atomic and elemental level using aberration corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The core of the dislocation absorbs high-Z elements (i.e., Co and Re) that adopt hexagonal arrangements, and it extrudes elements (i.e., Ni and Al) that adopt face centered cubic (fcc) structures. High-Z elements (i.e., Ta and W) and Cr, which is a low-Z element, are stabilized in body centered cubic (bcc) arrangements; Cr tends to behave like Re. High-Z elements, which migrate and adopt a hexagonal structure, induce kink formation at γ/γ′ interfaces. This process must be analyzed to fully understand the kinetics and dynamics of creep in nickel-based single crystal superalloys.

Grain Boundary Engineering the Mechanical Properties of Allvac 718Plus(Trademark) Superalloy

Science.gov (United States)

Gabb, Timothy P.; Telesman, Jack; Garg, Anita; Lin, Peter; Provenzano, virgil; Heard, Robert; Miller, Herbert M.

2010-01-01

Grain Boundary Engineering can enhance the population of structurally-ordered "low S" Coincidence Site Lattice (CSL) grain boundaries in the microstructure. In some alloys, these "special" grain boundaries have been reported to improve overall resistance to corrosion, oxidation, and creep resistance. Such improvements could be quite beneficial for superalloys, especially in conditions which encourage damage and cracking at grain boundaries. Therefore, the effects of GBE processing on high-temperature mechanical properties of the cast and wrought superalloy Allvac 718Plus (Allvac ATI) were screened. Bar sections were subjected to varied GBE processing, and then consistently heat treated, machined, and tested at 650 C. Creep, tensile stress relaxation, and dwell fatigue crack growth tests were performed. The influences of GBE processing on microstructure, mechanical properties, and associated failure modes are discussed.

Substoichiometric extraction of phosphorus

International Nuclear Information System (INIS)

Shigematsu, T.; Kudo, K.

1981-01-01

A study of the substoichiometric extraction of phosphorus is described. Phosphorus was extracted in the form of ternary compounds such as ammonium phosphomolybdate, 8-hydroxyquinolinium phosphomolybdate, tetraphenylarsonium phosphomolybdate and tri-n-octylamine phosphomolybdate. Consequently, phosphorus was extracted substoichiometrically by the addition of a substoichiometric amount of molybdenum for the four phosphomolybdate compounds. On the other hand, phosphorus could be separated substoichiometrically with a substoichiometric amount of tetraphenylarsonium chloride or tri-n-octylamine. Stoichiometric ratios of these ternary compounds obtained substoichiometrically were 1:12:3 for phosphorus, molybdenum and organic reagent. The applicability of these compounds to phosphorus determination is also discussed. (author)

Nanosize boride particles in heat-treated nickel base superalloys

International Nuclear Information System (INIS)

Zhang, H.R.; Ojo, O.A.; Chaturvedi, M.C.

2008-01-01

Grain boundary microconstituents in aged nickel-based superalloys were studied by transmission electron microscopy techniques. A nanosized M 5 B 3 boride phase, possibly formed by intergranular solute desegregation-induced precipitation, was positively identified. The presence of these intergranular nanoborides provides reasonable clarification of a previously reported reduction of grain boundary liquation temperature during the weld heat affected zone thermal cycle

Use of Phosphorus Isotopes for Improving Phosphorus Management in Agricultural Systems

International Nuclear Information System (INIS)

2016-10-01

Phosphorus is an essential element in plant, human and animal nutrition. Soils with low levels of phosphorus are widespread in many regions of the world, and the deficiency limits plant growth and reduces crop production and food quality. This publication provides comprehensive and up to date information on several topics related to phosphorus in soil–plant systems, in agricultural systems and in the environment. It presents the theoretical background as well as practical information on how to use nuclear and radioisotope tracer techniques in both laboratory and greenhouse experiments to assess soil phosphorus forms and plant-available soil phosphorus pools, and to understand the cycling processes in soil–plant systems. The publication focuses on practical applications of radiotracer techniques and can serve as resource material for research projects on improving sustainable phosphorus management in agricultural systems and as practical guidance on the use of phosphate isotopes in soil–plant research

The effects of Ta on the stress rupture properties and microstructural stability of a novel Ni-base superalloy for land-based high temperature applications

International Nuclear Information System (INIS)

Zheng, Liang; Zhang, Guoqing; Lee, Tung L.; Gorley, Michael J.; Wang, Yue; Xiao, Chengbo; Li, Zhou

2014-01-01

Highlights: • An equiaxed superalloy has high rupture life equivalent to single crystal alloy DD3. • Low Cr and high W superalloys possess good microstructrual stability at 850–1100 °C. • Tantalum promotes, strengthens and stabilizes the eutectic γ′ and MC carbides. • Excessive Ta leads to form harmful abnormal primary α and plate-like M 6 C phases. • Proper Ta can improve the stress rupture life at intermediate and high temperatures. - Abstract: A novel polycrystalline Ni-base superalloy was developed for land-based high temperature applications, such as isothermal forging dies and industrial gas turbines. The alloy possessed surprisingly high stress rupture life of 52 h at 1100 °C/118 MPa which is comparable to the first generation single crystal (SC) superalloy and exhibited good microstructural stability. The effects of Ta addition on the phase change, stress rupture properties and microstructural stability of the alloy were investigated. The results indicated that Ta is a γ′-former and promotes the formation of eutectic γ′. The alloys with ∼7 vol.% eutectic γ′ possess higher stress rupture life at 1100 °C/118 MPa than the alloys with higher ∼20 vol.% eutectic. However, ∼20 vol.% excessive eutectic phases will enhance the stress rupture life at intermediate temperature of 760 °C for 686 MPa but weaken high temperature stress rupture properties. The (Al + Ta) content over 14.4 at.% led to the formation of large amounts of eutectic γ′ and exceeded the solubility of W and Mo in the residue liquid pool, which then promoted the precipitation of primary α-(W,Mo) and M 6 C phases. Tantalum was also found as a strong MC carbides forming element. The order of ability to form monocarbide decreased from NbC to TaC to TiC. 6Al–0Ta (wt.%) alloys possessed good microstructural stability with no harmful topologically close-packed (TCP) phases being observed after thermal exposure at 850 °C/3000 h, 900 °C/1000 h. Only trace amounts of

Oxidation behavior of HVOF sprayed Ni-5Al coatings deposited on Ni- and Fe-based superalloys under cyclic condition

International Nuclear Information System (INIS)

Mahesh, R.A.; Jayaganthan, R.; Prakash, S.

2008-01-01

Ni-5Al coating was obtained on three superalloy substrates viz. Superni 76, Superni 750 and Superfer 800 using high velocity oxy-fuel (HVOF) spray process. Oxidation studies were carried out on both bare and coated superalloy substrates in air at 900 deg. C for 100 cycles. The weight change was measured at the end of each cycle and observed that the weight gain was high in Superni 750 alloy when compared to Superni 76 and Superfer 800. A nearly parabolic oxidation behavior was observed for Ni-5Al coated Superni 750 and Superfer 800 alloys but a Ni-5Al coated Superni 76 substrate showed a slight deviation. The scale was analysed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) and electron probe microanalysis (EPMA). The coating increased the oxidation resistance for all the alloy substrates at 900 deg. C. Among the three-coated superalloys, Superfer 800 substrate has shown the best resistance to oxidation. The protective nature of the Ni-5Al coated superalloys was due to the formation of protective oxide scales such as NiO, Al 2 O 3 and Cr 2 O 3

Response to Discussion of "Investigation of Oxide Bifilms in Investment Cast Superalloy IN100 Part I and II"

Science.gov (United States)

Kaplan, M. A.; Fuchs, G. E.

2017-10-01

In his most recent letter (Campbell in Met Trans A, 2017), Professor Campbell provides additional comments on Kaplan and Fuchs papers "Oxides Bifilms in Superalloy: IN100, Parts I and II (Met Trans A 47A:2346-2361, 2016; Met Trans A 47A:2362-2375, 2016) and on their response to his initial comments (Met Trans A 47A:3806-3809, 2016). In this recent submission, Campbell provides some very interesting thoughts on why bifilms were not observed by Kaplan and Fuchs and creates a new theory for the formation of defects referred to as bifilms. However, Campbell again provides no evidence to substantiate the presence of bifilms in Ni-base superalloys or his newly theorized mechanism. The vast majority of Campbell's comments are based solely on the re-interpretation of the photomicrographs and the data reported in the literature, including those presented by Kaplan and Fuchs (Met Trans A 47A:2346-2361, 2016; Met Trans A 47A:2362-2375, 2016). Campbell claims that bifilms are present throughout Ni-base superalloys, even though no one else has reported the presence of bifilms in Ni-base superalloys. In re-interpreting the data and images, Campbell ignores the extensive surface characterization results reported by Kaplan and Fuchs (Met Trans A 47A:2346-2361, 2016; Met Trans A 47A:2362-2375, 2016) that clearly indicate that there are no oxide films or bifilms on the fracture surfaces examined. Please note that this discussion of Campbell's most recent letter will be limited to Ni-base superalloys, since that is the subject of the research reported by Kaplan and Fuchs.

phosphorus sorption capacity as a guide for phosphorus availability

African Journals Online (AJOL)

Prof. Adipala Ekwamu

drained, light yellowish brown, loamy sand ... Dongola 2 Akked series: Deep, dark grayish brown, clay ... energy. Statistical analysis. Data collected were statistically analysed using ANOVA of MStatc ... phosphorus sorbed versus phosphorus.

Creep mechanisms of U720Li disc superalloy at intermediate temperature

International Nuclear Information System (INIS)

Yuan, Y.; Gu, Y.F.; Cui, C.Y.; Osada, T.; Tetsui, T.; Yokokawa, T.; Harada, H.

2011-01-01

Highlights: → Crept microstructures of U720Li at 725 deg. C/630 MPa have been investigated by TEM. → Orowan looping process combining dislocation slip and climb and partial dislocations shearing precipitates were the main creep mechanisms. → Grain boundary sliding occurred at last creep stage. → Three methods were suggested to improve the creep property at relatively high temperature. - Abstract: The microstructures of U720Li disc superalloy have been investigated by transmission electron microscopy (TEM) before and after creep test at 725 deg. C/630 MPa. The evolution of the crept microstructures was marked as three different stages (I, II and III) corresponding to gradually increased strain 0.1%, 5% and 27%, respectively. At stage I, dislocations bypassed secondary γ' via Orowan loops. At stage II, partial dislocations started to shear secondary γ', leaving stacking fault (SF) behind and microtwins formed in part of grains. At stage III, grain boundary sliding occurred due to very large strain and increased effective stress. The results indicated that the creep mechanisms of U720Li at 725 deg. C/630 MPa evolved with gradually increased strain. Orowan looping process combining dislocation slip and climb and partial dislocations shearing precipitates were the main creep mechanisms. It is suggested that decreasing the interparticle spacing of secondary γ', strengthening secondary γ' and decreasing stacking fault energy (SFE) of γ matrix may be effective methods to improve the creep property at relatively higher temperatures.

CLASSICAL AREAS OF PHENOMENOLOGY: First-principles calculations for the elastic properties of Ni-base model superalloys: Ni/Ni3Al multilayers

Science.gov (United States)

Wang, Yun-Jiang; Wang, Chong-Yu

2009-10-01

A model system consisting of Ni[001](100)/Ni3Al[001](100) multi-layers are studied using the density functional theory in order to explore the elastic properties of single crystal Ni-based superalloys. Simulation results are consistent with the experimental observation that rafted Ni-base superalloys virtually possess a cubic symmetry. The convergence of the elastic properties with respect to the thickness of the multilayers are tested by a series of multilayers from 2γ'+2γ to 10γ'+10γ atomic layers. The elastic properties are found to vary little with the increase of the multilayer's thickness. A Ni/Ni3Al multilayer with 10γ'+10γ atomic layers (3.54 nm) can be used to simulate the mechanical properties of Ni-base model superalloys. Our calculated elastic constants, bulk modulus, orientation-dependent shear modulus and Young's modulus, as well as the Zener anisotropy factor are all compatible with the measured results of Ni-base model superalloys R1 and the advanced commercial superalloys TMS-26, CMSX-4 at a low temperature. The mechanical properties as a function of the γ' phase volume fraction are calculated by varying the proportion of the γ and γ' phase in the multilayers. Besides, the mechanical properties of two-phase Ni/Ni3Al multilayer can be well predicted by the Voigt-Reuss-Hill rule of mixtures.

Refractory porcelain enamel passive-thermal-control coating for high-temperature superalloys

Science.gov (United States)

Levin, H.; Auker, B. H.; Gardos, M. N.

1973-01-01

Study was conducted to match thermal expansion coefficients thereby preventing enamels from cracking. Report discusses various enamel coatings that are applied to two different high-temperature superalloys. Study may be of interest to manufacturers of chemical equipment, furnaces, and metal components intended for high-temperature applications.

Microstrain evolution during creep of a high volume fraction superalloy

Energy Technology Data Exchange (ETDEWEB)

Ma, S. [Materials Department, New Mexico Tech, Socorro, NM 87801 (United States); Brown, D. [Los Alamos National Laboratory, Los Alamos, NM (United States); Bourke, M.A.M. [Los Alamos National Laboratory, Los Alamos, NM (United States); Daymond, M.R. [Rutherford Appleton Laboratory, ISIS Facility, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Majumdar, B.S. [Materials Department, New Mexico Tech, Socorro, NM 87801 (United States)]. E-mail: majumdar@nmt.edu

2005-06-15

The creep of superalloys containing a high volume fraction of {gamma}' phase is significantly influenced by initial misfit and by the evolution of internal stresses. An in situ neutron diffraction technique was used to monitor elastic microstrains in a polycrystalline superalloy, CM247 LC. The misfit was nearly zero at room temperature and it increased to -0.17% at 900 deg. C. These values are rationalized in terms of thermal mismatch using an eigenstrain formulation and a simple formula is derived to relate the thermal mismatch to the misfit strain. During creep at 425 MPa at 900 deg. C, the material exhibited primarily tertiary behavior. For grains with [0 0 1] axis close to the loading direction, the elastic microstrain in the loading direction increased with creep time for the {gamma}' phase, whereas the opposite occurred for the {gamma} phase. These results are explained in terms of constrained deformation in the narrow {gamma} channels and by an interface dislocation buildup. TEM analysis of the crept microstructure provides evidence of the interface dislocation network.

Castability of Traditionally Wrought Ni-Based Superalloys for USC Steam Turbines

Energy Technology Data Exchange (ETDEWEB)

Jablonski, P D; Cowen, C J; Hawk, J A; Evens, N; Maziasz, P

2011-02-27

The high temperature components within conventional coal fired power plants are manufactured from ferritic/martensitic steels. In order to reduce greenhouse gas emissions the efficiency of pulverized coal steam power plants must be increased. The proposed steam temperature in the Advanced Ultra Supercritical (A-USC) power plant is high enough (760°C) that ferritic/martensitic steels will not work due to temperature limitations of this class of materials; thus Ni-based superalloys are being considered. The full size castings are quite substantial: ~4in thick, several feet in diameter and weigh 5-10,000lb each half. Experimental castings were quite a bit smaller, but section size was retained and cooling rate controlled in order to produce relevant microstructures. A multi-step homogenization heat treatment was developed in order to better deploy the alloy constituents. The castability of two traditionally wrought Ni-based superalloys to which minor alloy adjustments have been made in order to improve foundry performance is further explored.

Phase Transformations in Nickel base Superalloy Inconel 718 during Cyclic Loading at High Temperature

Directory of Open Access Journals (Sweden)

Michal Jambor

2017-06-01

Full Text Available Nickel base superalloys are hi-tech materials intended for high temperature applications. This property owns a complex microstructure formed by matrix of Ni and variety of precipitates. The type, form and the amount of these phases significantly affect the resulting properties of these alloys. At sufficiently long exposure to high temperatures, the transformation phase can occur, which can lead to degradation of properties of these alloys. A cyclic plastic deformation can accelerate these changes, and they could occur at significantly lower temperatures or in shorter time of exposure. The aim of this study is to describe phase transformation, which can occur by a cyclic plastic deformation at high temperatures in nickel base superalloy Inconel 718.

A new method to predict the metadynamic recrystallization behavior in a typical nickel-based superalloy

International Nuclear Information System (INIS)

Lin, Y.C.; Chen, Xiao-Min; Chen, Ming-Song; Wen, Dong-Xu; Zhou, Ying; He, Dao-Guang

2016-01-01

The metadynamic recrystallization (MDRX) behaviors of a typical nickel-based superalloy are investigated by two-pass hot compression tests and four conventional stress-based conventional approaches (offset stress method, back-extrapolation stress method, peak stress method, and mean stress method). It is found that the conventional stress-based methods are not suitable to evaluate the MDRX softening fractions for the studied superalloy. Therefore, a new approach, 'maximum stress method', is proposed to evaluate the MDRX softening fraction. Based on the proposed method, the effects of deformation temperature, strain rate, initial average grain size, and interpass time on MDRX behaviors are discussed in detail. Results show that MDRX softening fraction is sensitive to deformation parameters. The MDRX softening fraction rapidly increases with the increase of deformation temperature, strain rate, and interpass time. The MDRX softening fraction in the coarse-grain material is lower than that in the fine-grain material. Moreover, the observed microstructures indicate that the initial coarse grains can be effectively refined by MDRX. Based on the experimental results, the kinetics equations are established and validated to describe the MDRX behaviors of the studied superalloy. (orig.)

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

Comparison of Thermodynamic Predictions and Experimental Observations on B Additions in Powder-Processed Ni-Based Superalloys Containing Elevated Concentrations of Nb

Science.gov (United States)

Antonov, Stoichko; Huo, Jiajie; Feng, Qiang; Isheim, Dieter; Seidman, David N.; Sun, Eugene; Tin, Sammy

2018-03-01

Boron additions to Ni-based superalloys are considered to be beneficial to the creep properties of the alloy, as boron has often been reported to increase grain boundary cohesion, increase ductility, and promote the formation of stable boride phases. Despite the importance, it is not well understood whether these improvements are associated with the presence of elemental boron or stable borides along the grain boundaries. In this investigation, two experimental powder-processed Ni-based superalloys containing elevated levels of Nb were found to exhibit increased solubility for B in the γ matrix when compared to similar commercial Ni-based superalloys. This resulted in an overall lower B concentration at grain boundaries that suppressed boride formation. As the predictive capability of CALPHAD database models for Ni-based superalloys have improved over the years, some discrepancies may still persist around compositionally heterogeneous features such as grain boundaries. Improved quantification of the characteristic partitioning of B as a function of the bulk alloy composition is required for understanding and predicting the stability of borides.

Power metallurgy approaches to high temperature components for gas turbine engines

Science.gov (United States)

Probst, H. B.

1974-01-01

Work conducted by NASA and NASA contractors on prealloyed superalloy powders and materials strengthened by oxide dispersion is reviewed. Fabrication, tensile strength, superplasticity, grain growth control, stress rupture life, and grain-size and dispersion-level effects are covered. Distinct strength advantages of powder metallurgy superalloys over conventional wrought alloys are noted.

Failure mechanisms of superhard materials when cutting superalloys

International Nuclear Information System (INIS)

Focke, A.E.; Westermann, F.E.; Ermi, A.; Yavelak, J.; Hoch, M.

1975-01-01

The present research studies the reasons for the failure of tungsten carbide tools while cutting superalloys. There is a continuous layer of the superalloy in the bottom of the crater which from time to time is torn away locally, taking tungsten carbide crystal with it. Under recommended cutting conditions a plateau (unworn cutting surface) separates the crater from the cutting edge of the tool when cutting AISI 4340. This plateau is totally absent in all cutting of Inconel 718, even in short, two-minute tests. The crater intersects the cutting edge--only a thin wedge of carbide is left which either breaks off or deforms and wears very rapidly. Temperature measurements carried out by use of an infrared detector aimed on the corner of the tungsten carbide indicate at recommended speeds a sharp rise of the temperature at the beginning of the cutting operation, then a steady-state very slow increase as the cutting continues, and finally just before tool failure a very rapid increase in the temperature again. Scanning and replica electron microscopy through the crater and flank face shows that both under the crater and in the back of the cutting edge a fairly deep layer of ''disturbed metal'' exists in which the tungsten carbide grains are much smaller and have much more rounded edges than in the original material. 10 figures, 4 tables

Correlation Between the Microstructural Defects and Residual Stress in a Single Crystal Nickel-Based Superalloy During Different Creep Stages

Science.gov (United States)

Mo, Fangjie; Wu, Erdong; Zhang, Changsheng; Wang, Hong; Zhong, Zhengye; Zhang, Jian; Chen, Bo; Hofmann, Michael; Gan, Weimin; Sun, Guangai

2018-03-01

The present work attempts to reveal the correlation between the microstructural defects and residual stress in the single crystal nickel-based superalloy, both of which play the significant role on properties and performance. Neutron diffraction was employed to investigate the microstructural defects and residual stresses in a single crystal (SC) nickel-based superalloy, which was subjected to creeping under 220 MPa and 1000 °C for different times. The measured superlattice and fundamental lattice reflections confirm that the mismatch and tetragonal distortions with c/a > 1 exist in the SC superalloy. At the initially unstrained state, there exists the angular distortion between γ and γ' phases with small triaxial compressive stresses, ensuring the structural stability of the superalloy. After creeping, the tetragonal distortion for the γ phase is larger than that for the γ' phase. With increasing the creeping time, the mismatch between γ and γ' phases increases to the maximum, then decreases gradually and finally remains unchanged. The macroscopic residual stress shows a similar behavior with the mismatch, indicating the correlation between them. Based on the model of shear and dislocations, the evolution of microstructural defects and residual stress are reasonably explained. The effect of shear is dominant at the primary creep stage, which greatly enlarges the mismatch and the residual stress. The dislocations weaken the effect of shear for the further creep stage, resulting in the decrease of the mismatch and relaxation of the residual stress. Those findings add some helpful understanding into the microstructure-performance relationship in the SC nickel-based superalloy, which might provide the insight to materials design and applications.

Organic chemistry of elemental phosphorus

International Nuclear Information System (INIS)

Milyukov, V A; Budnikova, Yulia H; Sinyashin, Oleg G

2005-01-01

The principal achievements and the modern trends in the development of the chemistry of elemental phosphorus are analysed, described systematically and generalised. The possibilities and advantages of the preparation of organophosphorus compounds directly from white phosphorus are demonstrated. Attention is focused on the activation and transformation of elemental phosphorus in the coordination sphere of transition metal complexes. The mechanisms of the reactions of white phosphorus with nucleophilic and electrophilic reagents are discussed. Electrochemical approaches to the synthesis of organic phosphorus derivatives based on white phosphorus are considered.

High-temperature and low-stress creep anisotropy of single-crystal superalloys

Czech Academy of Sciences Publication Activity Database

Jacome, L. A.; Nortershauser, P.; Heyer, J. K.; Lahni, A.; Frenzel, J.; Dlouhý, Antonín; Somsen, C.; Eggeler, G.

2013-01-01

Roč. 61, č. 8 (2013), s. 2926-2943 ISSN 1359-6454 R&D Projects: GA ČR(CZ) GA202/09/2073 Institutional support: RVO:68081723 Keywords : superalloy single crystals * creep anisotropy * rafting * dislocations * deformation mechanisms Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.940, year: 2013

Liquation Cracking in the Heat-Affected Zone of IN738 Superalloy Weld

Directory of Open Access Journals (Sweden)

Kai-Cheng Chen

2018-05-01

Full Text Available The main scope of this study investigated the occurrence of liquation cracking in the heat-affected zone (HAZ of IN738 superalloy weld, IN738 is widely used in gas turbine blades in land-based power plants. Microstructural examinations showed considerable amounts of γ’ uniformly precipitated in the γ matrix. Electron probe microanalysis (EPMA maps showed the γ-γ’ colonies were rich in Al and Ti, but lean in other alloy elements. Moreover, the metal carbides (MC, fine borides (M3B2 and M5B3, η-Ni3Ti, σ (Cr-Co and lamellar Ni7Zr2 intermetallic compounds could be found at the interdendritic boundaries. The fracture morphologies and the corresponding EPMA maps confirmed that the liquation cracking in the HAZ of the IN738 superalloy weld resulted from the presence of complex microconstituents at the interdendritic boundaries.

The effects of Re addition to the nanostructure of a Ni-Cr-Al model superalloy

International Nuclear Information System (INIS)

Yoon, K.E.; Seidman, D.N.; Noebe, R.D.

2004-01-01

Full text: The refractory elements, such as W, Mo, Ta, and Re, have been at the center of focus since the late 1970s for the development of single-crystal turbine-blades, and they have improved significantly the high-temperature properties of Ni-based superalloys. The optimum mechanical properties and operating temperature of single-crystal blades are achieved by increasing the total amounts of refractory elements. In spite of the improvement of mechanical properties of Ni-based superalloys utilizing the addition of refractory elements, their effects on the microstructure of superalloys are mostly unidentified at the subnano- to nanoscale. Rhenium (2 at.%) was added to a model ternary Ni-8.5 at.% Cr-10 at.% Al superalloy to study its effects on the temporal evolution. The temporal evolution of γ' (L1 2 ) precipitates in a Ni-Cr-AI-Re FCC alloy, aged at 1073 K from 0.25 to 264 h, is investigated by transmission-electron and three-dimensional atom-probe (3DAP) microscopies. The coarsening kinetics of γ' precipitates is investigated by measuring the mean radius, number density of precipitates and matrix supersaturation, and compared with Umantsev-Olson's (UO) coarsening theory for multicomponent alloys. The coarsening experiments do not agree with the time dependencies prediction of UO theory. The cluster-diffusion-coagulation mechanism is involved in coarsening, as well as evaporation-condenzation mechanism, and is suggested to generate discrepancy between the experiments and theory. The addition of Re reduces the lattices parameter misfit between the matrix and precipitates. Therefore, unlike other Ni-based superalloys, this Ni-Cr-AI-Re alloy does not undergo the sphere-to-cube morphological transition and maintains the spheroidal morphology of the γ' precipitates for extended aging times. In addition, the γ' precipitates do not align along [100] direction, even at the longest aging time of 264 h. Contrary to a commercial superalloy Rene N6, significant Re

The Effectiveness of a NiCrY-Coating on a Powder Metallurgy Disk Superalloy

Science.gov (United States)

Gabb, Timothy P.; Miller, Robert A.; Nesbitt, James A.; Draper, Susan L.; Rogers, Richard B.; Telesman, Jack

2018-01-01

Protective ductile coatings could be necessary to mitigate oxidation and corrosion attack on superalloy disks in some turbine engine applications. However, the effects of coatings on fatigue life of the disk during service are an important concern. The objective of this study was to investigate how such a coating could perform after varied post-coating processing. Cylindrical gage fatigue specimens of powder metallurgy-processed disk superalloy LSHR were coated with a NiCrY coating, shot peened, preparation treated, exposed, and then subjected to fatigue at high temperature. The effects of varied shot peening, preparation treatment, and exposures on fatigue life with and without the coating were compared. Each of these variables and several of their interactions significantly influenced fatigue life.

Sargasso Sea phosphorus biogeochemistry: an important role for dissolved organic phosphorus (DOP

Directory of Open Access Journals (Sweden)

M. W. Lomas

2010-02-01

Full Text Available Inorganic phosphorus (SRP concentrations in the subtropical North Atlantic are some of the lowest in the global ocean and have been hypothesized to constrain primary production. Based upon data from several transect cruises in this region, it has been hypothesized that dissolved organic phosphorus (DOP supports a significant fraction of primary production in the subtropical North Atlantic. In this study, a time-series of phosphorus biogeochemistry is presented for the Bermuda Atlantic Time-series Study site, including rates of phosphorus export. Most parameters have a seasonal pattern, although year-over-year variability in the seasonal pattern is substantial, likely due to differences in external forcing. Suspended particulate phosphorus exhibits a seasonal maximum during the spring bloom, despite the absence of a seasonal peak in SRP. However, DOP concentrations are at an annual maximum prior to the winter/spring bloom and decline over the course of the spring bloom while whole community alkaline phosphatase activities are highest. As a result of DOP bioavailability, the growth of particles during the spring bloom occurs in Redfield proportions, though particles exported from the euphotic zone show rapid and significant remineralization of phosphorus within the first 50 m below the euphotic zone. Based upon DOP data from transect cruises in this region, the southward cross gyral flux of DOP is estimated to support ~25% of annual primary production and ~100% of phosphorus export. These estimates are consistent with other research in the subtropical North Atlantic and reinforce the hypothesis that while the subtropics may be phosphorus stressed (a physiological response to low inorganic phosphorus, utilization of the DOP pool allows production and accumulation of microbial biomass at Redfield proportions.

Interdiffusion between Ni-based superalloy and MCrAlY coating

DEFF Research Database (Denmark)

Dahl, Kristian Vinter; Hald, John; Horsewell, Andy

2006-01-01

Interdiffusion at the interface between a Co-36.5Ni-17.5Cr-8Al-0.5Y, MCrAlY coating and the underlying IN738 superalloy was studied in a large matrix of specimens isothermally heat treated for up to 12,000 hours at temperatures 875oC, 925oC or 950oC. Modelled results using the finite difference...

Creep deformation and microstructural examination of a prior thermally exposed nickel base superalloy

Czech Academy of Sciences Publication Activity Database

Zrník, J.; Strunz, Pavel; Vrchovinský, V.; Muránsky, O.; Horňák, P.; Wiedenmann, A.

2004-01-01

Roč. 274 (2004), s. 925-930 ISSN 1013-9826 R&D Projects: GA AV ČR KSK1010104 Keywords : superalloy * thermal exposition * creep Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.278, year: 2004

Phosphorus use efficiency of maize: an investigation using radiotracer phosphorus (32P)

International Nuclear Information System (INIS)

Meena, S.

2017-01-01

A better understanding on the nutrient uptake and utilization by plants is essential for developing better nutrient efficient cultivars suited for optimal production. Precise information on the PUE of crops and P dynamics can be obtained with the help of radiotracer technique. To study the phosphorus acquisition and phosphorus use efficiency of added sources in maize using 32 P, a pot culture experiment was conducted in a medium P soil (21.26 kg ha -1 ). The treatments were P as Single Superphosphate, Enriched FYM with Single Superphosphate (EFYM), DAP, Nutriseed pack (SSP), Nutriseed pack (DAP). The above treatments were applied along with phosphobacteria. Totally there were ten treatments replicated four times. Phosphorus sources were tagged with 32 P (obtained as 32 P in orthophosphoric medium from the Board of Radiation and Isotope Technology) and applied as per the treatments. Radioactive 32 P in the grain and stover sample was determined using Liquid Scintillation Counter (Perkin Elmer Tricarb 2810 R). Using the data, per cent phosphorus derived from fertilizer (%Pdff), per cent phosphorus derived from soil (%Pdfs), Phosphorus Use Efficiency (PUE) and A value were determined. Application of Phosphorus (SSP, DAP, enriched FYM with SSP, Nutriseed pack (SSP) and Nutriseed pack (DAP)) along with PB increased the per cent phosphorus derived from fertilizer (% Pdff), P uptake from fertilizer and PUE. The highest PUE of 25.38 was recorded in the treatment where enriched FYM with SSP was applied along with PB. (author)

High Temperature Degradation of Powder-processed Ni-based Superalloy

Directory of Open Access Journals (Sweden)

Natália Luptáková

2015-05-01

Full Text Available The aim of present work is to study the high temperature degradation of the powder-processed polycrystalline superalloy Ni-15Cr-18Co-4Al-3.5Ti-5Mo. This superalloy has been applied as material for grips of a creep machine. The material was exposed at 1100 °C for about 10 days at 10 MPa stress. During the creep test occurred unacceptable creep deformation of grips as well as severe surface oxidation with scales peeling off. Three types of the microstructure were observed in the studied alloy: (i unexposed state; (ii heat treated (annealing - 10 min/1200 °C and (iii after using as a part of the equipment of the creep machine during the creep test. It is shown that the microstructure degradation resulting from the revealed γ´ phase fcc Ni3(Al,Ti particles preferentially created at the grain boundaries of the samples after performing creep tests affects mechanical properties of the alloy and represents a significant contribution to all degradation processes affecting performance and service life of the creep machine grips. Based on investigation and obtained results, the given material is not recommended to be used for grips of creep machine at temperatures above 1000 °C.

Computational Design and Prototype Evaluation of Aluminide-Strengthened Ferritic Superalloys for Power-Generating Turbine Applications up to 1,033 K

Energy Technology Data Exchange (ETDEWEB)

Peter Liaw; Gautam Ghosh; Mark Asta; Morris Fine; Chain Liu

2010-04-30

The objective of the proposed research is to utilize modern computational tools, integrated with focused experiments, to design innovative ferritic NiAl-strengthened superalloys for fossil-energy applications at temperatures up to 1,033 K. Specifically, the computational alloy design aims toward (1) a steady-state creep rate of approximately 3 x 10{sup -11} s{sup -1} at a temperature of 1,033 K and a stress level of 35 MPa, (2) a ductility of 10% at room temperature, and (3) good oxidation and corrosion resistance at 1,033 K. The research yielded many outstanding research results, including (1) impurity-diffusion coefficients in {alpha} Fe have been calculated by first principles for a variety of solute species; (2) the precipitates were characterized by the transmission-electron microscopy (TEM) and analytical-electron microscopy (AEM), and the elemental partitioning has been determined; (3) a bending ductility of more than 5% has been achieved in the unrolled materials; and (4) optimal compositions with minimal secondary creep rates at 973 K have been determined. Impurity diffusivities in {alpha} Fe have been calculated within the formalisms of a harmonic transition-state theory and Le Claire nine-frequency model for vacancy-mediated diffusion. Calculated diffusion coefficients for Mo and W impurities are comparable to or larger than that for Fe self-diffusion. Calculated activation energies for Ta and Hf impurities suggest that these solutes should display impurity-diffusion coefficients larger than that for self-diffusion in the body-centered cubic Fe. Preliminary mechanical-property studies identified the alloy Fe-6.5Al-10Ni-10Cr-3.4Mo-0.25Zr-0.005B (FBB-8) in weight percent (wt.%) for detailed investigations. This alloy shows precipitation of NiAl particles with an average diameter of 130 nm. In conjunction with the computational alloy design, selected experiments are performed to investigate the effect of the Al content on the ductility and creep of

Anisotropic constitutive equations for the viscoplastic behaviour of the single crystal superalloy CMSX-4

International Nuclear Information System (INIS)

Fleury, G.; Schubert, F.

1997-09-01

Nickel-base superalloy blades of the first rotor stage in a gas turbine have to withstand extremely severe thermomechanical loading conditions. Single crystal blades exhibit a highly anisotropic deformation behaviour and are subjected to triaxial stress fields induced by complex cooling systems. Consequently the prediction of their deformation behaviour requires constitutive equations based on multiaxial formulations. The microstructural evolution of γ/γ' superalloys during the service time modifies the material properties and has therefore to be taken into account in the constitutive equations. For the modelling of the anisotropic, viscoplastic behaviour of single crystal blades taking into account the evolution of the microstructure, a microstructure-dependent, orthotropic Hills potential, whose anisotropy coefficients are connected to the edge length of the γ'-particles, is applied. The prediction was validated by investigating the deformation behaviour of the superalloy CMSX-4 in the range of temperatures [750 C-950 C]. If the shape of γ'-particles remain cubic, for example, in creep testing at low temperatures (up to about 850 C), the microstructure-dependent potential leads to the cubic version of the Hills potential. The prediction is in good agreement with creep results for left angle 001 right angle - and left angle 111 right angle - orientated specimens but overestimates the creep resistance of left angle 011 right angle - orientated specimens. (orig.)

Molecular dynamics simulation of edge dislocation piled at cuboidal precipitate in Ni-based superalloy

International Nuclear Information System (INIS)

Yashiro, Kisaragi; Naito, Masato; Tomita, Yoshihiro

2003-01-01

In order to clarify the fundamental mechanism of dislocations in the γ/γ' microstructure of Ni-based superalloy, three molecular dynamics simulations are conducted on the behavior of edge dislocations nucleated from a free surface and proceeding in the pure Ni matrix (γ) toward cuboidal Ni 3 Al precipitates (γ') under shear force. One involves dislocations near the apices of two precipitates adjoining each other with the distance of 0.04 μm, as large as the width of the γ channel in real superalloys. Others simulate dislocations piled at the precipitates as well, however, the scale of the microstructure is smaller than that in real superalloys by one order of magnitude, and one of them have precipitates with atomistically sharp edge. Dislocations are pinned at precipitates and bowed-out in the γ channel, then they begin to penetrate into the precipitate at the edge in both the real-scale and smaller microstructures when the precipitates have blunt edges. On the other hand, an edge dislocation splits into a superpartial in the γ' precipitate and a misfit screw dislocation bridging between two adjacent precipitates at the atomistically sharp edge of γ' precipitates. It is also observed that two superpartials glide in the precipitate as a superdislocation with anti-phase boundary (APB), of which the width is evaluated to be about 4 nm. (author)

Abnormal flow behavior and necklace microstructure of powder metallurgy superalloys with previous particle boundaries (PPBs)

Energy Technology Data Exchange (ETDEWEB)

Ning, Yongquan, E-mail: luckyning@nwpu.edu.cn [School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Zhou, Cong; Liang, Houquan [School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Fu, M.W., E-mail: mmmwfu@polyu.edu.hk [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)

2016-01-15

Powder metallurgy (P/M) has been introduced as an innovative process to manufacture high performance components with fine, homogenous and segregation-free microstructure. Unfortunately, previous particle boundary (PPB) precipitated during the powder metallurgy process. Since undesirable PPB is detrimental to mechanical properties, hot extrusion or/and isothermal forging are needed. In present research, isothermal compression tests were conducted on P/M FGH4096 superalloys with typical PPBs. Abnormal flow behavior during high-speed deformation has been quantitatively investigated. Caused by the competition mechanism between work-hardening and dynamic-softening, abnormal flow behaves typical four stages (viz., work-hardening, stable, softening and steady). Microstructure observation for hardening or/and softening mechanism has been investigated. Meanwhile, necklace microstructure was observed by scanning electron microscope, and the grain fraction analysis was performed by using electron backscatter diffraction. Transmission electron microscopy was used for characterizing the boundary structure. Necklace microstructural mechanism for processing P/M superalloys has been developed, and the dynamic recrystallization model has also been conducted. Bulge–corrugation model is the primary nucleation mechanism for P/M superalloys with PPBs. When PPB is entirely covered with new grains, necklace microstructure has formed. Bulge–corrugation mechanism can repeatedly take place in the following necklace DRX.

Cyclic Oxidation and Hot Corrosion Behavior of Nickel-Iron-Based Superalloy

Science.gov (United States)

Chellaganesh, D.; Adam Khan, M.; Winowlin Jappes, J. T.; Sathiyanarayanan, S.

2018-01-01

The high temperature oxidation and hot corrosion behavior of nickel-iron-based superalloy are studied at 900 ° and 1000 °C. The significant role of alloying elements with respect to the exposed medium is studied in detail. The mass change per unit area was catastrophic for the samples exposed at 1000 °C and gradual increase in mass change was observed at 900 °C for both the environments. The exposed samples were further investigated with SEM, EDS and XRD analysis to study the metallurgical characteristics. The surface morphology has expressed the in situ nature of the alloy and its affinity toward the environment. The EDS and XRD analysis has evidently proved the presence of protective oxides formation on prolonged exposure at elevated temperature. The predominant oxide formed during the exposure at high temperature has a major contribution toward the protection of the samples. The nickel-iron-based superalloy is less prone to oxidation and hot corrosion when compared to the existing alloy in gas turbine engine simulating marine environment.

The effects of ruthenium on the phase stability of fourth generation Ni-base single crystal superalloys

International Nuclear Information System (INIS)

Sato, Atsushi; Harada, Hiroshi; Yokokawa, Tadaharu; Murakumo, Takao; Koizumi, Yutaka; Kobayashi, Toshiharu; Imai, Hachiro

2006-01-01

The formation of topologically close-packed (TCP) phases in nickel-base single crystal superalloys causes considerable degradation of the mechanical properties. It has recently been found that platinum-group metals can be effective in controlling the precipitation of such phases, and this extent of precipitation control requires further investigation. This study compares Ru-containing and non-Ru-containing single crystal superalloys. Scanning electron microscopy microstructural observations showed that the rate of TCP phase precipitations decreased through Ru addition. Transmission electron microscopy microstructural observations showed that the P phase, one of the TCP phases, was eliminated through the addition of Ru. The occurrence of this phenomenon will be discussed

Towards global phosphorus security: A systems framework for phosphorus recovery and reuse options

NARCIS (Netherlands)

Cordell, D.; Rosemarin, A.; Schroder, J.J.; Smit, A.L.

2011-01-01

Human intervention in the global phosphorus cycle has mobilised nearly half a billion tonnes of the element from phosphate rock into the hydrosphere over the past half century. The resultant water pollution concerns have been the main driver for sustainable phosphorus use (including phosphorus

Misorientation related microstructure at the grain boundary in a nickel-based single crystal superalloy

International Nuclear Information System (INIS)

Huang, Ming; Zhuo, Longchao; Liu, Zhanli; Lu, Xiaogang; Shi, Zhenxue; Li, Jiarong; Zhu, Jing

2015-01-01

The mechanical properties of nickel-based single crystal superalloys deteriorate with increasing misorientation, thus the finished product rate of the casting of single crystal turbine airfoils may be reduced due to the formation of grain boundaries especially when the misorientation angle exceeds to some extent. To this day, evolution of the microstructures at the grain boundaries with misorientation and the relationship between the microstructures and the mechanical properties are still unclear. In this work a detailed characterization of the misorientation related microstructure at the grain boundary in DD6 single crystal superalloy has been carried out using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques; the elemental distribution at the grain boundaries has been analyzed by energy dispersive (EDS) X-ray mapping; and the effect of precipitation of μ phases at the grain boundary on the mechanical property has been evaluated by finite element calculation. It is shown that the proportion of γ phase at the grain boundaries decreases, while the proportion of γ′ phase at the grain boundaries increases with increasing misorientation; the μ phase is precipitated at the grain boundaries when the misorientation angle exceeds about 10° and thus it could lead to a dramatic deterioration of the mechanical properties, as well as that the enrichment of Re and W gradually disappears as the misorientation angle increases. All these factors may result in the degradation of the mechanical properties at the grain boundaries as the misorientation increases. Furthermore, the finite element calculation confirms that precipitation of μ phases at the grain boundary is responsible for the significant deterioration of the mechanical properties when the misorientation exceeds about 10°. This work provides a physical imaging of the microstructure for understanding the relationship between the mechanical properties and the misorientation

Effect of supplemented fungal phytase on performance and phosphorus availability by phosphorus-depleted juvenile rainbow trout (Oncorhynchus mykiss), and on the magnitude and composition of phosphorus waste output

DEFF Research Database (Denmark)

Dalsgaard, Anne Johanne Tang; Schøn Ekmann, K.; Pedersen, Per Bovbjerg

2009-01-01

The effect of a supplemental fungal phytase on performance and phosphorus availability by juvenile rainbow trout fed diets with a high inclusion of plant based protein and on the magnitude and composition of the waste phosphorus production was tested in a 2 × 3 factorial design at a temperature....../suspended phosphorus waste output from fish fed the phytase supplemented diet containing 0.71% available phosphorus, suggesting that the phosphorus requirement was reached at this phosphorus level. Consistent with this, there was a substantial increase in the dissolved/suspended phosphorus waste output from fish fed...... the phytase supplemented diet containing 0.81% available phosphorus, suggesting that the phosphorus requirement was exceeded in this group. This study demonstrated that phytase supplementation will be advantageous to the fish and the environment if supplemented to low-phosphorus diets containing a large share...

Rapid solidification and dynamic compaction of Ni-base superalloy powders

Science.gov (United States)

Field, R. D.; Hales, S. J.; Powers, W. O.; Fraser, H. L.

1984-01-01

A Ni-base superalloy containing 13Al-9Mo-2Ta (in at. percent) has been characterized in both the rapidly solidified condition and after dynamic compaction. Dynamically compacted specimens were examined in the as-compacted condition and observations related to current theories of interparticle bonding. In addition, the recrystallization behavior of the compacted material at relatively low temperature (about 0.5-0.75 Tm) was investigated.

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

III. Quantitative aspects of phosphorus excretionin ruminants

OpenAIRE

Bravo , David; Sauvant , Daniel; Bogaert , Catherine; Meschy , François

2003-01-01

International audience; Ruminant phosphorus excretion and metabolism were studied through a database. Faecal endogenous phosphorus is the main pathway of phosphorus excretion and averages 0.85 of total faecal phosphorus. The remaining 0.15 is unabsorbed dietary phosphorus. Faecal endogenous phosphorus is mainly unabsorbed phosphorus, with saliva being the major source, and is correlated to factors influencing saliva secretion (DM intake, physical dietary characteristics and dietary phosphorus...

Low heat input welding of nickel superalloy GTD-111 with Inconel 625 filler metal

Energy Technology Data Exchange (ETDEWEB)

Athiroj, Athittaya; Wangyao, Panyawat; Hartung, Fritz; Lothongkum, Gobboon [Chulalongkorn Univ., Bangkok (Thailand). Dept. of Metallurgical Engineering

2018-03-01

GTD-111 precipitation-strengthened nickel-based superalloy is widely used in blades of gas turbine engines which operate at high temperature and in a hot localized corrosion atmosphere. After long-term exposure to high temperature, γ' precipitate is known to exhibit catastrophic changes in size and distribution which cause deterioration of its properties and failure of the component. In this study, a damaged blade removed from a land-based gas turbine generator was subjected to nonpre-heat-treated GTAW and laser welding repair with various welding powers in the range of 135 to 295 J x mm{sup -1}, followed by post-weld heat treatment (PWHT) at 1473 K for 7200 s and strain aging at 1118 K for 86 400 s. Results show no significant relationship between welding powers, size and area fraction of the γ' precipitate in the fcc γ matrix in both GTAW and laser-welded specimens. The final γ' precipitate size and distribution depend mainly on PWHT parameters as γ' precipitates in all GTAW and laser welded specimens showed similar size and area fraction independently of the heat input from welding. Unmixed zones are observed in all laser welding specimens which may cause preferential weld corrosion during service. Microcrack occurrence due to welding and PWHT processes is also discussed.

Phosphorus blood test

Science.gov (United States)

... page: //medlineplus.gov/ency/article/003478.htm Phosphorus blood test To use the sharing features on this page, please enable JavaScript. The phosphorus blood test measures the amount of phosphate in the blood. ...

STUDY OF THE MECHANICAL PROPERTIES OF INCONEL 718 SUPERALLOY AFTER HOT TENSILE TESTS

Directory of Open Access Journals (Sweden)

Tarcila Sugahara

2014-10-01

Full Text Available This research work investigated some important mechanical properties of Inconel 718 superalloy using hot tensile tests like conventional yield strength to 0.2% strain (σe , ultimate strength (σr , and specific elongation (εu . Samples were strained to failure at temperatures of 600°C, 650°C, 700°C, 750°C, 800°C and 850°C and strain rate of 0.5 mm/min (2 × 10–4 s–1 according to ASTM E-8. The results showed higher values σe of yield strength at 700°C, this anomalous behavior can be attributed to the presence of hardening precipitates as observed in the TTT diagram of superalloy Inconel 718. Examination of the sample’s surfaces tensile fracture showed that with increasing temperature test the actuating mechanism changes from intergranular fracture to coalescence of the microcavities.

Atomic force microscopy imaging to measure precipitate volume fraction in nickel-based superalloys

International Nuclear Information System (INIS)

Bourhettar, A.; Troyon, M.; Hazotte, A.

1995-01-01

In nickel-based superalloys, quantitative analysis of scanning electron microscopy images fails in providing accurate microstructural data, whereas more efficient techniques are very time-consuming. As an alternative approach, the authors propose to perform quantitative analysis of atomic force microscopy images of polished/etched surfaces (quantitative microprofilometry). This permits the measurement of microstructural parameters and the depth of etching, which is the main source of measurement bias. Thus, nonbiased estimations can be obtained by extrapolation of the measurements up to zero etching depth. In this article, the authors used this approach to estimate the volume fraction of γ' precipitates in a nickel-based superalloy single crystal. Atomic force microscopy images of samples etched for different times show definition, homogeneity, and contrast high enough to perform image analysis. The result after extrapolation is in very good agreement with volume fraction values available from published reports

Screening crops for efficient phosphorus acquisition in a low phosphorus soil using radiotracer technique

International Nuclear Information System (INIS)

Meena, S.; Malarvizhi, P.; Rajeswari, R.

2017-01-01

Deficiency of phosphorus (P) is the major limitation to agricultural production. Identification of cultivars with greater capacity to grow in soils having low P availability (phosphorus efficiency) will help in P management in a sustainable way. Green house experiment with maize (CO 6) and cotton (MCU 13) as test crops with four levels of phosphorus (0, 3.75, 7.50 and 15 mg P kg -1 soil) was conducted in a P deficient soil (7.2 kg ha -1 ) to study the phosphorus acquisition characteristics and to select efficient crop using 32 P radiotracer technique. Carrier free 32 P obtained as orthophosphoric acid in dilute hydrochloric acid medium from the Board of Radiation and Isotope Technology, Mumbai was used for labeling the soil @ 3200 kBq pot -1 . After 60 days the crops were harvested and the radioactivity was measured in the plant samples using Liquid scintillation counter (PerkinElmer - Tricarb 2810 TR). Different values of specific radioactivity and Isotopically Exchangeable Phosphorus for maize and cotton indicated that chemically different pools of soil P were utilized and maize accessing a larger pool than cotton. Maize having recorded high Phosphorus Use Efficiency, Phosphorus Efficiency and low Phosphorus Stress Factor values, it is a better choice for P deficient soils. Higher Phosphorus Acquisition Efficiency of maize (59 %) than cotton (48%) can be related to the ability of maize to take up P from insoluble inorganic P forms. (author)

Ledges and grooves at γ/γ′ interfaces of single crystal superalloys

Czech Academy of Sciences Publication Activity Database

Parsa, A. B.; Wollgramm, P.; Buck, H.; Kostka, A.; Somsen, C.; Dlouhý, Antonín; Eggeler, G.

2015-01-01

Roč. 90, MAY (2015), s. 105-117 ISSN 1359-6454 R&D Projects: GA ČR(CZ) GA14-22834S Institutional support: RVO:68081723 Keywords : Ni-base single crystal superalloys * γ/γ′ interfaces * Interface dislocations * Rafting * Grooves Subject RIV: JG - Metallurgy Impact factor: 5.058, year: 2015

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.

Mechanical characterization of superalloys for space reactors

International Nuclear Information System (INIS)

Duchesne, J.

1989-01-01

The aim of this work is the selection of structural materials that can be used in the temperature range 600-900 0 C for a gas cooled space reactor producing electricity. Superalloys fit best the temperature range required. Five nickel base alloys are chosen for their good mechanical behaviour: HAYNES 230, HASTELLOY S, HASTELLOY X, HASTELLOY XR and PYRAD 38D. Metallography, tensile and hardness tests are realized. Sample contraction is evidenced for some creep tests, under low stress: 20MPa at 800 0 C, on HAYNES 230 and HASTELLOY X, probably related to the structural evolution of these materials corresponding to a decrease of the crystal parameter [fr

Extension of an anisotropic creep model to general high temperature deformation of a single crystal superalloy

International Nuclear Information System (INIS)

Pan, L.M.; Ghosh, R.N.; McLean, M.

1993-01-01

A physics based model has been developed that accounts for the principal features of anisotropic creep deformation of single crystal superalloys. The present paper extends this model to simulate other types of high temperature deformation under strain controlled test conditions, such as stress relaxation and tension tests at constant strain rate in single crystals subject to axial loading along an arbitrary crystal direction. The approach is applied to the SRR99 single crystal superalloy where a model parameter database is available, determined via analysis of a database of constant stress creep curves. A software package has been generated to simulate the deformation behaviour under complex stress-strain conditions taking into account anisotropic elasticity. (orig.)

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.

Few-layer black phosphorus nanoparticles.

Science.gov (United States)

Sofer, Zdenek; Bouša, Daniel; Luxa, Jan; Mazanek, Vlastimil; Pumera, Martin

2016-01-28

Herein, black phosphorus quantum dots and nanoparticles of a few layer thickness were prepared and characterized using STEM, AFM, dynamic light scattering, X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy and photoluminescence. Impact electrochemistry of the induvidual black phosphorus nanoparticles allows their size determination. The centrifugation of colloidal black phosphorus nanoparticles allowed separation of quantum dots with sizes up to 15 nm. These black phosphorus nanoparticles exhibit a large band gap and are expected to find a wide range of applications from semiconductors to biomolecule tags. The use of black phosphorus nanoparticles for vapour sensing was successfully demonstrated.

Microstructure of the Nickel-Base Superalloy CMSX-4 Fabricated by Selective Electron Beam Melting

Science.gov (United States)

Ramsperger, Markus; Singer, Robert F.; Körner, Carolin

2016-03-01

Powder bed-based additive manufacturing (AM) processes are characterized by very high-temperature gradients and solidification rates. These conditions lead to microstructures orders of magnitude smaller than in conventional casting processes. Especially in the field of high performance alloys, like nickel-base superalloys, this opens new opportunities for homogenization and alloy development. Nevertheless, the high susceptibility to cracking of precipitation-hardenable superalloys is a challenge for AM. In this study, electron beam-based AM is used to fabricate samples from gas-atomized pre-alloyed CMSX-4 powder. The influence of the processing strategy on crack formation is investigated. The samples are characterized by optical and SEM microscopy and analyzed by microprobe analysis. Differential scanning calorimetry is used to demonstrate the effect of the fine microstructure on characteristic temperatures. In addition, in situ heat treatment effects are investigated.

Dietary phosphorus acutely impairs endothelial function.

Science.gov (United States)

Shuto, Emi; Taketani, Yutaka; Tanaka, Rieko; Harada, Nagakatsu; Isshiki, Masashi; Sato, Minako; Nashiki, Kunitaka; Amo, Kikuko; Yamamoto, Hironori; Higashi, Yukihito; Nakaya, Yutaka; Takeda, Eiji

2009-07-01

Excessive dietary phosphorus may increase cardiovascular risk in healthy individuals as well as in patients with chronic kidney disease, but the mechanisms underlying this risk are not completely understood. To determine whether postprandial hyperphosphatemia may promote endothelial dysfunction, we investigated the acute effect of phosphorus loading on endothelial function in vitro and in vivo. Exposing bovine aortic endothelial cells to a phosphorus load increased production of reactive oxygen species, which depended on phosphorus influx via sodium-dependent phosphate transporters, and decreased nitric oxide production via inhibitory phosphorylation of endothelial nitric oxide synthase. Phosphorus loading inhibited endothelium-dependent vasodilation of rat aortic rings. In 11 healthy men, we alternately served meals containing 400 mg or 1200 mg of phosphorus in a double-blind crossover study and measured flow-mediated dilation of the brachial artery before and 2 h after the meals. The high dietary phosphorus load increased serum phosphorus at 2 h and significantly decreased flow-mediated dilation. Flow-mediated dilation correlated inversely with serum phosphorus. Taken together, these findings suggest that endothelial dysfunction mediated by acute postprandial hyperphosphatemia may contribute to the relationship between serum phosphorus level and the risk for cardiovascular morbidity and mortality.

Effect of phosphorus stress on Microcystis aeruginosa growth and phosphorus uptake.

Directory of Open Access Journals (Sweden)

Sajeela Ghaffar

Full Text Available This study was designed to advance understanding of phosphorus regulation of Microcystis aeruginosa growth, phosphorus uptake and storage in changing phosphorus (P conditions as would occur in lakes. We hypothesized that Microcystis growth and nutrient uptake would fit classic models by Monod, Droop, and Michaelis-Menten in these changing conditions. Microcystis grown in luxury nutrient concentrations was transferred to treatments with phosphorus concentrations ranging from 0-256 μg P∙L-1 and luxury nitrogen. Dissolved phosphorus concentration, cell phosphorus quota, P uptake rate and cell densities were measured at day 3 and 6. Results showed little relationship to predicted models. Microcystis growth was asymptotically related to P treatment from day 0-3, fitting Monod model well, but negatively related to P treatment and cell quota from day 3-6. From day 0-3, cell quota was negatively related to P treatments at <2 μg∙L-1, but increased slightly at higher P. Cell quota decreased greatly in low P treatments from day 3-6, which may have enabled high growths in low P treatments. P uptake was positively and linearly related to P treatment during both periods. Negative uptake rates and increases in measured culture phosphorus concentrations to 5 μg∙L-1 in the lowest P treatments indicated P leaked from cells into culture medium. This leakage during early stages of the experiment may have been sufficient to stimulate metabolism and use of intracellular P stores in low P treatments for rapid growth. Our study shows P regulation of Microcystis growth can be complex as a result of changing P concentrations, and this complexity may be important for modeling Microcystis for nutrient and ecosystem management.

Solidification behaviors of a single-crystal superalloy under lateral constraints

International Nuclear Information System (INIS)

Zhuangqi Hu; Huaming Wang

1993-01-01

The effect of lateral constraints ahead of solidification interface on the solidification behaviors of a newly developed hot corrosion resistant single-crystal nickel-base superalloy was investigated under commercial single-crystal production conditions. The lateral constraints or section variations ahead of solidification front were found to have drastic influences both on the modes of solidification and the profiles of solute segregation. As lateral constraints were imposed ahead of the directionally solidifying interface, the solidification microstructure of the single-crystal superalloy changed suddenly, through a γ/γ' eutectic-free zone which is characterized by an extremely-fine and highly-developed dendrite network, from the original well-branched dendritic structure to a fine cellular-dendrite or regular cell structure, accompanying which the primary arm spacing, the severity of segregation and the amount of microporosity decreased remarkably. The newly formed cellular dendrite or cell structure transforms always gradually to the initial coarse dendrite structure as the lateral constraint is finally released whether gradually or sharply. Moreover, an abnormal porosity zone was readily observed in the initial section beneath and away from the eutectic-free zone. The solidification microstructural changes were attributed to the drastic dynamical changes in local solidification cooling conditions and in momentum transport during solidification due to the presence of lateral constraint

Novel casting processes for single-crystal turbine blades of superalloys

Science.gov (United States)

Ma, Dexin

2018-03-01

This paper presents a brief review of the current casting techniques for single-crystal (SC) blades, as well as an analysis of the solidification process in complex turbine blades. A series of novel casting methods based on the Bridgman process were presented to illustrate the development in the production of SC blades from superalloys. The grain continuator and the heat conductor techniques were developed to remove geometry-related grain defects. In these techniques, the heat barrier that hinders lateral SC growth from the blade airfoil into the extremities of the platform is minimized. The parallel heating and cooling system was developed to achieve symmetric thermal conditions for SC solidification in blade clusters, thus considerably decreasing the negative shadow effect and its related defects in the current Bridgman process. The dipping and heaving technique, in which thinshell molds are utilized, was developed to enable the establishment of a high temperature gradient for SC growth and the freckle-free solidification of superalloy castings. Moreover, by applying the targeted cooling and heating technique, a novel concept for the three-dimensional and precise control of SC growth, a proper thermal arrangement may be dynamically established for the microscopic control of SC growth in the critical areas of large industrial gas turbine blades.

Dendritic coarsening of γ' phase in a directionally solidified superalloy during 24,000 h of exposure at 1173 K

International Nuclear Information System (INIS)

Li, H.; Wang, L.; Lou, L.H.

2010-01-01

Dendritic coarsening of γ' was investigated in a directionally solidified Ni-base superalloy during exposure at 1173 K for 24,000 h. Chemical homogeneity along different directions and residual internal strain in the experimental superalloy were measured by electronic probe microanalysis (EPMA) and electron back-scattered diffraction (EBSD) technique. It was indicated that the gradient of element distribution was anisotropic and the inner strain between dendrite core and interdendritic regions was different even after 24,000 h of exposure at 1173 K, which influenced the kinetics for the dendrite coarsening of γ' phase.

Additive Manufacturing of Nickel Superalloys: Opportunities for Innovation and Challenges Related to Qualification

Science.gov (United States)

Babu, S. S.; Raghavan, N.; Raplee, J.; Foster, S. J.; Frederick, C.; Haines, M.; Dinwiddie, R.; Kirka, M. K.; Plotkowski, A.; Lee, Y.; Dehoff, R. R.

2018-06-01

Innovative designs for turbines can be achieved by advances in nickel-based superalloys and manufacturing methods, including the adoption of additive manufacturing. In this regard, selective electron beam melting (SEBM) and selective laser melting (SLM) of nickel-based superalloys do provide distinct advantages. Furthermore, the direct energy deposition (DED) processes can be used for repair and reclamation of nickel alloy components. The current paper explores opportunities for innovation and qualification challenges with respect to deployment of AM as a disruptive manufacturing technology. In the first part of the paper, fundamental correlations of processing parameters to defect tendency and microstructure evolution will be explored using DED process. In the second part of the paper, opportunities for innovation in terms of site-specific control of microstructure during processing will be discussed. In the third part of the paper, challenges in qualification of AM parts for service will be discussed and potential methods to alleviate these issues through in situ process monitoring, and big data analytics are proposed.

Metallurgical joining of engine parts. Inertia welding of nickel superalloy HP compressor disks

International Nuclear Information System (INIS)

Ferte, J.P.

1993-01-01

The main part of this paper describes upside metallurgical and mechanical work done at SNECMA, on inertia welding of powder metallurgy nickel base superalloys ASTROLOY and N18, allowing appliance of this process to engine parts : Inertia welding of superalloys leads to deap microstructural changes in the H.A.Z. which have been, as well as upset, correlated to process parameters, weld geometry and base material microstructure; a full mechanical testing of welds shown properties equivalent to base material ones up to 650 C except for fatigue crack growth behavior under specific conditions (T>600 C-hold time at maximum load) which is drastically reduced for in weld plane propagation. A significant improvement of this later property has been done through post-welding heat treatment and optimization of welding parameters. Last part of this paper summarize the main teachings gained, on the complete welding procedure, from welding of scale one parts. (orig.)

Phosphorus in Agriculture : 100 % Zero

NARCIS (Netherlands)

Schnug, Ewald; De Kok, Luit J.

2016-01-01

Phosphorus is essential for all living organisms, reserves in geogenic deposits are finite, and phosphorus nutrient mining and oversupply are common phenomenons on agricultural soils. Only if the agricultural phosphorus cycle can be closed and the fertilized nutrient been utilized completely,

Synergistic effect of rhenium and ruthenium in nickel-based single-crystal superalloys

Energy Technology Data Exchange (ETDEWEB)

Yu, X.X. [Department of Physics, Tsinghua University, Beijing 100084 (China); Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Wang, C.Y., E-mail: cywang@mail.tsinghua.edu.cn [Department of Physics, Tsinghua University, Beijing 100084 (China); Central Iron and Steel Research Institute, Beijing 100081 (China); Zhang, X.N. [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China); Yan, P. [Central Iron and Steel Research Institute, Beijing 100081 (China); Zhang, Z., E-mail: zezhang@zju.edu.cn [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

2014-01-05

Highlights: • Re and Ru synergistic effects in nickel-based superalloys are investigated. • The Al site occupation of Re atom in the γ′ phase is observed directly. • The addition of Ru results in the repartitioning of Re to γ phase. -- Abstract: The microstructures of ternary Ni–Al–Re and quaternary Ni–Al–Re–Ru single-crystal alloys were investigated at atomic and electronic levels to clarify the synergistic effect of Re and Ru in nickel-based single-crystal superalloys. In the Ni–Al–Re alloy, it was directly observed that Re atom occupied the Al site of γ′ phase. In the Ni–Al–Re–Ru alloy, the mechanisms of Re repartition between γ and γ′ phases were proposed. In the dendritic cores, high concentrations of Re exceeded the solubility limit of γ′ phase and partitioned to γ phase, which led to the homogenization. In the interdendritic regions, Ru resulted in the repartitioning of Re to γ phase which was proved by transmission electron microscopy and first-principles calculations.

Residual Stresses in a NiCrY-Coated Powder Metallurgy Disk Superalloy

Science.gov (United States)

Gabb, Timothy P.; Rogers, Richard B.; Nesbitt, James A.; Puleo, Bernadette J.; Miller, Robert A.; Telesman, Ignacy; Draper, Susan L.; Locci, Ivan E.

2017-01-01

Protective ductile coatings will be necessary to mitigate oxidation and corrosion attack on superalloy disks exposed to increasing operating temperatures in some turbine engine environments. However, such coatings must be resistant to harmful surface cracking during service. The objective of this study was to investigate how residual stresses evolve in such coatings. Cylindrical gage fatigue specimens of powder metallurgy-processed disk superalloy LSHR were coated with a NiCrY coating, shot peened, and then subjected to fatigue in air at room and high temperatures. The effects of shot peening and fatigue cycling on average residual stresses and other aspects of the coating were assessed. Shot peening did induce beneficial compressive residual stresses in the coating and substrate. However, these stresses became more tensile in the coating with subsequent heating and contributed to cracking of the coating in long intervals of cycling at 760 C. Substantial compressive residual stresses remained in the substrate adjacent to the coating, sufficient to suppress fatigue cracking. The coating continued to protect the substrate from hot corrosion pitting, even after fatigue cracks initiated in the coating.

Phosphorus poisoning in waterfowl

Science.gov (United States)

Coburn, D.R.; DeWitt, J.B.; Derby, J.V.; Ediger, E.

1950-01-01

Black ducks and mallards were found to be highly susceptible to phosphorus poisoning. 3 mg. of white phosphorus per kg. of body weight given in a single dose resulted in death of a black duck in 6 hours. Pathologic changes in both acute and chronic poisoning were studied. Data are presented showing that diagnosis can be made accurately by chemical analysis of stored tissues in cases of phosphorus poisoning.

Oxidation behavior and compositional analysis of aluminized superalloy

International Nuclear Information System (INIS)

Khalid, F.A.; Nawaz, F.

2003-01-01

The high temperature oxidation behavior of superalloy specimens used for the manufacture of turbine blades has been examined using scanning electron microscopy (SEM) and fine-probe spot and line scan EDS microanalysis techniques. The performance of aluminized coating applied to the specimens has also been examined. It was observed that complex oxides are formed in both coated and uncoated specimens. However the coated specimens revealed a greater stability of gamma phase and integrity of aluminized coating as compared with uncoated specimens. The microchemical and microstructural changes that occurred during oxidation have been analyzed to examine characteristics of oxide layers. (author)

Phosphorus oxide gate dielectric for black phosphorus field effect transistors

Science.gov (United States)

Dickerson, W.; Tayari, V.; Fakih, I.; Korinek, A.; Caporali, M.; Serrano-Ruiz, M.; Peruzzini, M.; Heun, S.; Botton, G. A.; Szkopek, T.

2018-04-01

The environmental stability of the layered semiconductor black phosphorus (bP) remains a challenge. Passivation of the bP surface with phosphorus oxide, POx, grown by a reactive ion etch with oxygen plasma is known to improve photoluminescence efficiency of exfoliated bP flakes. We apply phosphorus oxide passivation in the fabrication of bP field effect transistors using a gate stack consisting of a POx layer grown by reactive ion etching followed by atomic layer deposition of Al2O3. We observe room temperature top-gate mobilities of 115 cm2 V-1 s-1 in ambient conditions, which we attribute to the low defect density of the bP/POx interface.

Sewage-effluent phosphorus: A greater risk to river eutrophication than agricultural phosphorus?

International Nuclear Information System (INIS)

Jarvie, Helen P.; Neal, Colin; Withers, Paul J.A.

2006-01-01

Phosphorus (P) concentrations from water quality monitoring at 54 UK river sites across seven major lowland catchment systems are examined in relation to eutrophication risk and to the relative importance of point and diffuse sources. The over-riding evidence indicates that point (effluent) rather than diffuse (agricultural) sources of phosphorus provide the most significant risk for river eutrophication, even in rural areas with high agricultural phosphorus losses. Traditionally, the relative importance of point and diffuse sources has been assessed from annual P flux budgets, which are often dominated by diffuse inputs in storm runoff from intensively managed agricultural land. However, the ecological risk associated with nuisance algal growth in rivers is largely linked to soluble reactive phosphorus (SRP) concentrations during times of ecological sensitivity (spring/summer low-flow periods), when biological activity is at its highest. The relationships between SRP and total phosphorus (TP; total dissolved P + suspended particulate P) concentrations within UK rivers are evaluated in relation to flow and boron (B; a tracer of sewage effluent). SRP is the dominant P fraction (average 67% of TP) in all of the rivers monitored, with higher percentages at low flows. In most of the rivers the highest SRP concentrations occur under low-flow conditions and SRP concentrations are diluted as flows increase, which is indicative of point, rather than diffuse, sources. Strong positive correlations between SRP and B (also TP and B) across all the 54 river monitoring sites also confirm the primary importance of point source controls of phosphorus concentrations in these rivers, particularly during spring and summer low flows, which are times of greatest eutrophication risk. Particulate phosphorus (PP) may form a significant proportion of the phosphorus load to rivers, particularly during winter storm events, but this is of questionable relevance for river eutrophication

Hydrogen Annealing Of Single-Crystal Superalloys

Science.gov (United States)

Smialek, James L.; Schaeffer, John C.; Murphy, Wendy

1995-01-01

Annealing at temperature equal to or greater than 2,200 degrees F in atmosphere of hydrogen found to increase ability of single-crystal superalloys to resist oxidation when subsequently exposed to oxidizing atmospheres at temperatures almost as high. Supperalloys in question are principal constituents of hot-stage airfoils (blades) in aircraft and ground-based turbine engines; also used in other high-temperature applications like chemical-processing plants, coal-gasification plants, petrochemical refineries, and boilers. Hydrogen anneal provides resistance to oxidation without decreasing fatigue strength and without need for coating or reactive sulfur-gettering constituents. In comparison with coating, hydrogen annealing costs less. Benefits extend to stainless steels, nickel/chromium, and nickel-base alloys, subject to same scale-adhesion and oxidation-resistance considerations, except that scale is chromia instead of alumina.

Effect of phosphorus sources on phosphorus and nitrogen utilization by three sweet potato cultivars

International Nuclear Information System (INIS)

Montanez, A.; Zapata, F.; Kumarasinghe, K.S.

1996-01-01

A greenhouse experiment was conducted at the FAO/IAEA Agriculture and Biotechnology Laboratory in Seibersdorf, Austria using three sweet potato cultivars, TIS 2, TIS 3053 and TIS 1487. The three sweet potato cultivars were grown at two levels of phosphorus (0 kg P/kg soil and 60 kg P/kg soil). The fertilizer treatments consisted of two sources of phosphorus, Gafza rock Phosphate and triple super phosphate with 14.19 and 19.76% total phosphorus, respectively. 15 N labelled urea was used to study the nitrogen recovery in tubers from the applied nitrogen fertilizer. The results from these preliminary studies indicate that there is considerable genotypic variation among cultivars in the efficiency with which phosphorus and nitrogen are taken up and used to produce biomass. Their response to different sources of phosphorus are also variable. TIS-2 and TIS-1487 have a greater ability to absorb phosphorus from Gafza rock phosphate and produce higher tube yields indicating their greater potential for using alternative sources of natural phosphate fertilizers more effectively. Gafza rock phosphate also increased accumulation of nitrogen in TIS-1487, a characteristic which will place this cultivar at an advantage when growing in soils low in nitrogen. On an overall basis taking into account tuber yield, phosphorus use efficiency, and nitrogen use efficiency, TIS-2 may be considered the better candidate for introduction into soils poor in resources particularly phosphorus. This study was conducted with a limited number of cultivars due to limitation in the availability of germplasma. In spite of this, the differences in their abilities for phosphorus and nitrogen uptake and use are clearly visible which justifies large scale screening experiments using a broader germplasm base, in the future. (author). 14 refs, 1 fig., 3 tabs

Effect of phosphorus sources on phosphorus and nitrogen utilization by three sweet potato cultivars

Energy Technology Data Exchange (ETDEWEB)

Montanez, A; Zapata, F [FAO/IAEA Agriculture and Biotechnology Lab., Seibersdorf (Austria). Soils Science Unit; Kumarasinghe, K S [Joint FAO/IAEA Div. of Nuclear Techniques in Food and Agriculture, Vienna (Austria). Soil Fertility, Irrigation and Crop Production Section

1996-07-01

A greenhouse experiment was conducted at the FAO/IAEA Agriculture and Biotechnology Laboratory in Seibersdorf, Austria using three sweet potato cultivars, TIS 2, TIS 3053 and TIS 1487. The three sweet potato cultivars were grown at two levels of phosphorus (0 kg P/kg soil and 60 kg P/kg soil). The fertilizer treatments consisted of two sources of phosphorus, Gafza rock Phosphate and triple super phosphate with 14.19 and 19.76% total phosphorus, respectively. {sup 15}N labelled urea was used to study the nitrogen recovery in tubers from the applied nitrogen fertilizer. The results from these preliminary studies indicate that there is considerable genotypic variation among cultivars in the efficiency with which phosphorus and nitrogen are taken up and used to produce biomass. Their response to different sources of phosphorus are also variable. TIS-2 and TIS-1487 have a greater ability to absorb phosphorus from Gafza rock phosphate and produce higher tube yields indicating their greater potential for using alternative sources of natural phosphate fertilizers more effectively. Gafza rock phosphate also increased accumulation of nitrogen in TIS-1487, a characteristic which will place this cultivar at an advantage when growing in soils low in nitrogen. On an overall basis taking into account tuber yield, phosphorus use efficiency, and nitrogen use efficiency, TIS-2 may be considered the better candidate for introduction into soils poor in resources particularly phosphorus. This study was conducted with a limited number of cultivars due to limitation in the availability of germplasma. In spite of this, the differences in their abilities for phosphorus and nitrogen uptake and use are clearly visible which justifies large scale screening experiments using a broader germplasm base, in the future. (author). 14 refs, 1 fig., 3 tabs.

Creep Behaviour of Modified Mar-247 Superalloy

Directory of Open Access Journals (Sweden)

Cieśla M.

2016-06-01

Full Text Available The paper presents the results of analysis of creep behaviour in short term creep tests of cast MAR-247 nickel-based superalloy samples made using various modification techniques and heat treatment. The accelerated creep tests were performed under temperature of 982 °C and the axial stresses of σ = 150 MPa (variant I and 200 MPa (variant II. The creep behaviour was analysed based on: creep durability (creep rupture life, steady-state creep rate and morphological parameters of macro- and microstructure. It was observed that the grain size determines the creep durability in case of test conditions used in variant I, durability of coarse-grained samples was significantly higher.

Initial Mechanical Testing of Superalloy Lattice Block Structures Conducted

Science.gov (United States)

Krause, David L.; Whittenberger, J. Daniel

2002-01-01

The first mechanical tests of superalloy lattice block structures produced promising results for this exciting new lightweight material system. The testing was performed in-house at NASA Glenn Research Center's Structural Benchmark Test Facility, where small subelement-sized compression and beam specimens were loaded to observe elastic and plastic behavior, component strength levels, and fatigue resistance for hundreds of thousands of load cycles. Current lattice block construction produces a flat panel composed of thin ligaments arranged in a three-dimensional triangulated trusslike structure. Investment casting of lattice block panels has been developed and greatly expands opportunities for using this unique architecture in today's high-performance structures. In addition, advances made in NASA's Ultra-Efficient Engine Technology Program have extended the lattice block concept to superalloy materials. After a series of casting iterations, the nickel-based superalloy Inconel 718 (IN 718, Inco Alloys International, Inc., Huntington, WV) was successfully cast into lattice block panels; this combination offers light weight combined with high strength, high stiffness, and elevated-temperature durability. For tests to evaluate casting quality and configuration merit, small structural compression and bend test specimens were machined from the 5- by 12- by 0.5-in. panels. Linear elastic finite element analyses were completed for several specimen layouts to predict material stresses and deflections under proposed test conditions. The structural specimens were then subjected to room-temperature static and cyclic loads in Glenn's Life Prediction Branch's material test machine. Surprisingly, the test results exceeded analytical predictions: plastic strains greater than 5 percent were obtained, and fatigue lives did not depreciate relative to the base material. These assets were due to the formation of plastic hinges and the redundancies inherent in lattice block construction

SEQUENTIAL ELECTRODIALYTIC EXTRACTION OF PHOSPHORUS COMPOUNDS

DEFF Research Database (Denmark)

2017-01-01

The present invention relates to an apparatus for electrodialytic extraction of phosphorus from a particulate material in suspension and to a method for electrodialytic phosphorus recovery, which uses the apparatus. The method may be applied for wastewater treatment, and/or treatment of particulate...... material rich in phosphorus. The present invention provides an apparatus for electrodialytic extraction of phosphorus from a particulate material comprising acidic and/or alkaline soluble phosphorus compounds, in suspension, comprising: • a first electrodialytic cell comprising a first anolyte compartment...

Influence of γ' precipitates on Portevin–Le Chatelier effect of Ni-based superalloys

Energy Technology Data Exchange (ETDEWEB)

Cai, Yulong [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230027 (China); Tian, Chenggang [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Fu, Shihua, E-mail: fushihua@ustc.edu.cn [CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230027 (China); Han, Guoming [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Cui, Chuanyong, E-mail: chycui@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Zhang, Qingchuan, E-mail: zhangqc@ustc.edu.cn [CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230027 (China)

2015-06-25

The γ′ precipitate plays a critical role in improving the mechanical properties of Ni-based superalloys. An undesirable phenomenon referred to as the Portevin–Le Chatelier (PLC) effect always appears in Ni-based superalloys deformed within specific ranges of strain rate and temperature. In order to systematically investigate the influence of the γ′ precipitates on the PLC effect, four Ni-based superalloys with various γ′ contents were designed and fabricated. Microscopic observations from transmission electron microscopy (TEM) indicated that the volume fraction of the γ′ phase was consistent with the designed value. Furthermore, analysis of energy dispersive spectroscopy (EDS) results revealed that the γ matrix of all the alloys consisted of the same components. Uniaxial tensile tests were performed at strain rates and temperatures ranging from 1×10{sup −4} to 3×10{sup −3} s{sup −1} and 300–500 °C, respectively. We found that the ultimate strength increased while the elongation decreased with increasing γ′ content. In addition, the serration changed from type A to type B and to type C with increasing temperature, decreasing strain rate or increasing γ′ content; the amplitude of type B serrations was described by unimodal or bimodal distributions. Increasing volume fraction of γ′ precipitates shifted the region in which the PLC effect occurred, to the range of low temperatures and high strain rates. Moreover, the serration amplitude increased with increasing γ′ content at a given temperature, which indicated that the γ′ precipitate increases the dynamic strain ageing (DSA) effect.

SANS investigation of precipitate microstructure in nickel-base superalloys Waspaloy and DT750

Czech Academy of Sciences Publication Activity Database

Strunz, Pavel; Zrník, J.; Seliga, T.; Penkalla, H.J.

2006-01-01

Roč. 2, č. 23 (2006), s. 363-368 ISSN 0044-2968 R&D Projects: GA ČR GA202/06/0601 Institutional research plan: CEZ:AV0Z10480505 Keywords : small-angle-neutron scattering * superalloys * precipitation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.897, year: 2006

Nanoscale Origins of the Size Effect in the Compression Response of Single Crystal Ni-Base Superalloy Micro-Pillars

Directory of Open Access Journals (Sweden)

Siqi Ying

2018-04-01

Full Text Available Nickel superalloys play a pivotal role in enabling power-generation devices on land, sea, and in the air. They derive their strength from coherent cuboidal precipitates of the ordered γ’ phase that is different from the γ matrix in composition, structure and properties. In order to reveal the correlation between elemental distribution, dislocation glide and the plastic deformation of micro- and nano-sized volumes of a nickel superalloy, a combined in situ nanoindentation compression study was carried out with a scanning electron microscope (SEM on micro- and nano-pillars fabricated by focused ion beam (FIB milling of Ni-base superalloy CMSX4. The observed mechanical response (hardening followed by softening was correlated with the progression of crystal slip that was revealed using FIB nano-tomography and energy-dispersive spectroscopy (EDS elemental mapping. A hypothesis was put forward that the dependence of material strength on the size of the sample (micropillar diameter is correlated with the characteristic dimension of the structural units (γ’ precipitates. By proposing two new dislocation-based models, the results were found to be described well by a new parameter-free Hall–Petch equation.

Phosphorus containing sintered alloys (review)

International Nuclear Information System (INIS)

Muchnik, S.V.

1984-01-01

Phosphorus additives are considered for their effect on the properties of sintered alloys of different applications: structural, antifriction, friction, magnetic, hard, superhard, heavy etc. Data are presented on compositions and properties of phosphorus-containing materials produced by the powder metallurgy method. Phosphorus is shown to be an effective activator of sintering in some cases. When its concentration in the material is optimal it imparts the material such properties as strength, viscosity, hardness, wear resistance. Problems concerning powder metallurgy of amorphous phosphorus-containing alloys are reported

Phosphorus and the dairy cow

OpenAIRE

Ekelund, Adrienne

2003-01-01

The general aim of the present work was to investigate phosphorus balance in the dairy cow, with reference to the amount and source of phosphorus. Furthermore, biochemical bone markers were used to study the bone turnover during the lactation and dry period. Phosphorus is located in every cell of the body and has more known functions than any other mineral element in the animal body. Phosphorus is also an important constituent of milk, and is therefore required in large amounts in a high yiel...

Surface modification, microstructure and mechanical properties of investment cast superalloy

OpenAIRE

M. Zielińska; K. Kubiak; J. Sieniawski

2009-01-01

Purpose: The aim of this work is to determine physical and chemical properties of cobalt aluminate (CoAl2O4) modifiers produced by different companies and the influence of different types of modifiers on the grain size, the microstructure and mechanical properties of high temperature creep resisting superalloy René 77.Design/methodology/approach: The first stage of the research work took over the investigations of physical and chemical properties of cobalt aluminate manufactured by three diff...

Fertilizer phosphorus in some Finnish soils

Directory of Open Access Journals (Sweden)

Armi Kaila

1961-01-01

Full Text Available In the present paper it is tried to trace the fate of fertilizer phosphorus in soil by comparing the analyses of soils from treated and untreated plots of field trials. This indirect approach cannot be expected to provide exact values, but it is likely to give an approximate answer. The results reported above do not in any marked degree change our present conception of the forms in which fertilizer phosphorus accumulates in soils. In the acid soils studied (pH 4—6.4 in 0.02 N CaCl2 superphosphate tended to increase the fractions which were extracted by NH4F or NaOH. Hyperphosphate phosphorus was mostly found in the acid-soluble fraction. During a longer period of dressing with phosphate an increase in the organic phosphorus content of a peat soil could be detected. In the incubation experiments the mineralization of organic phosphorus occurred at a higher rate in the samples from the plots treated with superphosphate than in those from the untreated one. It might be supposed that the organic phosphorus mineralized mainly originated from the plant residues. It seems that the fractionation method developed by CHANG and JACKSON (4 for the estimation of discrete forms of soil phosphorus is not quite satisfactory for tracing the fertilizer phosphorus in soils recently dressed with phosphates. In particular, it may be fallacious to conclude that the fraction extracted by NH4F would only represent phosphorus bound to aluminium and its compounds. At least in the absence of soil, a large part of phosphorus in dicalcium phosphate dihydrate falls into this fraction, and also a small amount of hyperphosphate phosphorus may be found in it. The test values for »available» phosphorus showed the effect of fertilizers in accordance with previous observations (9, 13. Acetic acid soluble P revealed the treatment with hyperphosphate, but only slightly the application of superphosphate. The test value for the sorbed P of BRAY and KURTZ (2, or phosphorus

Compositional variations for small-scale gamma prime (γ′) precipitates formed at different cooling rates in an advanced Ni-based superalloy

International Nuclear Information System (INIS)

Chen, Y.Q.; Francis, E.; Robson, J.; Preuss, M.; Haigh, S.J.

2015-01-01

Size-dependent compositional variations under different cooling regimes have been investigated for ordered L1 2 -structured gamma prime (γ′) precipitates in the commercial powder metallurgy Ni-based superalloy RR1000. Using scanning transmission electron microscope imaging combined with absorption-corrected energy-dispersive X-ray spectroscopy, we have discovered large differences in the Al, Ti and Co compositions for γ′ precipitates in the size range 10–300 nm. Our experimental results, coupled with complementary thermodynamic calculations, demonstrate the importance of kinetic factors on precipitate composition in Ni-based superalloys. In particular, these results provide new evidence for the role of elemental diffusion kinetics and aluminium antisite atoms on the low-temperature growth kinetics of fine-scale γ′ precipitates. Our findings have important implications for understanding the microstructure and precipitation behaviour of Ni-based superalloys, suggesting a transition in the mechanism of vacancy-mediated diffusion of Al from intrasublattice exchange at high temperatures to intersublattice antisite-assisted exchange at low temperatures

Behaviour and damage of a superalloy prepared by hot isostatic compression

International Nuclear Information System (INIS)

Dubiez-Le-Goff, Sophie

2003-01-01

This work deals with the behavior and damage of Udimet 720 superalloy prepared by hot isostatic compression. This alloy is considered for manufacturing turbine disks of high temperature reactors (HTR). The material choice for HTR turbine disk depends on the following criteria: a good creep resistance until 700 C, a good behaviour under an helium impure atmosphere, a possible implementation under a disk of 1.5 m diameter. (author) [fr

Creep Crack Initiation and Growth Behavior for Ni-Base Superalloys

Science.gov (United States)

Nagumo, Yoshiko; Yokobori, A. Toshimitsu, Jr.; Sugiura, Ryuji; Ozeki, Go; Matsuzaki, Takashi

The structural components which are used in high temperature gas turbines have various shapes which may cause the notch effect. Moreover, the site of stress concentration might have the heterogeneous microstructural distribution. Therefore, it is necessary to clarify the creep fracture mechanism for these materials in order to predict the life of creep fracture with high degree of accuracy. In this study, the creep crack growth tests were performed using in-situ observational testing machine with microscope to observe the creep damage formation and creep crack growth behavior. The materials used are polycrystalline Ni-base superalloy IN100 and directionally solidified Ni-base superalloy CM247LC which were developed for jet engine turbine blades and gas turbine blades in electric power plants, respectively. The microstructural observation of the test specimens was also conducted using FE-SEM/EBSD. Additionally, the analyses of two-dimensional elastic-plastic creep finite element using designed methods were conducted to understand the effect of microstructural distribution on creep damage formation. The experimental and analytical results showed that it is important to determine the creep crack initiation and early crack growth to predict the life of creep fracture and it is indicated that the highly accurate prediction of creep fracture life could be realized by measuring notch opening displacement proposed as the RNOD characteristic.

Effect of Squareness of Initial γ' Precipitates on Creep-Rupture Life of a Ni-Base Single Crystal Superalloy at 760/982 °C

Science.gov (United States)

Shi, Zhenbin; Peng, Zhifang; Luo, Yushi; Xie, Hongji; Jin, Haipeng; Zhao, Yunsong; Mei, Qingsong

2018-05-01

An approach to determination of squareness of initial γ' precipitates (S 2D) is proposed to evaluate its effect on creep-rupture life (t r) of nickel-base single crystal (SC) superalloys. It is found that the 760/982 °C rupture life varied with the change in regional S 2D caused by redistribution of W when 1st-step aging temperature changed in full heat treatment on superalloy DD83 investigated. The longest creep-rupture life occurred at the highest value/the lowest difference in S 2D in the interdendritic regions/between the typical dendritic regions in DD83. It is also found that S 2D is a weighted function of the area fraction (F 2D), spacing (h), and size (d) of γ' precipitates and is closely related to t r in a series of SC superalloys. In addition, the variation of S 2D with F 2D (here, thermodynamic mole fraction is approximately expressed by F 2D) through lattice misfit (δ) in the SC superalloys with F 2D ranging from 60 to 75 pct is well correlated. Therefore, to reveal and to better understand these relationships and correlations may help to optimize the phase variables in order to achieve a long rupture life of SC superalloys. In addition, functions to reveal the interrelationships of F 2D, volume fraction (F 3D), S 2D, and cuboidness (S 3D) of initial γ' precipitates are derived considering their shape changes. All of these are hoped to be helpful in practical applications and in understanding the true meaning of the related variables.

Heat affected zone liquation cracking in electron beam welded third generation nickel base superalloys

International Nuclear Information System (INIS)

Ojo, O.A.; Wang, Y.L.; Chaturvedi, M.C.

2008-01-01

The weldability of directionally solidified nickel base superalloy TMS-75 and TMS-75+C was investigated by autogenous bead-on-plate electron beam welding. The analysis of microsegregation that occurred during solidification of the as-cast alloys indicated that while W and Re segregated into the γ dendrites of both the alloys, Ta, Hf and C were rejected into the interdendritic liquid in the TMS-75+C. Heat affected zone intergranular liquation cracking was observed in both the materials and was observed to be closely associated with liquated γ-γ' eutectic microconstituent. The TMS-75+C alloy, however, exhibited a reduced extent of HAZ cracking compared to TMS-75. Suppression of terminal solidification reaction involving non-invariant γ-γ' eutectic transformation due to modification of primary solidification path by carbon addition is suggested to be an important factor contributing to reduced susceptibility of TMS-75+C alloy to HAZ liquation cracking relative to the TMS-75 superalloy

Phosphorus Regulation in Chronic Kidney Disease.

Science.gov (United States)

Suki, Wadi N; Moore, Linda W

2016-01-01

Serum phosphorus levels stay relatively constant through the influence of multiple factors-such as parathyroid hormone, fibroblast growth factor 23, and vitamin D-on the kidney, bone, and digestive system. Whereas normal serum phosphorus ranges between 3 mg/dL to 4.5 mg/dL, large cross-sectional studies have shown that even people with normal kidney function are sometimes found to have levels ranging between 1.6 mg/dL and 6.2 mg/dL. While this may partially be due to diet and the factors mentioned above, total understanding of these atypical ranges of serum phosphorus remains uncertain. Risks for bone disease are high in people aged 50 and older, and this group comprises a large proportion of people who also have chronic kidney disease. Consuming diets low in calcium and high in phosphorus, especially foods with phosphate additives, further exacerbates bone turnover. Existing bone disease increases the risk for high serum phosphorus, and higher serum phosphorus has been associated with increased adverse events and cardiovascular-related mortality both in people with chronic kidney disease and in those with no evidence of disease. Once kidney function has deteriorated to end-stage disease (Stage 5), maintaining normal serum phosphorus requires dietary restrictions, phosphate-binding medications, and dialysis. Even so, normal serum phosphorus remains elusive in many patients with Stage 5 kidney disease, and researchers are testing novel targets that may inhibit intestinal transport of phosphorus to achieve better phosphate control. Protecting and monitoring bone health should also aid in controlling serum phosphorus as kidney disease advances.

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

High-temperature γ (FCC/γ′ (L12 Co-Al-W based superalloys

Directory of Open Access Journals (Sweden)

Knop Matthias

2014-01-01

Full Text Available Interim results from the development of a polycrystalline Co-Al-W based superalloy are presented. Cr has been added to provide oxidation resistance and Ni has then been added to widen and stabilise the γ′ phase field. The alloy presented has a solvus of 1010 °C and a density of 8.7 g cm−3. The room temperature flow stress is over 1000 MPa and this reduces dramatically above 800 °C. The flow stress anomaly is observed. A microstructure with both ∼ 50 nm γ′ produced on cooling and larger 100–200 nm γ′ can be obtained. Isothermal oxidation at 800 °C in air for 200 h gave a mass gain of 0.96 mg cm−2. After hot deformation in the 650–850 °C temperature range, both anti phase boundaries (APBs and stacking faults could be observed. An APB energy of 71 mJ m−2 was measured, which is comparable to that found in commercial nickel superalloys.

Experimental investigation on the spiral trepanning of K24 superalloy with femtosecond laser

Science.gov (United States)

Wang, Maolu; Yang, Lijun; Zhang, Shuai; Wang, Yang

2018-05-01

Film cooling holes are crucial for improving the performance of the aviation engine. In the paper, the processing of the film cooling holes on K24 superalloy by femtosecond laser is investigated. By comparing the three different drilling methods, the spiral trepanning method is chosen, and all the drilling experiments are carried out in this way. The experimental results show that the drilling of femtosecond laser pulses has distinct merits against that of the traditional long pulse laser, which can realize the "cold" processing with less recasting layer and less crack. The influence of each process parameter on roundness and taper, which are the important parameters to measure the quality of holes, is analyzed in detail, and the method to decrease it is proposed. To further reduce the recasting layer, the processing quality of the inner wall of the micro hole is investigated by scanning electron microscopy (SEM) equipped with energy disperse spectroscopy (EDS), the mechanism of the femtosecond laser interaction with K24 superalloy is further revealed. The investigation to the film hole machining by femtosecond laser has important practical significance.

Computer aided design of nickel-base superalloys

International Nuclear Information System (INIS)

Lawrence, P.J.

1988-01-01

This paper describes a computer aided design process for Ni-base superalloys developed and employed at ASEA Brown Boveri. The technique involves a series of modules each of which predicts a particular property of a hypothetical new composition. In the first stage of the development of this design techniques modules were produced to predict phase stability, using PHACOMP, and high temperature creep strength and hot corrosion resistance, using multiple linear regression equations derived from the data in the literature. Alloys designed using these technique are also discussed and, in particular, shortcomings of the design process are highlighted. This information was then used to produce a revamped design methodology involving extra modules, including prediction of an alloy's gamma-prime content. (orig.)

Phosphorus and Nutrition in Chronic Kidney Disease

Directory of Open Access Journals (Sweden)

Emilio González-Parra

2012-01-01

Full Text Available Patients with renal impairment progressively lose the ability to excrete phosphorus. Decreased glomerular filtration of phosphorus is initially compensated by decreased tubular reabsorption, regulated by PTH and FGF23, maintaining normal serum phosphorus concentrations. There is a close relationship between protein and phosphorus intake. In chronic renal disease, a low dietary protein content slows the progression of kidney disease, especially in patients with proteinuria and decreases the supply of phosphorus, which has been directly related with progression of kidney disease and with patient survival. However, not all animal proteins and vegetables have the same proportion of phosphorus in their composition. Adequate labeling of food requires showing the phosphorus-to-protein ratio. The diet in patients with advanced-stage CKD has been controversial, because a diet with too low protein content can favor malnutrition and increase morbidity and mortality. Phosphorus binders lower serum phosphorus and also FGF23 levels, without decreasing diet protein content. But the interaction between intestinal dysbacteriosis in dialysis patients, phosphate binder efficacy, and patient tolerance to the binder could reduce their efficiency.

Unit-cell design for two-dimensional phase-field simulation of microstructure evolution in single-crystal Ni-based superalloys during solidification

Directory of Open Access Journals (Sweden)

Dongjia Cao

2017-12-01

Full Text Available Phase-field simulation serves as an effective tool for quantitative characterization of microstructure evolution in single-crystal Ni-based superalloys during solidification nowadays. The classic unit cell is either limited to γ dendrites along crystal orientation or too ideal to cover complex morphologies for γ dendrites. An attempt to design the unit cell for two-dimensional (2-D phase-field simulations of microstructure evolution in single-crystal Ni-based superalloys during solidification was thus performed by using the MICRESS (MICRostructure Evolution Simulation Software in the framework of the multi-phase-field (MPF model, and demonstrated in a commercial TMS-113 superalloy. The coupling to CALPHAD (CALculation of PHAse Diagram thermodynamic database was realized via the TQ interface and the experimental diffusion coefficients were utilized in the simulation. Firstly, the classic unit cell with a single γ dendrite along crystal orientation was employed for the phase-field simulation in order to reproduce the microstructure features. Then, such simple unit cell was extended into the cases with two other different crystal orientations, i.e., and . Thirdly, for crystal orientations, the effect of γ dendritic orientations and unit cell sizes on microstructure and microsegregation was comprehensively studied, from which a new unit cell with multiple γ dendrites was proposed. The phase-field simulation with the newly proposed unit cell was further performed in the TMS-113 superalloy, and the microstructure features including the competitive growth of γ dendrites, microsegregation of different solutes and distribution of γ′ grains, can be nicely reproduced.

The location and nature of accumulated phosphorus in seven sludges from activated sludge plants which exhibited enhanced phosphorus removal

International Nuclear Information System (INIS)

Buchan, L.

1981-01-01

Electron microscopy combined with the energy dispersive analysis of X-rays (EDX) has been used to examine the nature of the phosphorus accumulated in sludges from seven activated sludge plants exhibiting enhanced phosphorus removal. Large phosphorus accumulations were located in identical structures in the sludges examined. The phosphorus was located in large electron-dense bodies, within large bacterial cells which were characteristically grouped in clusters. The calcium:phosphorus ratio of these electron-dense bodies precluded them from being any form of calcium phosphate precipitate. Quantitative analysis indicated that the electron-dense bodies contained in excess of 30% phosphorus. The results obtained are supportive of a biological mechanism of enhanced phosphorus uptake in activated sludge

Refractory metal based superalloys

International Nuclear Information System (INIS)

Alonso, Paula R.; Vicente, Eduardo E.; Rubiolo, Gerardo H.

1999-01-01

Refractory metals are looked as promising materials for primary circuits in fission reactors and even as fusion reactor components. Indeed, superalloys could be developed which take advantage of their high temperature properties together with the benefits of a two- phase (intermetallic compound-refractory metal matrix) coherent structure. In 1993, researchers of the Office National d'Etudes et de Recherches Aerospatiales of France reported the observation of such a coherent structure in the Ta-Ti-Zr-Al-Nb-Mo system although the exact composition is not reported. The intermetallic compound would be Ti 2 AlMo based. However, the formation of this compound and its possible coexistence with a disordered bcc phase in the ternary system Ti-Al-Mo is a controversial subject in the related literature. In this work we develop a technique to obtain homogeneous alloys samples with 50 Ti-25 Al-25 Mo composition. The resulting specimens were characterized by optical and electronic metallography (SEM), microprobe composition measurements (EPMA) and X-ray diffraction (XRD) analyses. The results show the evidence for a bcc (A2→B2) ordering reaction in the Ti-Al-Mo system in the 50 Ti-25 Al-25 Mo composition. (author)

Phosphorus vacancy cluster model for phosphorus diffusion gettering of metals in Si

Energy Technology Data Exchange (ETDEWEB)

Chen, Renyu; Trzynadlowski, Bart; Dunham, Scott T. [Department of Electrical Engineering, University of Washington, Seattle, Washington 98195 (United States)

2014-02-07

In this work, we develop models for the gettering of metals in silicon by high phosphorus concentration. We first performed ab initio calculations to determine favorable configurations of complexes involving phosphorus and transition metals (Fe, Cu, Cr, Ni, Ti, Mo, and W). Our ab initio calculations found that the P{sub 4}V cluster, a vacancy surrounded by 4 nearest-neighbor phosphorus atoms, which is the most favorable inactive P species in heavily doped Si, strongly binds metals such as Cu, Cr, Ni, and Fe. Based on the calculated binding energies, we build continuum models to describe the P deactivation and Fe gettering processes with model parameters calibrated against experimental data. In contrast to previous models assuming metal-P{sub 1}V or metal-P{sub 2}V as the gettered species, the binding of metals to P{sub 4}V satisfactorily explains the experimentally observed strong gettering behavior at high phosphorus concentrations.

Peak Phosphorus: Clarifying the Key Issues of a Vigorous Debate about Long-Term Phosphorus Security

Directory of Open Access Journals (Sweden)

Stuart White

2011-10-01

Full Text Available This paper reviews the latest information and perspectives on global phosphorus scarcity. Phosphorus is essential for food production and modern agriculture currently sources phosphorus fertilizers from finite phosphate rock. The 2008 food and phosphate fertilizer price spikes triggered increased concerns regarding the depletion timeline of phosphate rock reserves. While estimates range from 30 to 300 years and are shrouded by lack of publicly available data and substantial uncertainty, there is a general consensus that the quality and accessibility of remaining reserves are decreasing and costs will increase. This paper clarifies common sources of misunderstandings about phosphorus scarcity and identifies areas of consensus. It then asks, despite some persistent uncertainty, what would it take to achieve global phosphorus security? What would a ‘hard-landing’ response look like and how could preferred ‘soft-landing’ responses be achieved?

Effect of cobalt on microstructural parameters and mechanical properties of Ni-base single crystal superalloys

International Nuclear Information System (INIS)

Suzuki, Takanobu; Imai, Hachiro; Yokokawa, Tadaharu; Kobayashi, Toshiharu; Koizumi, Yutaka; Harada, Hiroshi

2007-01-01

The alloying effect of Cobalt (Co) to microstructural parameters and mechanical properties, such as partitioning ratios of alloying elements and creep strength, of Re-bearing Ni-base single crystal superalloys have been investigated. The second generation single crystal superalloys, TMS-82+, Ni-7.8Co-4.9Cr-1.9Mo-8.7W-5.3Al-6.0Ta-2.4Re-0.1Hf, in mass% (8Co) was compared to a Co-free (0Co) and 15 mass% Co (15Co) alloy which had the same chemical composition as TMS-82+ except that Co was changed. It was shown that the partitioning ratios of alloying elements trend to k(=X γ /X' γ )=1, as the content of Co was increased. Furthermore, it was found that there was suitable content of Co for the creep strength under various temperature-stress conditions. (author)

Effect of Crystal Orientation on Fatigue Failure of Single Crystal Nickel Base Turbine Blade Superalloys

Science.gov (United States)

Arakere, Nagaraj K.; Swanson, Gregory R.

2000-01-01

High Cycle Fatigue (HCF) induced failures in aircraft gas-turbine engines is a pervasive problem affecting a wide range of components and materials. HCF is currently the primary cause of component failures in gas turbine aircraft engines. Turbine blades in high performance aircraft and rocket engines are increasingly being made of single crystal nickel superalloys. Single-crystal Nickel-base superalloys were developed to provide superior creep, stress rupture, melt resistance and thermomechanical fatigue capabilities over polycrystalline alloys previously used in the production of turbine blades and vanes. Currently the most widely used single crystal turbine blade superalloys are PWA 1480/1493 and PWA 1484. These alloys play an important role in commercial, military and space propulsion systems. PWA1493, identical to PWA1480, but with tighter chemical constituent control, is used in the NASA SSME (Space Shuttle Main Engine) alternate turbopump, a liquid hydrogen fueled rocket engine. Objectives for this paper are motivated by the need for developing failure criteria and fatigue life evaluation procedures for high temperature single crystal components, using available fatigue data and finite element modeling of turbine blades. Using the FE (finite element) stress analysis results and the fatigue life relations developed, the effect of variation of primary and secondary crystal orientations on life is determined, at critical blade locations. The most advantageous crystal orientation for a given blade design is determined. Results presented demonstrates that control of secondary and primary crystallographic orientation has the potential to optimize blade design by increasing its resistance to fatigue crack growth without adding additional weight or cost.

Estimation of phosphorus flux in rivers during flooding.

Science.gov (United States)

Chen, Yen-Chang; Liu, Jih-Hung; Kuo, Jan-Tai; Lin, Cheng-Fang

2013-07-01

Reservoirs in Taiwan are inundated with nutrients that result in algal growth, and thus also reservoir eutrophication. Controlling the phosphorus load has always been the most crucial issue for maintaining reservoir water quality. Numerous agricultural activities, especially the production of tea in riparian areas, are conducted in watersheds in Taiwan. Nutrients from such activities, including phosphorus, are typically flushed into rivers during flooding, when over 90% of the yearly total amount of phosphorous enters reservoirs. Excessive or enhanced soil erosion from rainstorms can dramatically increase the river sediment load and the amount of particulate phosphorus flushed into rivers. When flow rates are high, particulate phosphorus is the dominant form of phosphorus, but sediment and discharge measurements are difficult during flooding, which makes estimating phosphorus flux in rivers difficult. This study determines total amounts of phosphorus transport by measuring flood discharge and phosphorous levels during flooding. Changes in particulate phosphorus, dissolved phosphorus, and their adsorption behavior during a 24-h period are analyzed owing to the fact that the time for particulate phosphorus adsorption and desorption approaching equilibrium is about 16 h. Erosion of the reservoir watershed was caused by adsorption and desorption of suspended solids in the river, a process which can be summarily described using the Lagmuir isotherm. A method for estimating the phosphorus flux in the Daiyujay Creek during Typhoon Bilis in 2006 is presented in this study. Both sediment and phosphorus are affected by the drastic discharge during flooding. Water quality data were collected during two flood events, flood in June 9, 2006 and Typhoon Bilis, to show the concentrations of suspended solids and total phosphorus during floods are much higher than normal stages. Therefore, the drastic changes of total phosphorus, particulate phosphorus, and dissolved phosphorus in

Atomic Species Associated with the Portevin-Le Chatelier Effect in Superalloy 718 Studied by Mechanical Spectroscopy

Science.gov (United States)

Max, B.; San Juan, J.; Nó, M. L.; Cloue, J. M.; Viguier, B.; Andrieu, E.

2018-06-01

In many Ni-based superalloys, dynamic strain aging (DSA) generates an inhomogeneous plastic deformation resulting in jerky flow known as the Portevin-Le Chatelier (PLC) effect. This phenomenon has a deleterious effect on the mechanical properties and, at high temperature, is related to the diffusion of substitutional solute atoms toward the core of dislocations. However, the question about the nature of the atomic species responsible for the PLC effect at high temperature still remains open. The goal of the present work is to answer this important question; to this purpose, three different 718-type and a 625 superalloy were studied through a nonconventional approach by mechanical spectroscopy. The internal friction (IF) spectra of all the studied alloys show a relaxation peak P 718 (at 885 K for 0.1 Hz) in the same temperature range, 700 K to 950 K, as the observed PLC effect. The activation parameters of this relaxation peak have been measured, E a( P 718) = 2.68 ± 0.05 eV, τ 0 = 2·10-15 ± 1 s as well as its broadening factor β = 1.1. Experiments on different alloys and the dependence of the relaxation strength on the amount of Mo attribute this relaxation to the stress-induced reorientation of Mo-Mo dipoles due to the short distance diffusion of one Mo atom by exchange with a vacancy. Then, it is concluded that Mo is the atomic species responsible for the high-temperature PLC effect in 718 superalloy.

Total phosphorus, phytate phosphorus contents and the correlation of phytates with amylose in selected edible beans in Sri Lanka

Directory of Open Access Journals (Sweden)

Keerthana Sivakumaran

2018-02-01

Full Text Available Phytate a major anti nutritional factors in legumes and it accounts for larger portion of the total phosphorus, while limiting the bioavailablity of certain divalent cations to the human body. Legumes of eleven varieties cultivated in Sri Lanka, Mung bean (MI5, MI6, Cowpea (Waruni, MICP1, Bombay, Dhawala, ANKCP1, Soybean (MISB1, Pb1 and Horse gram (ANKBlack, ANKBrown were analyzed for phosphorus content and phytate content. Total phosphorus content was quantified by dry ashing followed by spectrophotometrical measurement of the blue colour intensity of acid soluble phosphate with sodium molybdate in the presence of ascorbic acid while phytate phosphorus using anion exchange chromatographic technique followed by spectrometrical measurement of the digested organic phosphorus and amylose content by Simple Iodine-Colourimetric method. Where the least value for phosphorus was observed 275.04 ±1.44 mg.100g-1 in ANKBlack (Horse gram and the highest in MISB1 (Soyabean with 654.94 ±0.05 mg.100g-1. The phytate phosphorus content (which is a ratio of phyate to total phosphorus was highest in Dhawala (Cowpea. The phytate phosphorus (which is a ratio of phyate to total phosphorus was highest in Dhawala with 67.42% and least in Bombay (Cowpea with 24.87%. The amylose content of the legumes was least in Pb1 with 8.71 ±0.13 mg.100mg-1 and the highest in MI6 22.58 ±0.71 mg.100mg-1. The correlation between phyate and total phosphorus was significant (p <0.05 and positive (r = 0.62. Similarly the correlation coefficient for phytate phosphorus and total phosphorus was significant (p <0.05 and positive (r = 0.63. Amylose content of legumes was significantly correlated negatively (p <0.05 with the total phytates content (r = -0.82.

Potential Phosphorus Mobilisation in Peat Soils

DEFF Research Database (Denmark)

Forsmann, Ditte M.; Kjærgaard, Charlotte

2012-01-01

Re-establishment of wetlands on peat soils containing phosphorus bound to iron(III)-oxides can lead to an undesirable phosphorus loss to the aquatic environment due to the reductive dissolution of iron(III)-oxides. Thus it is important to be able to assess the potential phosphorus mobilisation from...... peat soils before a re-establishment takes place. The potential phosphorus mobilisation from a peat soil depends not only on the geochemical characteristics but also on the redox conditions, the hydrological regime in the area as well as the hydro-physical properties of the soil. The hypothesis...... for this study is (i) the release of phosphorus in peat is controlled by the geochemistry; (ii) the mobilisation of phosphorus is controlled by both geochemistry and hydro-physics of the soil. For this study, 10 Danish riparian lowland areas with peat soil were selected based on their geochemical characteristics...

Assessing the Long Term Impact of Phosphorus Fertilization on Phosphorus Loadings Using AnnAGNPS

OpenAIRE

Yuan, Yongping; Bingner, Ronald L.; Locke, Martin A.; Stafford, Jim; Theurer, Fred D.

2011-01-01

High phosphorus (P) loss from agricultural fields has been an environmental concern because of potential water quality problems in streams and lakes. To better understand the process of P loss and evaluate the effects of different phosphorus fertilization rates on phosphorus losses, the USDA Annualized AGricultural Non-Point Source (AnnAGNPS) pollutant loading model was applied to the Ohio Upper Auglaize watershed, located in the southern portion of the Maumee River Basin. In this study, the ...

Phosphorus dendrimers for nanomedicine.

Science.gov (United States)

Caminade, Anne-Marie

2017-08-31

From biomaterials to imaging, and from drug delivery to drugs by themselves, phosphorus-containing dendrimers offer a large palette of biological properties, depending essentially on their types of terminal functions. The most salient examples of phosphorus dendrimers used for the elaboration of bio-chips and of supports for cell cultures, for imaging biological events, and for carrying and delivering drugs or biomacromolecules are presented in this feature article. Several phosphorus dendrimers can be considered also as drugs per se (by themselves) in particular to fight against cancers, neurodegenerative diseases, and inflammation, both in vitro and in vivo. Toxicity assays are also reported.

Effect of mycorrhiza on growth criteria and phosphorus nutrition of lettuce (Lactuca sativa L. under different phosphorus application rates

Directory of Open Access Journals (Sweden)

S. Fatih Ergin

2016-10-01

Full Text Available In this study, effect of mycorrhiza on growth criteria and phosphorus nutrition of lettuce (Lactuca sativa L. under different phosphorus fertilization rates were investigated. Phosphorus were added into growing media as 0, 50, 100 and 200 mg P2O5/kg with and without mycorrhiza applications. Phosphorus applications significantly increased yield criteria of lettuce according to the control treatment statistically. Mycorrhiza application also significantly increased plant diameter, plant dry weight and phosphor uptake by plant. The highest phosphorus uptakes by plants were determined in 200 mg P2O5/kg treatments as 88.8 mg P/pot with mycorrhiza and 83.1 mg P/pot without mycorrhiza application. In the control at 0 doses of phosphorus with mycorrhiza treatment, phosphorus uptake (69.9 mg P/pot, edible weight (84.36 g, dry weight (8.64 g and leaf number (28 of lettuce were higher than that (47.7 mg P/pot, 59.33 g, 6.75 g and 20, respectively in the control without mycorrhiza application. It was determined that mycorrhiza had positive effect on growth criteria and phosphorus nutrition by lettuce plant, and this effect decreased at higher phosphorus application rates.

Environmental Phosphorus Recovery Based on Molecular Bioscavengers

DEFF Research Database (Denmark)

Gruber, Mathias Felix

Phosphorus is a ubiquitous element of all known life and as such it is found throughout numerous key molecules related to various cellular functions. The supply of phosphorus is tightly linked to global food security, since phosphorus is used to produce agricultural fertilizers, without which...... it would not be possible to feed the world population. Sadly, the current supply of phosphorus is based on the gradual depletion of limited fossil reserves, and some estimates predict that within 15-25 years we will consume more phosphorus than we can produce. There is therefore a strong international...... pressure to develop sustainable phosphorus practices as well as new technologies for phosphorus recovery. Nature has spent billions of years refining proteins that interact with phosphates. This has inspired the present work where the overall ambitions are: to facilitate the development of a recovery...

Strengthening of Shear Walls

DEFF Research Database (Denmark)

Hansen, Christian Skodborg

The theory for concrete structures strengthened with fiber reinforced polymer materials has been developing for approximately two decades, and there are at the present time numerous guidelines covering strengthening of many commonly encountered structural building elements. Strengthening of in...... that describes a unit width strip of a strengthened disk. The unit width strip is named a strengthened concrete tension member and contains a single tensile crack and four debonding cracks. Analysis of the member results in closed form expressions for the load-crack opening relationship. Further analysis...... of the response, results in the ability to determine and characterize the two-way crack propagation, i.e. the relationship between tensile cracking in the concrete and interface debonding between strengthening and concrete. Using the load-crack opening relationship from the strengthened concrete tension member...

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

Czech Academy of Sciences Publication Activity Database

Polák, Jaroslav; Petrenec, Martin; Chlupová, Alice; Tobiáš, Jiří; Petráš, Roman

2015-01-01

Roč. 57, č. 2 (2015), s. 119-125 ISSN 0025-5300 R&D Projects: GA ČR(CZ) GA13-23652S; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : cyclic plasticity * elevat ed temperature * superalloys * hysteresis loop * statistical theory Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.266, year: 2015

ATD and DSC Analysis of IN-713C and ZhS6U-VI Superalloys

Directory of Open Access Journals (Sweden)

Binczyk F.

2017-03-01

Full Text Available Paper presents the results of ATD and DSC analysis of two superalloys used in casting of aircraft engine parts. The main aim of the research was to obtain the solidification parameters, especially Tsol and Tliq, knowledge of which is important for proper selection of casting and heat treatment parameters. Assessment of the metallurgical quality (presence of impurities of the feed ingots is also a very important step in production of castings. It was found that some of the feed ingots delivered by the superalloy producers are contaminated by oxides located in shrinkage defects. The ATD analysis allows for quite precise interpretation of first stages of solidification at which solid phases with low values of latent heat of solidification are formed from the liquid. Using DSC analysis it is possible to measure precisely the heat values accompanying the phase changes during cooling and heating which, with knowledge of phase composition, permits to calculate the enthalpy of formation of specific phases like γ or γ′.

Enhancing the Oxidation Performance of Wrought Ni-Base Superalloy by Minor Additions of Active Elements

Science.gov (United States)

Tawancy, H. M.

2016-12-01

We show that the oxidation performance of Cr2O3-forming superalloy based upon the Ni-Cr-W system is significantly improved by the presence of minor concentrations of La, Si and Mn, which outweigh the detrimental effect of high W concentration in the alloy. Although Cr2O3 is known to transform into volatile CrO3 at temperatures ≥950 °C, the respective protection is extended to temperatures reaching 1150 °C, which has also been correlated with the beneficial effects of La, Si and Mn. During high-temperature oxidation, an inner protective La- and Si-modified layer of α-Cr2O3 in contact with the superalloy substrate is developed and shielded by an outermost layer of MnCr2O4. The distribution of La and Si in the inner oxide layer has been characterized down to the scale of transmission electron microscopy, and the possible mechanisms underlying their beneficial effects are elucidated.

Creep-rupture behavior of iron superalloys in high-pressure hydrogen

Science.gov (United States)

Bhattacharyya, S.; Peterman, W.

1984-01-01

The creep-rupture properties of five iron-base and one cobalt-base high temperature alloys were investigated to assess the feasibility of using the alloys as construction materials in a Stirling engine. The alloys were heat treated and hardness measurements were taken. Typical microstructures of the alloys are shown. The creep-rupture properties of the alloys were determined at 760 and 815 C in 15.0 MPa H2 for 200 to 1000 hours. Plots of rupture life versus stress for the six superalloys are presented along with creep strain-time plots.

Synergistic erosion/corrosion of superalloys in PFB coal combustor effluent

Science.gov (United States)

Benford, S. M.; Zellars, G. R.; Lowell, C. E.

1981-01-01

Two Ni-based superalloys were exposed to the high velocity effluent of a pressurized fluidized bed coal combustor. Targets were 15 cm diameter rotors operating at 40,000 rpm and small flat plate specimens. Above an erosion rate threshold, the targets were eroded to bare metal. The presence of accelerated oxidation at lower erosion rates suggests erosion/corrosion synergism. Various mechanisms which may contribute to the observed oxide growth enhancement include erosive removal of protective oxide layers, oxide and subsurface cracking, and chemical interaction with sulfur in the gas and deposits through damaged surface layers.

Precipitate Contribution to the Acoustic Nonlinearity in Nickel-Based Superalloy

Institute of Scientific and Technical Information of China (English)

Chung-Seok KIM; Cliff J.LISSENDEN

2009-01-01

The influence of γ' precipitate on the acoustic nonlinearity is investigated for a nickel-based superalloy,which is subjected to creep deformation.During creep deformation,the cuboidal γ' precipitate is preferentially coarsened in a direction perpendicular to the applied stress axis.The length and shape factor of the γ' precipitate increase with creep time.The increase of relative acoustic nonlinearity with increasing fraction of creep life is discussed in relation to the rafting of γ' precipitate,which is closely related to the scattering and distortion of the acoustic wave.

Thermal evolution behavior of carbides and γ′ precipitates in FGH96 superalloy powder

International Nuclear Information System (INIS)

Zhang Lin; Liu Hengsan; He Xinbo; Rafi-ud-din; Qu Xuanhui; Qin Mingli; Li Zhou; Zhang Guoqing

2012-01-01

The characteristics of rapidly solidified FGH96 superalloy powder and the thermal evolution behavior of carbides and γ′ precipitates within powder particles were investigated. It was observed that the reduction of powder size and the increase of cooling rate had transformed the solidification morphologies of atomized powder from dendrite in major to cellular structure. The secondary dendritic spacing was measured to be 1.02–2.55 μm and the corresponding cooling rates were estimated to be in the range of 1.4 × 10 4 –4.7 × 10 5 K·s −1 . An increase in the annealing temperature had rendered the phase transformation of carbides evolving from non-equilibrium MC′ carbides to intermediate transition stage of M 23 C 6 carbides, and finally to thermodynamically stable MC carbides. The superfine γ′ precipitates were formed at the dendritic boundaries of rapidly solidified superalloy powder. The coalescence, growth, and homogenization of γ' precipitates occurred with increasing annealing temperature. With decreasing cooling rate from 650 °C·K −1 to 5 °C·K −1 , the morphological development of γ′ precipitates had been shown to proceed from spheroidal to cuboidal and finally to solid state dendrites. Meanwhile, a shift had been observed from dendritic morphology to recrystallized structure between 900 °C and 1050 °C. Moreover, accelerated evolution of carbides and γ' precipitates had been facilitated by the formation of new grain boundaries which provide fast diffusion path for atomic elements. - Highlights: ► Microstructural characteristic of FGH96 superalloy powder was investigated. ► The relation between microstructure, particle size, and cooling rate was studied. ► Thermal evolution behavior of γ′ and carbides in loose FGH96 powder was studied.

Fundamental studies of electron beam welding of heat-resistant superalloys for nuclear plants, 5

International Nuclear Information System (INIS)

Arata, Yoshiaki; Terai, Kiyohide; Nagai, Hiroyoshi; Shimizu, Shigeki; Aota, Toshiichi.

1978-01-01

In this paper, the mechanical properties of base metal, its electron beam and TIG weld joint of superalloys for nuclear plants were made clear and compared with each other. As a result, it has been clarified that electron beam weld joint is superior to TIG weld joint and nearly comparable to base metal. (author)

High-cycle fatigue behavior of Co-based superalloy 9CrCo at elevated temperatures

Directory of Open Access Journals (Sweden)

Wan Aoshuang

2016-10-01

Full Text Available A modified model is developed to characterize and evaluate high-cycle fatigue behavior of Co-based superalloy 9CrCo at elevated temperatures by considering the stress ratio effect. The model is informed by the relationship surface between maximum nominal stress, stress ratio and fatigue life. New formulae are derived to deal with the test data for estimating the parameters of the proposed model. Fatigue tests are performed on Co-based superalloy 9CrCo subjected to constant amplitude loading at four stress ratios of −1, −0.3, 0.5 and 0.9 in three environments of room temperature (i.e., about 25 °C and elevated temperatures of 530 °C and 620 °C, and the interaction mechanisms between the elevated temperature and stress ratio are deduced and compared with each other from fractographic studies. Finally, the model is applied to experimental data, demonstrating the practical and effective use of the proposed model. It is shown that new model has good correlation with experimental results.

Study on Plastic Deformation Characteristics of Shot Peening of Ni-Based Superalloy GH4079

Science.gov (United States)

Zhong, L. Q.; Liang, Y. L.; Hu, H.

2017-09-01

In this paper, the X-ray stress diffractometer, surface roughness tester, field emission scanning electron microscope(SEM), dynamic ultra-small microhardness tester were used to measure the surface residual stress and roughness, topography and surface hardness changes of GH4079 superalloy, which was processed by metallographic grinding, turning, metallographic grinding +shot peening and turning + shot peening. Analysized the effects of shot peening parameters on shot peening plastic deformation features; and the effects of the surface state before shot peening on shot peening plastic deformation characteristics. Results show that: the surface residual compressive stress, surface roughness and surface hardness of GH4079 superalloy were increased by shot peening, in addition, the increment of the surface residual compressive stress, surface roughness and surface hardness induced by shot peening increased with increasing shot peening intensity, shot peening time, shot peening pressure and shot hardness, but harden layer depth was not affected considerably. The more plastic deformation degree of before shot peening surface state, the less increment of the surface residual compressive stress, surface roughness and surface hardness induced by shot peening.

Traps for phosphorus adsorption

International Nuclear Information System (INIS)

Montoya, Nawer D; Villegas, Wilson E; Rodriguez, Lino M; Taborda, Nelson; Montes de C, Consuelo

2001-01-01

Several AL 2 O 3 supported oxides such as: NiO, CuO, Co 2 O 3 BaO, CeO 2 and ZnO were investigated for phosphorus adsorption. Zno/y-Al 2 O 3 exhibited the highest phosphorus adsorption capacity. However, since it diminishes the activity of to the reaction mixture it should be located upstream of the NoX catalyst, i.e. 0,3% Pd-H-MOR, in order to protect it against p poisoning. The treatment procedure with citric acid was effective for the removal of more than 70% phosphorus from the adsorbent, ZnO/y-Al 2 O 3

Eddy Current Nondestructive Residual Stress Assessment in Shot-Peened Nickel-Base Superalloys

International Nuclear Information System (INIS)

Blodgett, M.P.; Yu, F.; Nagy, P.B.

2005-01-01

Shot peening and other mechanical surface enhancement methods improve the fatigue resistance and foreign-object damage tolerance of metallic components by introducing beneficial near-surface compressive residual stresses and hardening the surface. However, the fatigue life improvement gained via surface enhancement is not explicitly accounted for in current engine component life prediction models because of the lack of accurate and reliable nondestructive methods that could verify the presence of compressive near-surface residual stresses in shot-peened hardware. In light of its frequency-dependent penetration depth, the measurement of eddy current conductivity has been suggested as a possible means to allow the nondestructive evaluation of subsurface residual stresses in surface-treated components. This technique is based on the so-called piezoresistivity effect, i.e., the stress-dependence of electrical resistivity. We found that, in contrast with most other materials, surface-treated nickel-base superalloys exhibit an apparent increase in electrical conductivity at increasing inspection frequencies, i.e., at decreasing penetration depths. Experimental results are presented to illustrate that the excess frequency-dependent apparent eddy current conductivity of shot-peened nickel-base superalloys can be used to estimate the absolute level and penetration depth of the compressive residual stress layer both before and after partial thermal relaxation

A phenomenological creep model for nickel-base single crystal superalloys at intermediate temperatures

Science.gov (United States)

Gao, Siwen; Wollgramm, Philip; Eggeler, Gunther; Ma, Anxin; Schreuer, Jürgen; Hartmaier, Alexander

2018-07-01

For the purpose of good reproduction and prediction of creep deformation of nickel-base single crystal superalloys at intermediate temperatures, a phenomenological creep model is developed, which accounts for the typical γ/γ‧ microstructure and the individual thermally activated elementary deformation processes in different phases. The internal stresses from γ/γ‧ lattice mismatch and deformation heterogeneity are introduced through an efficient method. The strain hardening, the Orowan stress, the softening effect due to dislocation climb along γ/γ‧ interfaces and the formation of dislocation ribbons, and the Kear–Wilsdorf-lock effect as key factors in the main flow rules are formulated properly. By taking the cube slip in \\{100\\} slip systems and \\{111\\} twinning mechanisms into account, the creep behavior for [110] and [111] loading directions are well captured. Without specific interaction and evolution of dislocations, the simulations of this model achieve a good agreement with experimental creep results and reproduce temperature, stress and crystallographic orientation dependences. It can also be used as the constitutive relation at material points in finite element calculations with complex boundary conditions in various components of superalloys to predict creep behavior and local stress distributions.

Very High Cycle Fatigue of Ni-Based Single-Crystal Superalloys at High Temperature

Science.gov (United States)

Cervellon, A.; Cormier, J.; Mauget, F.; Hervier, Z.; Nadot, Y.

2018-05-01

Very high cycle fatigue (VHCF) properties at high temperature of Ni-based single-crystal (SX) superalloys and of a directionally solidified (DS) superalloy have been investigated at 20 kHz and a temperature of 1000 °C. Under fully reversed conditions (R = - 1), no noticeable difference in VHCF lifetimes between all investigated alloys has been observed. Internal casting pores size is the main VHCF lifetime-controlling factor whatever the chemical composition of the alloys. Other types of microstructural defects (eutectics, carbides), if present, may act as stress concentration sites when the number of cycles exceed 109 cycles or when porosity is absent by applying a prior hot isostatic pressing treatment. For longer tests (> 30 hours), oxidation also controls the main crack initiation sites leading to a mode I crack initiation from oxidized layer. Under such conditions, alloy's resistance to oxidation has a prominent role in controlling the VHCF. When creep damage is present at high ratios (R ≥ 0.8), creep resistance of SX/DS alloys governs VHCF lifetime. Under such high mean stress conditions, SX alloys developed to retard the initiation and creep propagation of mode I micro-cracks from pores have better VHCF lifetimes.

Phosphorus recycling from an unexplored source by polyphosphate accumulating microalgae and cyanobacteria – a step to phosphorus security in agriculture

Directory of Open Access Journals (Sweden)

Chandan eMukherjee

2015-12-01

Full Text Available Phosphorus (P, an essential element required for crop growth has no substitute. The global food security depends on phosphorus availability in soil for crop production. World phosphorus reserves are fast depleting and with an annual increase of 2.3% in phosphorus demand, the current reserves will be exhausted in coming 50-100 years. India and other Western countries are forced to import phosphorus fertilizers at high costs to meet their agricultural demands due to uneven distribution of phosphate rocks on earth. The present study from India, aims to draw attention to an unnoticed source of phosphorus being wasted as parboiled rice mill effluent and subsequent bio-recovery of the valuable element from this unconventional source. The research was conducted in West Bengal, India, a state with the highest number of parboiled rice mills where its effluent carries on an average ~40 mg/L of soluble phosphorus. Technology to recover and recycle this wastewater P in India in a simple, inexpensive mode is yet to be optimized. Our strategy to use microalgae, Chlorella sp. and cyanobacteria, Cyanobacterium sp., Lyngbya sp. and Anabaena sp. to sequester the excess phosphorus from the effluent as polyphosphate inclusions and its subsequent recycling as slow and moderate release phosphorus biofertilizers to aid plant growth, preventing phosphorus loss and pollution, is a contemporary venture to meet the need of the hour. These polyphosphate accumulating microorganisms play a dual role of remediation and recovery of phosphorus, preliminarily validated in laboratory scale.

Relative efficiency of different methods of phosphorus (32P) application on fertilizer phosphorus uptake by maize (zea may L.)

International Nuclear Information System (INIS)

Chaudhary, M.L.; Gupta, A.P.

1975-01-01

A green house study was conducted for comparing four methods of phosphorus application (broad cast, below the seed, one side and both sides of the seeds) at the rate of 60 ppm in sierozem soil of H issar (Haryana). Maize crop was planted in 50 cm. bottomless bitumin drums for 70 days i.e. upto tasseling stage. The plant samples were collected at jointing and tasseling stages of plant growth. The results revealed that the highest dry matter yield, total and fertilizer phosphorus uptake was observed when the phosphorus was applied below the seed, followed by both side application of phosphorus. The least yield, total and fertilizer phosphorus uptake were recorded when the phosphorus was broadcast at the time of sowing. (author)

Creep-fatigue of low cobalt superalloys

Science.gov (United States)

Halford, G. R.

1982-01-01

Testing for the low cycle fatigue and creep fatigue resistance of superalloys containing reduced amounts of cobalt is described. The test matrix employed involves a single high temperature appropriate for each alloy. A single total strain range, again appropriate to each alloy, is used in conducting strain controlled, low cycle, creep fatigue tests. The total strain range is based upon the level of straining that results in about 10,000 cycles to failure in a high frequency (0.5 Hz) continuous strain-cycling fatigue test. No creep is expected to occur in such a test. To bracket the influence of creep on the cyclic strain resistance, strain hold time tests with ore minute hold periods are introduced. One test per composition is conducted with the hold period in tension only, one in compression only, and one in both tension and compression. The test temperatures, alloys, and their cobalt compositions that are under study are given.

The influence of high temperature on the microstructure properties of Ni-based superalloy

Czech Academy of Sciences Publication Activity Database

Luptáková, Natália; Král, Petr; Dymáček, Petr

2014-01-01

Roč. 14, č. 4 (2014), s. 190-198 ISSN 1335-8987. [Deformation and Fracture in PM Materials. Stará Lesná, 26.10.2014-29.10.2014] R&D Projects: GA MPO FR-TI4/406; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : powder materials * Ni-based PM superalloy * grip of creep machine * oxidation Subject RIV: JG - Metallurgy

Contributions to total phosphorus intake: all sources considered.

Science.gov (United States)

Calvo, Mona S; Uribarri, Jaime

2013-01-01

High serum phosphorus is linked to poor health outcome and mortality in chronic kidney disease (CKD) patients before or after the initiation of dialysis. Dietary intake of phosphorus, a major determinant of serum phosphorus, seems to be systematically underestimated using the available software tools and generalized nutrient content databases. Several sources of dietary phosphorus including the addition of phosphorus ingredients in food processing, and phosphorus content of vitamin and mineral supplements and commonly used over-the-counter or prescription medications are not fully accounted for by the nutrient content databases and software programs in current clinical use or used in large population studies. In this review, we explore the many unknown sources of phosphorus in the food supply to identify all possible contributors to total phosphorus intake of Americans that have escaped inclusion in past intake estimates. Our goal is to help delineate areas for future interventions that will enable tighter control of dietary phosphorus intake, a critical factor to maintaining health and quality of life in CKD and dialysis patients. © 2012 Wiley Periodicals, Inc.

Influence of integrated phosphorus supply and plant growth ...

African Journals Online (AJOL)

To guarantee a sufficient phosphorus supply for plants, a rapid and permanent mobilization of phosphorus from the labile phosphorus fractions is necessary, because phosphorus concentrations in soil solution are generally low. Several plant growth-promoting rhizobacteria (PGPR) have shown potential to enhance ...

Powder metallurgy approaches to high temperature components for gas turbine engines

Science.gov (United States)

Probst, H. B.

1974-01-01

Research is reported for the tensile strength, ductility, and heat performance characterisitics of powder metallurgy (p/m) superalloys. Oxide dispersion strengthened alloys were also evaluated for their strength during thermal processing. The mechanical attributes evident in both p/m supperalloys and dispersion strengthened alloys are discussed in terms of research into their possible combination.

Phosphorus determination by various substoichiometric methods

International Nuclear Information System (INIS)

Shigematsu, Toshio; Kudo, Kiyoshi

1981-01-01

Various substoichiometric methods have been classified from a view point of the substoichiometric separation. Based upon the substoichiometric separation, phosphorus was determined substoichiometrically by a direct method, a method of carrier amount variation and a comparison method for the irradiated sample. The direct method was applied to the determination of phosphorus in orchard leaves (SRM-1571). The analytical value was 0.23 +- 0.01%. Phosphorus in orchard leaves and spinach (SRM-1570) was determined by an ordinary method which devided the sample into equal parts in the method of carrier amount variation. Analytical values of orchard leaves and spinach were 0.22 +- 0.02% and 0.56 +- 0.04%, respectively. Moreover, a new modification of the method of carrier amount variation was studied by the use of various standard samples such as red phosphorus, spinach and orchard leaves. These standard samples were also employed for the determination of phosphorus in orchard leaves and 0.21 +- 0.01% was obtained. All these results are in good agreement with the value reported by NBS. The comparison method was applied to the determination of phosphorus in a semiconductor silicon single crystal. As a result of the correction of 32 P activity induced by the secondary nuclear reaction of 30 Si, 7.9 ppb and 3.1 ppb were obtained for the phosphorus concentrations in the single crystal silicon. (author)

Looking for New Polycrystalline MC-Reinforced Cobalt-Based Superalloys Candidate to Applications at 1200°C

Directory of Open Access Journals (Sweden)

Patrice Berthod

2017-01-01

Full Text Available For applications for which temperatures higher than 1150°C can be encountered the currently best superalloys, the γ/γ′ single crystals, cannot be used under stress because of the disappearance of their reinforcing γ′ precipitates at such temperatures which are higher than their solvus. Cobalt-based alloys strengthened by refractory and highly stable carbides may represent an alternative solution. In this work the interest was focused on MC carbides of several types. Alloys were elaborated with atomically equivalent quantities in M element (among Ti, Ta, Nb, Hf, or Zr and in C. Script-like eutectic TiC, TaC, NbC, HfC, and ZrC carbides were successfully obtained in the interdendritic spaces. Unfortunately, only one type, HfC, demonstrated high morphological stability during about 50 hours at 1200°C. The concerned alloy, of the Co-25Cr-0.5C-7.4Hf type (in wt.%, was further characterized in flexural creep resistance and air-oxidation resistance at the same temperature. The creep behaviour was very good, notably by comparison with a more classical Co-25Cr-0.5C-7.5Ta alloy, proving that the interest of HfC is higher than the TaC one. In contrast the oxidation by air was faster and its behaviour not really chromia-forming. Significant improvements of this chemical resistance are expected before taking benefit from the mechanical superiority of this alloy.

Visualizing alternative phosphorus scenarios for future food security

Directory of Open Access Journals (Sweden)

Tina-Simone Neset

2016-10-01

Full Text Available The impact of global phosphorus scarcity on food security has increasingly been the focus of scientific studies over the past decade. However, systematic analyses of alternative futures for phosphorus supply and demand throughout the food system are still rare and provide limited inclusion of key stakeholders. Addressing global phosphorus scarcity requires an integrated approach exploring potential demand reduction as well as recycling opportunities. This implies recovering phosphorus from multiple sources, such as food waste, manure and excreta, as well as exploring novel opportunities to reduce the long-term demand for phosphorus in food production such as changing diets. Presently, there is a lack of stakeholder and scientific consensus around priority measures. To therefore enable exploration of multiple pathways and facilitate a stakeholder dialogue on the technical, behavioral and institutional changes required to meet long-term future phosphorus demand, this paper introduces an interactive web-based tool, designed for visualizing global phosphorus scenarios in real-time. The interactive global phosphorus scenario tool builds on several demand and supply side measures that can be selected and manipulated interactively by the user. It provides a platform to facilitate stakeholder dialogue to plan for a soft landing and identify a suite of concrete priority options, such as investing in agricultural phosphorus use efficiency, or renewable fertilizers derived from phosphorus recovered from wastewater and food waste, to determine how phosphorus demand to meet future food security could be attained on a global scale in 2040 and 2070. This paper presents four example scenarios, including (1 the potential of full recovery of human excreta, (2 the challenge of a potential increase in non-food phosphorus demand, (3 the potential of a decreased animal product consumption, and (4 the potential decrease in phosphorus demand from increased efficiency

Visualizing Alternative Phosphorus Scenarios for Future Food Security.

Science.gov (United States)

Neset, Tina-Simone; Cordell, Dana; Mohr, Steve; VanRiper, Froggi; White, Stuart

2016-01-01

The impact of global phosphorus scarcity on food security has increasingly been the focus of scientific studies over the past decade. However, systematic analyses of alternative futures for phosphorus supply and demand throughout the food system are still rare and provide limited inclusion of key stakeholders. Addressing global phosphorus scarcity requires an integrated approach exploring potential demand reduction as well as recycling opportunities. This implies recovering phosphorus from multiple sources, such as food waste, manure, and excreta, as well as exploring novel opportunities to reduce the long-term demand for phosphorus in food production such as changing diets. Presently, there is a lack of stakeholder and scientific consensus around priority measures. To therefore enable exploration of multiple pathways and facilitate a stakeholder dialog on the technical, behavioral, and institutional changes required to meet long-term future phosphorus demand, this paper introduces an interactive web-based tool, designed for visualizing global phosphorus scenarios in real time. The interactive global phosphorus scenario tool builds on several demand and supply side measures that can be selected and manipulated interactively by the user. It provides a platform to facilitate stakeholder dialog to plan for a soft landing and identify a suite of concrete priority options, such as investing in agricultural phosphorus use efficiency, or renewable fertilizers derived from phosphorus recovered from wastewater and food waste, to determine how phosphorus demand to meet future food security could be attained on a global scale in 2040 and 2070. This paper presents four example scenarios, including (1) the potential of full recovery of human excreta, (2) the challenge of a potential increase in non-food phosphorus demand, (3) the potential of decreased animal product consumption, and (4) the potential decrease in phosphorus demand from increased efficiency and yield gains in

Phosphorus K4 Crystal: A New Stable Allotrope

OpenAIRE

Jie Liu; Shunhong Zhang; Yaguang Guo; Qian Wang

2016-01-01

The intriguing properties of phosphorene motivate scientists to further explore the structures and properties of phosphorus materials. Here, we report a new allotrope named K 4 phosphorus composed of three-coordinated phosphorus atoms in non-layered structure which is not only dynamically and mechanically stable, but also possesses thermal stability comparable to that of the orthorhombic black phosphorus (A17). Due to its unique configuration, K 4 phosphorus exhibits exceptional properties: i...

Yellow phosphorus-induced Brugada phenocopy.

Science.gov (United States)

Dharanipradab, Mayakrishnan; Viswanathan, Stalin; Kumar, Gokula Raman; Krishnamurthy, Vijayalatchumy; Stanley, Daphene Divya

Metallic phosphides (of aluminum and phosphide) and yellow phosphorus are commonly used rodenticide compounds in developing countries. Toxicity of yellow phosphorus mostly pertains to the liver, kidney, heart, pancreas and the brain. Cardiotoxicity with associated Brugada ECG pattern has been reported only in poisoning with metallic phosphides. Brugada phenocopy and hepatic dysfunction were observed in a 29-year-old male following yellow phosphorus consumption. He had both type 1 (day1) and type 2 (day2) Brugada patterns in the electrocardiogram, which resolved spontaneously by the third day without hemodynamic compromise. Toxins such as aluminum and zinc phosphide have been reported to induce Brugada ECG patterns due to the generation of phosphine. We report the first case of yellow phosphorus-related Brugada phenocopy, without hemodynamic compromise or malignant arrhythmia. Copyright © 2017 Elsevier Inc. All rights reserved.

Improved cyclic oxidation resistance of electron beam physical vapor deposited nano-oxide dispersed {beta}-NiAl coatings for Hf-containing superalloy

Energy Technology Data Exchange (ETDEWEB)

Guo Hongbo [School of Materials Science and Engineering, Beihang University, No. 37, Xueyuan Road, Beijing 100191 (China); Beijing Key Laboratory for Advanced Functional Materials and Thin Film Technology, Beihang University, No. 37, Xueyuan Road, Beijing 100191 (China)], E-mail: Guo.hongbo@buaa.edu.cn; Cui Yongjing; Peng Hui; Gong Shengkai [School of Materials Science and Engineering, Beihang University, No. 37, Xueyuan Road, Beijing 100191 (China); Beijing Key Laboratory for Advanced Functional Materials and Thin Film Technology, Beihang University, No. 37, Xueyuan Road, Beijing 100191 (China)

2010-04-15

Oxide dispersed (OD) {beta}-NiAl coatings and OD-free {beta}-NiAl coatings were deposited onto a Hf-containing Ni-based superalloy by electron beam physical vapor deposition (EB-PVD). Excessive enrichment of Hf was found in the TGO on the OD-free coating due to outward diffusion of Hf from the superalloy, causing accelerated TGO thickening and spalling. The OD-coating effectively prevented Hf from outward diffusion. Only small amount of Hf diffused to the coating surface and improved the TGO adherence by virtue of the reactive element effect. The OD-coating exhibited an improved oxidation resistance as compared to the OD-free coating.

Study of the oxidation kinetics of the MA 956 superalloy

International Nuclear Information System (INIS)

Garcia-Alonso, M.C.; Gonzalez-Carrasco, J.L.; Escudero, M.L.

1998-01-01

This work deals with the oxidation kinetics of the MA 956 superalloy in the temperature range of 800-1,200 degree centigree for up to 200 h exposure. During oxidation the alloy develops a fine, compact and very well adhered α-alumina layer, the thickness of which increases with increasing time and temperature. The oxidation kinetics obeys a sub parabolic type behaviour. The scale growth seems to occur by two different oxidation mechanisms; above 1,050 degree centigree, the oxidation process would be controlled by α-alumina, and below 900 degree centigree by γ-alumina. (Author) 17 refs

Microstructural characterization of a modified 706-type Ni-Fe superalloy by small-angle neutron scattering and electron microscopy

Czech Academy of Sciences Publication Activity Database

Del Genovese, D.; Strunz, Pavel; Mukherji, D.; Gilles, R.; Rösler, J.

36A, - (2005), s. 3439-3450 ISSN 1073-5623 Institutional research plan: CEZ:AV0Z10480505 Keywords : superalloys * small-angle neutron scattering Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.232, year: 2005

Determination of phosphorus using derivative neutron activation

International Nuclear Information System (INIS)

Scindia, Y.M.; Nair, A.G.C.; Reddy, A.V.R.; Manohar, S.B.

2002-01-01

For the determination of phosphorus in different matrices, the derivative neutron activation analysis is especially applicable to aqueous samples, since the conventional neutron activation analysis is not useful for the determination of phosphorus. Phosphorus when reacted with ammonium molybdate 4 hydrate and ammonium metavanadate forms molybdo vanado phosphoric acid. This complex is preconcentrated by extracting into methyl isobutyl ketone. The organic phase containing the molybdo vanado phosphoric acid is neutron activated and the phosphorus is determined through the activation product of 52 V. Preparation of this complex, its stoichiometry, application to trace level determination of phosphorus and improved detection limit are discussed. This method was applied for the analysis of industrial effluent samples. (author)

Guiding phosphorus stewardship for multiple ecosystem services

Science.gov (United States)

Phosphorus is vital to agricultural production and water quality regulation. While the role of phosphorus in agriculture and water quality has been studied for decades, the benefits of sustainable phosphorus use and management for society due to its downstream impacts on multiple ecosystem services...

Characterization and Modeling of Microstructure Development in Nickel-base Superalloy Welds

Energy Technology Data Exchange (ETDEWEB)

Babu, S.S.; David, S.A.; Miller, M.K.; Vitek, J.M.

1999-11-01

Welding is important for economical reuse and reclamation of used and failed nickel-base superalloy blades, respectively [1]. Solidification and solid state decomposition of {gamma} (Face Centered Cubic, FCC) phase into {gamma}{prime} (L1{sub 2}-ordered) phase control the properties of these welds. In previous publications, the microstructure development in electron beam welds of PWA-1480 alloy [2] and laser beam welds of CMSX-4 alloy [3] were presented. These results showed that the weld cracking in these alloys were associated with low melting point eutectic at the dendrite boundaries [1,2]. The eutectic-{gamma}{prime} precipitation was reduced at rapid weld cooling rates and the partitioning between {gamma}-{gamma}{prime} phase was found to be far from equilibrium conditions [3,4]. This observation was related to diffusional growth of {gamma}{prime} precipitate into {gamma} phase. Subsequent to the above work, the precipitation characteristics of {gamma}{prime} phase from {gamma} phase were evaluated during continuous cooling conditions [5]. The results show that the number density of {gamma} precipitates increased with an increase in cooling rate. However, the details of this decomposition and also the fine-scale elemental partitioning characteristics between {gamma}-{gamma}{prime} were not investigated. In this paper, the precipitation characteristics of {gamma}{prime} from {gamma} during continuous cooling conditions were investigated with transmission electron microscopy, and atom probe field ion microscopy. In addition, thermodynamic and kinetic models were used to describe microstructure development in Ni-base superalloy welds.

Transformed model fitting. A straightforward approach to evaluation of anisotropic SANS from nickel-base single-crystal superalloys

International Nuclear Information System (INIS)

Strunz, P.

1999-01-01

Schematic description of a special evaluation procedure for data treatment of anisotropic Small-Angle Neutron Scattering (SANS) is presented. The use of the discussed procedure is demonstrated on a data taken from investigation of precipitation in single-crystal nickel-base superalloys. (author)

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

Impacts of anthropic pressures on soil phosphorus availability, concentration, and phosphorus forms in sediments in a Southern Brazilian watershed

Energy Technology Data Exchange (ETDEWEB)

Pellegrini, Joao Batista Rossetto; Rheinheimer dos Santos, Danilo; Goncalves, Celso Santos; Copetti, Andre Carlos Cruz [Dept. de Solos, Univ. Federal de Santa Maria, Centro de Ciencias Rurais, Santa Maria, RS (Brazil); Bortoluzzi, Edson Campanhola [Faculdade de Agronomia e Medicina Veterinaria da Univ. de Passo Fundo, RS (Brazil); Tessier, Daniel [Inst. National de la Recherche Agronomique, Versailles (France)

2010-04-15

Purpose: The transfer of soil sediments and phosphorus from terrestrial to aquatic systems is a common process in agricultural lands. The aims of this paper are to quantify the soil phosphorus availability and to characterize phosphorus forms in soil sediments as contaminant agents of waters as a function of anthropic pressures. Materials and methods On three subwatersheds with different anthropic pressure, water and sediment samples were collected automatically in upstream and downstream discharge points in six rainfall events during the tobacco growing season. Phosphorus desorption capacity from soil sediments was estimated by successive extractions with anion exchange resins. First-order kinetic models were adjusted to desorption curves for estimating potentially bioavailable particulate phosphorus, desorption rate constant, and bioavailable particulate phosphorus. Results and discussion The amount of bioavailable particulate phosphorus was directly correlated with the iron oxide content. The value of desorption rate constant was directly related with the total organic carbon and inversely with the iron oxide contents. Phosphate ions were released to solution, on average, twice as rapidly from sediments collected in subwatersheds with low anthropic activity than from those ones of highly anthropic subwatersheds. Anthropic pressure on watershed can engender high sediment discharge, but these solid particles seem to present low phosphorus-releasing capacity to water during transport due to the evidenced high affinity between phosphorus and iron oxide from sediments. Conclusions Anthropic pressure was related with sediment concentration and phosphorus release to aquatic systems. While natural vegetation along streams plays a role on soil and water depuration, it is unable to eliminate the phosphorus inputs intrinsic to the agricultural-intensive systems. Recommendations and perspectives The contamination of water in watershed by phosphates is facilitated by the

Phosphorus-containing macrocyclic compounds: synthesis and properties

International Nuclear Information System (INIS)

Knyazeva, I R; Burilov, Alexander R; Pudovik, Michael A; Habicher, Wolf D

2013-01-01

Main trends in the development of methods for the synthesis of phosphorus-containing macrocyclic compounds in the past 15 years are considered. Emphasis is given to reactions producing macrocyclic structures with the participation of a phosphorus atom and other functional groups involved in organophosphorus molecules and to modifications of macrocycles by phosphorus compounds in different valence states. Possibilities of the practical application of phosphorus-containing macrocyclic compounds in difference areas of science and engineering are discussed. The bibliography includes 205 references.

Anthropogenic phosphorus flow analysis of Hefei City, China

International Nuclear Information System (INIS)

Li Sisi; Yuan Zengwei; Bi Jun; Wu Huijun

2010-01-01

The substance flow analysis (SFA) method was employed to examine phosphorus flow and its connection to water pollution in the city of Hefei, China, in 2008. As human activity is the driving force of phosphorus flux from the environment to the economy, the study provides a conceptual framework for analyzing an anthropogenic phosphorus cycle that includes four stages: extraction, fabrication and manufacturing, use, and waste management. Estimates of phosphorus flow were based on existing data as well as field research, expert advice, local accounting systems, and literature. The total phosphorus input into Hefei in 2008 reached 7810 tons, mainly as phosphate ore, chemical fertilizer, pesticides, crops and animal products. Approximately 33% of the total phosphorus input left the area, and nearly 20% of that amount was discharged as waste to surface water. Effluent containing excessive fertilizer from farming operations plays an important role in phosphorus overloads onto surface water; the other major emission source is sewage discharge. We also provide suggestions for reducing phosphorus emissions, for example reducing fertilizer use, recycling farming residues, and changing human consumption patterns.

Biological phosphorus uptake under anoxic and aerobic conditions

DEFF Research Database (Denmark)

Kerrn-Jespersen, Jens Peter; Henze, Mogens

1993-01-01

Biological phosphorus removal was investigated under anoxic and aerobic conditions. Tests were made to establish whether phosphorus accumulating bacteria can take up phosphate under anoxic conditions and thus utilise nitrate as oxidant. Furthermore, it was tested how the amount of organic matter...... as oxidant. The phosphorus uptake was more rapid under aerobic conditions than under anoxic conditions. The explanation of this is that all phosphorus accumulating bacteria take up phosphate under aerobic conditions, whereas only part of the phosphorus accumulating bacteria take up phosphate under anoxic...

Prediction of recrystallisation in single crystal nickel-based superalloys during investment casting

Directory of Open Access Journals (Sweden)

Panwisawas Chinnapat

2014-01-01

Full Text Available Production of gas turbines for jet propulsion and power generation requires the manufacture of turbine blades from single crystal nickel-based superalloys, most typically using investment casting. During the necessary subsequent solution heat treatment, the formation of recrystallised grains can occur. The introduction of grain boundaries into a single crystal component is potentially detrimental to performance, and therefore manufacturing processes and/or component geometries should be designed to prevent their occurrence. If the boundaries have very low strength, they can degrade the creep and fatigue properties. The root cause for recrystallisation is microscale plasticity caused by differential thermal contraction of metal, mould and core; when the plastic deformation is sufficiently large, recrystallisation takes place. In this work, numerical and thermo-mechanical modelling is carried out, with the aim of establishing computational methods by which recrystallisation during the heat treatment of single crystal nickel-based superalloys can be predicted and prevented prior to their occurrence. Elasto-plastic law is used to predict the plastic strain necessary for recrystallisation. The modelling result shows that recrystallisation is most likely to occur following 1.5–2.5% plastic strain applied at temperatures between 1000 ∘C and 1300 ∘C; this is validated with tensile tests at these elevated temperatures. This emphasises that high temperature deformation is more damaging than low temperature deformation.

Spray forming and mechanical properties of a new type powder metallurgy superalloy

International Nuclear Information System (INIS)

Jia Chong-Lin; Ge Chang-Chun; Xia Min; Gu Tian-Fu

2015-01-01

The deposited billet of a new type powder metallurgy (PM) superalloy FGH4095M for use in turbine disk manufacturing has been fabricated using spray forming technology. The metallurgical quality of the deposited billet was analyzed in terms of density, texture, and grain size. Comparative research was done on the microstructure and mechanical properties between the flat disk preform prepared with hot isostatic pressing (HIP) and the same alloy forgings prepared with HIP followed by isothermal forging (IF). The results show that the density of the spray-formed and nitrogen-atomized deposit billet is above 99% of the theoretical density, indicating a compact structure. The grains are uniform and fine. The billet has weak texture with a random distribution in the spray deposition direction and perpendicular to the direction of deposition. A part of atomizing nitrogen exists in the preform in the form of carbonitride. Nitrogen-induced microporosity causes the density reduction of the preform. Compared with the process of HIP+IF, the superalloy FGH4095M after HIP has better mechanical properties at both room temperature and high temperature. The sizes of the γ′ phase are finer in microstructure of the preform after HIP in comparison with the forgings after HIP+IF. This work shows that SF+HIP is a viable processing route for FGH4095M as a turbine-disk material. (paper)

Phosphorus kinetics in ovine fed with different phosphorus sources, using the isotopic dilution technique

International Nuclear Information System (INIS)

Vitti, D.M.S.S.; Abdalla, A.L.; Meirelles, C.F.

1992-01-01

Phosphorus kinetics in fluids and tissues of sheep was studied. Sixteen castrated sheep were kept in metabolism cages, receiving a semipuried diet containing as phosphorus sources dicalcium phosphate (BIC), monoammonium phosphate (MAP), superphosphate (SPT) and Tapita phosphate (TAP) 200 μCi P-32 was intravenously injected in each sheep and blood and feces were collected for eight days. From the specific activities in feces and plasma the endogenous phosphorus and the absorption coefficient were calculated. plasma P-32 half-life was determined. Nine days after injection the animals were killed and liver, kidney and muscle and bone samples were collected. P-32 retention and specific activities in tissues were determined. Endogenous phosphorus and absorption coefficient values were 54.44 ± 15.31 mh/kg live weight and 0.60; 47.98 ± 12.44 and 0.56; 39.70 ± 7.29 and 0.49; 59.11 ± 17.12 and 0.58 respectively bor BIC, MAP, TAP and SPT. P-32 retention by tissues was 0.29 ± 0.09; 0.27 ± 0.06; 0.16 ± 0.04 and 0.08 ± 0.03 dose/g fresh matter, respectively for bone, liver, kidney and muscle. It was concluded that animals which received TAP showed differences in absorption, distribution and P-32 retention by fluids and tissues. Phosphorus availability was lower for this source. (author)

Role of tantalum in the hot corrosion of a Ni-base single crystal superalloy

International Nuclear Information System (INIS)

Chang, J.X.; Wang, D.; Liu, T.; Zhang, G.; Lou, L.H.; Zhang, J.

2015-01-01

Highlights: • Ta is beneficial to hot corrosion resistance. • Ta promoted the formation of a new type sulphide TaS 2 . • Thermodynamic factors affect the constituent of sulphide layer. • Ta can substitute Cr for sulphur catcher in hot corrosion. • The result provides new perspective in hot corrosion resistant superalloys design. - Abstract: Hot corrosion behaviour of a Ni-base single crystal superalloy with low Cr, Ti and high Ta contents in molten sodium sulphate (Na 2 SO 4 ) at 900 °C in static air was investigated using the “deposit recoat” method. The corrosion scale was composed of an outer NiO layer, an inner Al 2 O 3 -dominant oxide network layer and a (CrS x(1.000

The Formation and Evolution of Shear Bands in Plane Strain Compressed Nickel-Base Superalloy

Directory of Open Access Journals (Sweden)

Bin Tang

2018-02-01

Full Text Available The formation and evolution of shear bands in Inconel 718 nickel-base superalloy under plane strain compression was investigated in the present work. It is found that the propagation of shear bands under plane strain compression is more intense in comparison with conventional uniaxial compression. The morphology of shear bands was identified to generally fall into two categories: in “S” shape at severe conditions (low temperatures and high strain rates and “X” shape at mild conditions (high temperatures and low strain rates. However, uniform deformation at the mesoscale without shear bands was also obtained by compressing at 1050 °C/0.001 s−1. By using the finite element method (FEM, the formation mechanism of the shear bands in the present study was explored for the special deformation mode of plane strain compression. Furthermore, the effect of processing parameters, i.e., strain rate and temperature, on the morphology and evolution of shear bands was discussed following a phenomenological approach. The plane strain compression attempt in the present work yields important information for processing parameters optimization and failure prediction under plane strain loading conditions of the Inconel 718 superalloy.

Improvement of stress-rupture property by Cr addition in Ni-based single crystal superalloys

International Nuclear Information System (INIS)

Chen, J.Y.; Feng, Q.; Cao, L.M.; Sun, Z.Q.

2011-01-01

Research highlights: → Cr improved the stress-rupture life of single crystal superalloys significantly. → Cr increased the Re partitioning ratio and resulted in more negative misfit. → Mechanism for improving the stress-rupture life by Cr addition is addressed here. - Abstract: The effects of Cr addition on the microstructure and stress-rupture property have been investigated in three experimental Ni-based single crystal superalloys containing various levels of Cr addition (0-5.7 wt.%). The Re partitioning ratio increased and the lattice misfit became more negative with increasing the Cr addition in both dendrite core and interdendritic region. The changes of elemental partitioning behaviors and the lattice misfit show good agreement with the change of γ' morphology. Cr addition increased the stress-rupture life at 1100 deg. C/140 MPa significantly due to higher γ' volume fraction, more negative lattice misfit and a well rafting structure as well as less width of γ channels. High Cr addition (5.7 wt.%) increased the degree of Re and Cr supersaturation in the γ phase and promoted the formation of topologically close-packed (TCP) phases significantly under thermal exposure and creep deformation at 1100 deg. C.

Effect of HIP Combined with RHT Process on Creep Damage of DZ125 Superalloy

Directory of Open Access Journals (Sweden)

WANG Tian-you

2017-02-01

Full Text Available Four different processes of hot isostatic pressing (HIP combined with rejuvenation heat treatments (RHT were adopted to reveal the microstructural evolution of creep damaged DZ125 specimens, finally the mechanical properties were evaluated.The results show that both γ' precipitate degeneration and creep cavities for the creep damaged DZ125 superalloy are found after the pre-endurance damage test.However, the carbided compositions from MC type to M23C6 type or M6C type has not been observed for DZ125.In addition, it is found that the HIP temperature play a dominant role in the cavity healing process for the damaged specimens. The concentrically oriented γ' rafting structure and the incipient melting are observed at 1200℃ and 1250℃ respectively.Meanwhile, it is found that the appropriate HIP schedule adopted can effectively avoid the internal recrystallization for the directionally solidified nickel-based superalloy DZ125. The appropriate HIP schedule combined with RHT process can successfully restore the microstructure induced by creep damage and recover the degraded micro-hardness to the original one, in addition improve the creep rupture life.

Estimate of dietary phosphorus intake using 24-h urine collection

Science.gov (United States)

Morimoto, Yuuka; Sakuma, Masae; Ohta, Hiroyuki; Suzuki, Akitsu; Matsushita, Asami; Umeda, Minako; Ishikawa, Makoto; Taketani, Yutaka; Takeda, Eiji; Arai, Hidekazu

2014-01-01

Increases in serum phosphorus levels and dietary phosphorus intake induces vascular calcification, arterial sclerosis and cardiovascular diseases. Limiting phosphorus intake is advisable, however, no assessment methods are capable of estimating dietary phosphorus intake. We hypothesized that urinary phosphorus excretion can be translated into estimation of dietary phosphorus intake, and we evaluated whether a 24-h urine collection method could estimate dietary phosphorus intake. Thirty two healthy subjects were recruited for this study. Subjects collected urine samples over 24 h and weighed dietary records. We calculated dietary protein intake and phosphorus intake from dietary records and urine collection, and investigated associations between the two methods in estimating protein and phosphorus intake. Significant positive correlations were observed between dietary records and UC for protein and phosphorus intake. The average intakes determined from dietary records were significantly higher than from urine collection for both protein and phosphorus. There was a significant positive correlation between both the phosphorus and protein difference in dietary records and urine collection. The phosphorus-protein ratio in urine collection was significantly higher than in dietary records. Our data indicated that the 24-h urine collection method can estimate the amount of dietary phosphorus intake, and the results were superior to estimation by weighed dietary record. PMID:25120281

Deformation-phase transformation coupling mechanism of white layer formation in high speed machining of FGH95 Ni-based superalloy

Energy Technology Data Exchange (ETDEWEB)

Du, Jin [School of Mechanical and Automotive Engineering, Qilu University of Technology, Jinan, Shandong 250353 (China); Liu, Zhanqiang, E-mail: melius@sdu.edu.cn [School of Mechanical Engineering, Shandong University, Jinan, Shandong 250061 (China); Key Laboratory of High Efficiency and Clean Mechanical Manufacture, Shandong University, Ministry of Education, Shandong (China); Lv, Shaoyu [School of Mechanical Engineering, Shandong University, Jinan, Shandong 250061 (China)

2014-02-15

Ni-based superalloy represents a significant metal portion of the aircraft critical structural and engine components. When these critical structural components in aerospace industry are manufactured with the objective to reach high reliability levels and excellent service performance, surface integrity is one of the most relevant parameter used for evaluating the quality of finish machined surfaces. In the study of surface integrity, the formation white layer is a very important research topic. The formation of white layer on the Ni-based superalloy machined surface will reduce the machined parts service performance and fatigue life. This paper was conducted to determine the effects of cutting speed on white layer formation in high speed machining of FGH95 Ni-based superalloy. Optical microscope, scanning electron microscope and X-ray diffraction were employed to analyze the elements and microstructures of white layer and bulk materials. The statistical analysis for grain numbers was executed to study the influence of cutting speed on the grain refinement in the machined surface. The investigation results showed that white layer exhibits significantly different microstructures with the bulk materials. It shows densification, no obvious structural features characteristic. The microstructure and phase of Ni-based solid solution changed during cutting process. The increase of cutting speed causes the increase of white layer thickness when the cutting speed is less than 2000 m/min. However, white layer thickness reduces with the cutting speed further increase. The higher the cutting speed, the more serious grains refinement in machined surface. 2-D FEM for machining FGH95 were carried out to simulate the cutting process and obtained the cutting temperature field, cutting strain field and strain rate field. The impact mechanisms of cutting temperature, cutting strain and strain rates on white layer formation were analyzed. At last, deformation-phase transformation

Low-cycle fatigue and damage of an uncoated and coated single crystal nickel-base superalloy SCB

International Nuclear Information System (INIS)

Stekovic, S.; Ericsson, T.

2007-01-01

This paper presents low-cycle fatigue (LCF) behaviour and damage mechanisms of uncoated and coated specimens of a single crystal nickel-base superalloy SCB tested at 500 C and 900 C. Four coatings were deposited on the base material, an overlay coating AMDRY997, a platinum-modified aluminide diffusion coating RT22 and two innovative coatings called IC1 and IC3 with a NiW diffusion barrier in the interface. AMDRY997 and RT22 were used as reference coatings. The LCF tests were performed at three strain amplitudes, 1.0, 1.2 and 1.4%, with R = -1, in laboratory air and without any dwell time. The LCF life of the specimens is determined by crack initiation and propagation. Crack data are presented for different classes of crack size in the form of crack density, that is, the number of cracks normalised to the investigated interface length. Micrographs of damage of the coatings are also shown. The effect of the coatings on the LCF life of the superalloy was dependent on the test temperature and deposited coating. At 500 C all coatings had a detrimental effect on the LCF life of the superalloy. At 900 C both AMDRY997 and IC1 prolonged the fatigue life of the superalloy by factors ranging between 1.5 and 4 while RT22 and IC3 shortened the life of the coating-substrate system. Specimens coated with RT22 exhibited generally more damage than other tested coatings at 900 C. Most of the cracks observed initiated at the coating surface and a majority were arrested in the interdiffusion zone between the base material and the coating. No topologically close-packed phases were found. Delamination was only found in AMDRY997 at higher strains. Surface roughness or rumpling was found in the overlay coating AMDRY997 with some cracks initiating from the rumples. The failure morphology at 900 C reflected the role of oxidation in the fatigue life, the crack initiation and propagation of the coated specimens. The wake of the cracks grown into the substrate was severely oxidised leading to

CYCLIC STRAIN LOCALIZATION IN CAST NICKEL BASED SUPERALLOY INCONEL 792-5A AT ROOM TEMPERATURE

Czech Academy of Sciences Publication Activity Database

Petrenec, Martin; Man, Jiří; Obrtlík, Karel; Polák, Jaroslav

308/2005, č. 86 (2005), s. 269-274 ISSN 1429-6055. [Metody oceny struktury oraz wlasności materialów i wyrobów. Ustroń-Jaszowiec, 07.12.2005-09.12.2005] Institutional research plan: CEZ:AV0Z20410507 Keywords : low cycle fatigue * superalloy * cyclic strain localization Subject RIV: JL - Materials Fatigue, Friction Mechanics

Phosphorus run-off assessment in a watershed.

Science.gov (United States)

Chebud, Yirgalem; Naja, Ghinwa M; Rivero, Rosanna

2011-01-01

The Watershed Assessment Model was used to simulate the runoff volume, peak flows, and non-point source phosphorus loadings from the 5870 km(2) Lake Okeechobee watershed as a case study. The results were compared to on-site monitoring to verify the accuracy of the method and to estimate the observed/simulated error. In 2008, the total simulated phosphorus contribution was 9634, 6524 and 3908 kg (P) y(-1) from sod farms, citrus farms and row crop farmlands, respectively. Although the dairies represent less than 1% of the total area of Kissimmee basin, the simulated P load from the dairies (9283 kg (P) y(-1) in 2008) made up 5.4% of the total P load during 2008. On average, the modeled P yield rates from dairies, sod farms and row crop farmlands are 3.85, 2.01 and 0.86 kg (P) ha(-1) y(-1), respectively. The maximum sediment simulated phosphorus yield rate is about 2 kg (P) ha(-1) and the particulate simulated phosphorus contribution from urban, improved pastures and dairies to the total phosphorus load was estimated at 9%, 3.5%, and 1%, respectively. Land parcels with P oversaturated soil as well as the land parcels with high phosphorus assimilation and high total phosphorus contribution were located. The most critical sub-basin was identified for eventual targeting by enforced agricultural best management practices. Phosphorus load, including stream assimilation, incoming to Lake Okeechobee from two selected dairies was also determined.

Sustainable use of phosphorus: a finite resource.

Science.gov (United States)

Scholz, Roland W; Ulrich, Andrea E; Eilittä, Marjatta; Roy, Amit

2013-09-01

Phosphorus is an essential element of life and of the modern agricultural system. Today, science, policy, agro-industry and other stakeholder groups are increasingly concerned about the sustainable use of this resource, given the dissipative nature of phosphorus and difficulties in assessing, evaluating, and coping with phosphorus pollution in aquatic and terrestrial systems. We argue that predictions about a forthcoming peak, followed by a quick reduction (i.e., physical phosphate rock scarcity) are unreasoned and stress that access to phosphorus (economic scarcity) is already, and may increasingly become critical, in particular for smallholders farmers in different parts of the world. The paper elaborates on the design, development, goals and cutting-edge contributions of a global transdisciplinary process (i.e. mutual learning between science and society including multiple stakeholders) on the understanding of potential contributions and risks related to the current mode of using phosphorus on multiple scales (Global TraPs). While taking a global and comprehensive view on the whole phosphorus-supply chain, Global TraPs organizes and integrates multiple transdisciplinary case studies to better answer questions which inform sustainable future phosphorus use. Its major goals are to contribute to four issues central to sustainable resource management: i) long-term management of biogeochemical cycles, in particular the challenge of closing the phosphorus cycle, ii) achieving food security, iii) avoiding environmental pollution and iv) sustainability learning on a global level by transdisciplinary processes. Copyright © 2013 Elsevier B.V. All rights reserved.

Mechanical behavior of superalloys

International Nuclear Information System (INIS)

Floreen, S.

1986-04-01

Recent developments affecting the mechanical behavior of superalloys over three ranges of operating temperatures are reviewed. At lower temperatures, activity has been focused on stress corrosion cracking susceptibility in light water reactor and sour gas well environments. The susceptibility to intergranular crack growth is critically dependent upon the grain boundary chemistry, and a method of minimizing the sensitivity of the boundaries to attack has been pursued. At intermediate temperatures, considerable effort has been directed toward increasing the tensile and fatigue strengths. The higher strength materials, however, show increased fracture sensitivity. In particular, embrittlement due to diffusion into the grain boundaries of aggressive species, such as oxygen or sulfur from the environments, becomes a problem. Minor element alloying additions of boron, zirconium, magnesium, etc., are helpful in retarding the degradation caused by the environment. At higher temperatures, the major thrust is toward improving the creep strength. The weak link in the materials, which is the transverse grain boundaries, has been eliminated by the use of specialized processing steps to produce either directionally solidified materials with minimum transverse grain boundaries, or single crystal materials. Single crystal materials permit alloying and heat treating modifications that further enhance the creep strength. The materials are very anisotropic in properties, but are successfully used in turbine blades and could be useful in other special applications

Towards a closed phosphorus cycle

NARCIS (Netherlands)

Keyzer, M.A.

2010-01-01

Summary: This paper stresses the need to address upcoming scarcity of phosphorus, a mineral nutrient that is essential for all life on Earth. Agricultural crops obtain phosphorus from the pool in the soil that can be replenished by recycling of organic material, or by application of inorganic

STABILITY ANALYSIS OF RADIAL TURNING PROCESS FOR SUPERALLOYS

Directory of Open Access Journals (Sweden)

Alberto JIMÉNEZ

2017-07-01

Full Text Available Stability detection in machining processes is an essential component for the design of efficient machining processes. Automatic methods are able to determine when instability is happening and prevent possible machine failures. In this work a variety of methods are proposed for detecting stability anomalies based on the measured forces in the radial turning process of superalloys. Two different methods are proposed to determine instabilities. Each one is tested on real data obtained in the machining of Waspalloy, Haynes 282 and Inconel 718. Experimental data, in both Conventional and High Pressure Coolant (HPC environments, are set in four different states depending on materials grain size and Hard-ness (LGA, LGS, SGA and SGS. Results reveal that PCA method is useful for visualization of the process and detection of anomalies in online processes.

Anthropogenic phosphorus flow analysis of Hefei City, China.

Science.gov (United States)

Li, Sisi; Yuan, Zengwei; Bi, Jun; Wu, Huijun

2010-11-01

The substance flow analysis (SFA) method was employed to examine phosphorus flow and its connection to water pollution in the city of Hefei, China, in 2008. As human activity is the driving force of phosphorus flux from the environment to the economy, the study provides a conceptual framework for analyzing an anthropogenic phosphorus cycle that includes four stages: extraction, fabrication and manufacturing, use, and waste management. Estimates of phosphorus flow were based on existing data as well as field research, expert advice, local accounting systems, and literature. The total phosphorus input into Hefei in 2008 reached 7810 tons, mainly as phosphate ore, chemical fertilizer, pesticides, crops and animal products. Approximately 33% of the total phosphorus input left the area, and nearly 20% of that amount was discharged as waste to surface water. Effluent containing excessive fertilizer from farming operations plays an important role in phosphorus overloads onto surface water; the other major emission source is sewage discharge. We also provide suggestions for reducing phosphorus emissions, for example reducing fertilizer use, recycling farming residues, and changing human consumption patterns. Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.

Transformation of apatite phosphorus and non-apatite inorganic phosphorus during incineration of sewage sludge.

Science.gov (United States)

Li, Rundong; Zhang, Ziheng; Li, Yanlong; Teng, Wenchao; Wang, Weiyun; Yang, Tianhua

2015-12-01

The recovery of phosphorus from incinerated sewage sludge ash (SSA) is assumed to be economical. Transformation from non-apatite inorganic phosphorus (NAIP) to apatite phosphorus (AP), which has a higher bioavailability and more extensive industrial applications, was studied at 750-950°C by sewage sludge incineration and model compound incineration with a calcium oxide (CaO) additive. Thermogravimetric differential scanning calorimetry analysis and X-ray diffraction measurements were used to analyze the reactions between NAIP with CaO and crystallized phases in SSA. High temperatures stimulated the volatilization of NAIP instead of AP. Sewage sludge incineration with CaO transformed NAIP into AP, and the percentage of AP from the total phosphorus reached 99% at 950°C. Aluminum phosphate reacted with CaO, forming Ca2P2O7 and Ca3(PO4)2 at 750-950°C. Reactions between iron phosphate and CaO occurred at lower temperatures, forming Ca(PO3)2 before reaching 850°C. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Research progress on phosphorus budgets and regulations in reservoirs].

Science.gov (United States)

Shen, Xiao; Li, Xu; Zhang, Wang-shou

2014-12-01

Phosphorus is an important limiting factor of water eutrophication. A clear understanding of its budget and regulated method is fundamental for reservoir ecological health. In order to pro- mote systematic research further and improve phosphorus regulation system, the budget balance of reservoir phosphorus and its influencing factors were concluded, as well as conventional regulation and control measures. In general, the main phosphorus sources of reservoirs include upstream input, overland runoff, industrial and domestic wastewater, aquaculture, atmospheric deposition and sediment release. Upstream input is the largest phosphorus source among them. The principal output path of phosphorus is the flood discharge, the emission load of which is mainly influenced by drainage patterns. In addition, biological harvest also can export a fraction of phosphorus. There are some factors affecting the reservoir phosphorus balance, including reservoirs' function, hydrological conditions, physical and chemical properties of water, etc. Therefore, the phosphorus budgets of different reservoirs vary greatly, according to different seasons and regions. In order to reduce the phosphorus loading in reservoirs, some methods are carried out, including constructed wetlands, prefix reservoir, sediment dredging, biomanipulation, etc. Different methods need to be chosen and combined according to different reservoirs' characteristics and water quality management goals. Thus, in the future research, it is reasonable to highlight reservoir ecological characteristics and proceed to a complete and systematic analysis of the inherent complexity of phosphorus budget and its impact factors for the reservoirs' management. Besides, the interaction between phosphorus budget and other nutrients in reservoirs also needs to be conducted. It is fundamental to reduce the reservoirs' phosphorus loading to establish a scientific and improved management system based on those researches.

The New Nordic Diet: phosphorus content and absorption.

Science.gov (United States)

Salomo, Louise; Poulsen, Sanne K; Rix, Marianne; Kamper, Anne-Lise; Larsen, Thomas M; Astrup, Arne

2016-04-01

High phosphorus content in the diet may have adverse effect on cardiovascular health. We investigated whether the New Nordic Diet (NND), based mainly on local, organic and less processed food and large amounts of fruit, vegetables, wholegrain and fish, versus an Average Danish Diet (ADD) would reduce the phosphorus load due to less phosphorus-containing food additives, animal protein and more plant-based proteins. Phosphorus and creatinine were measured in plasma and urine at baseline, week 12 and week 26 in 132 centrally obese subjects with normal renal function as part of a post hoc analysis of data acquired from a 26-week controlled trial. We used the fractional phosphorus excretion as a measurement of phosphorus absorption. Mean baseline fractional phosphorus excretion was 20.9 ± 6.6 % in the NND group (n = 82) and 20.8 ± 5.5 % in the ADD group (n = 50) and was decreased by 2.8 ± 5.1 and 3.1 ± 5.4 %, respectively, (p = 0.6) at week 26. At week 26, the mean change in plasma phosphorus was 0.04 ± 0.12 mmol/L in the NND group and -0.03 ± 0.13 mmol/L in the ADD group (p = 0.001). Mean baseline phosphorus intake was 1950 ± 16 mg/10 MJ in the NND group and 1968 ± 22 mg/10 MJ in the ADD group and decreased less in the NND compared to the ADD (67 ± 36 mg/10 MJ and -266 ± 45 mg/day, respectively, p food concept beneficial regarding phosphorus absorption.

Adaptive Evolution of Phosphorus Metabolism in Prochlorococcus

DEFF Research Database (Denmark)

Casey, John R; Mardinoglu, Adil; Nielsen, Jens

2016-01-01

Inorganic phosphorus is scarce in the eastern Mediterranean Sea, where the high-light-adapted ecotype HLI of the marine picocyanobacterium Prochlorococcus marinus thrives. Physiological and regulatory control of phosphorus acquisition and partitioning has been observed in HLI both in culture...... and in the field; however, the optimization of phosphorus metabolism and associated gains for its phosphorus-limited-growth (PLG) phenotype have not been studied. Here, we reconstructed a genome-scale metabolic network of the HLI axenic strain MED4 (iJC568), consisting of 568 metabolic genes in relation to 794...... through drastic depletion of phosphorus-containing biomass components but also through network-wide reductions in phosphate-reaction participation and the loss of a key enzyme, succinate dehydrogenase. These alterations occur despite the stringency of having relatively few pathway redundancies...

Phosphorus effect on fracture properties of structural steels

International Nuclear Information System (INIS)

Goritskij, V.M.; Guseva, I.A.

1985-01-01

Phosphorus content is studied for its effect on fracture peculiarities and fracture toughness. It is supposed that the phosphorus effect on ductile fractures is associated with phosphorus segregation on the ferrite-carbide interfaces. An increase of the phosphorus content in heat-treated 10KhSND steel from 0.020 up to 0.043 wt.% results in a decrease of the pore size and asub(p) value. Close linear correlation is established between critical temperature of embrittlement T 50 and √ asub(p) or √ KC values for a number of structural steels with different phosphorus content

Sustainable Phosphorus Chemistry: A Silylphosphide Synthon for the Generation of Value-Added Phosphorus Chemicals.

Science.gov (United States)

Slootweg, J Chris

2018-05-07

Avoiding white phosphorus: Cummins and Geeson have recently described the conversion of phosphoric acid into the novel bis(trichlorosilyl)phosphide anion, which serves as a key intermediate in the synthesis of organophosphines, hexafluorophosphate, and phosphine gas in a reaction sequence that does not rely on white phosphorus. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Focused Ion Beam Nanotomography of ruthenium-bearing nickel-base superalloys with focus on cast-microstructure and phase stability

International Nuclear Information System (INIS)

Cenanovic, Samir

2012-01-01

The influence of rhenium and ruthenium on the multi component system nickel-base superalloy is manifold and complex. An experimental nickel-base superalloy containing rhenium and ruthenium within defined contents, named Astra, was used to investigate the influences of these two elements on the alloy system. The last stage solidification of nickel-base superalloys after Bridgman casting and the high temperature phase stability of these alloys, could be explored with the aid of focused ion beam nanotomography. FIB-nt therefore was introduced and realized at the chair of General Materials Properties of the University Erlangen-Nuremberg. Cast Astra alloys are like other nickel-base superalloys morphologically very inhomogeneous and affected by segregation. In the interdendritic region different structures with huge γ' precipitates are formed. These inhomogeneities and remaining eutectics degrade the mechanical properties, witch makes an understanding of the subsiding processes at solidification of residual melt important for the casting process and the heat treatment. This is why the last stage solidification in the interdendritic region was analyzed. With the help of focused ion beam nanotomography, three different structures identified from 2-D sections could be assigned to one original 3-D structure. It was pointed out, that only the orientation of the plane of the 2-D cut influences the appearance in the 2-D section. The tomography information was used to explain the development during solidification and to create a model of last stage solidification. The interdendritic region is solidifying under the development of eutectic islands. The structure nucleates eutectically epitaxially at primary dendrite arms, with formation of fine γ/γ' precipitates. During solidification the γ' precipitates coarsen in a rod-like structure, and end up in large γ' precipitates. Simulations and other investigations could approve this model. First three

Influence of dwell times on the thermomechanical fatigue behavior of a directionally solidified Ni-base superalloy

Czech Academy of Sciences Publication Activity Database

Guth, S.; Petráš, Roman; Škorík, Viktor; Kruml, Tomáš; Man, Jiří; Lang, K. H.; Polák, Jaroslav

2015-01-01

Roč. 80, NOV (2015), s. 426-433 ISSN 0142-1123 R&D Projects: GA MŠk(CZ) EE2.3.30.0063 Institutional support: RVO:68081723 Keywords : Nickel base superalloy * Thermomechanical fatigue * Dwell time * Lifetime behavior * Damage mechanisms Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.162, year: 2015

Electric Conductivity of Phosphorus Nanowires

International Nuclear Information System (INIS)

Jing-Xiang, Zhang; Hui, Li; Xue-Qing, Zhang; Kim-Meow, Liew

2009-01-01

We present the structures and electrical transport properties of nanowires made from different strands of phosphorus chains encapsulated in carbon nanotubes. Optimized by density function theory, our results indicate that the conductance spectra reveal an oscillation dependence on the size of wires. It can be seen from the density of states and current-voltage curves that the structure of nanowires affects their properties greatly. Among them, the DNA-like double-helical phosphorus nanowire exhibits the distinct characteristic of an approximately linear I – V relationship and has a higher conductance than others. The transport properties of phosphorus nanowires are highly correlated with their microstructures. (condensed matter: structure, mechanical and thermal properties)

On Post-Weld Heat Treatment of a Single Crystal Nickel-Based Superalloy Joint by Linear Friction Welding

Directory of Open Access Journals (Sweden)

T. J. Ma

2015-09-01

Full Text Available Three types of post-weld heat treatment (PWHT, i.e. solution treatment + primary aging + secondary aging (I, secondary aging (II, and primary aging + secondary aging (III, were applied to a single crystal nickel-based superalloy joint made with linear friction welding (LFW. The results show that the grains in the thermomechanically affected zone (TMAZ coarsen seriously and the primary γ' phase in the TMAZ precipitates unevenly after PWHT I. The primary γ' phase in the TMAZ and weld zone (WZ precipitates insufficiently and fine granular secondary γ' phase is observed in the matrix after PWHT II. After PWHT III, the primary γ' phase precipitates more sufficiently and evenly compared to PWHTs I and II. Moreover, the grains in the TMAZ have not coarsened seriously and fine granular secondary γ' phase is not found after PWHT III. PWHT III seems more suitable to the LFWed single crystal nickel-based superalloy joints when performing PWHT.

Strategy for Strengthening Farmer Groups by Institutional Strengthening

Directory of Open Access Journals (Sweden)

Purbayu Budi Santoso

2015-08-01

Full Text Available Agriculture sector becomes a spotlight because this sector will be full of potential but the welfare of farmers who become the leading actor is not guaranteed and has a poor tendency. The purpose of this study is to formulate strategies to strengthen farmers' groups in order to create the marketing of the agricultural sector that benefit farmers. The method used to achieve this goal is to use a qualitative approach and Analytical Network Process. In addition to the secondary data obtained from several agencies, this study also uses primary data obtained by in-depth interviews and observations. This research results a priority of aspects of the institutional strengthening of farmer groups as well as priority issues and priorities of the solution of each aspect. In addition, the priority of alternative strategies resulted based on the problems and solutions that have been analyzed in order to solve the problems in the institutional strengthening of farmer groups in Demak.

Production of carrier-free phosphorus-33 at MURR

International Nuclear Information System (INIS)

Jia, W.; Ketring, A.R.; Schuh, J.; Lanigan, J.; Ma, D.; Manson, L.; Chanley, D.

1996-01-01

Phosphorus-33, a new radionuclide used in medical and biochemical research, is produced at the University of Missouri research reactor (MURR) in production quantities. Phosphorus-33 has a longer shelf life and lower dose rates than phosphorus-32. Recently, the MURR and New England Nuclear (NEN) jointly developed a method to recover carrier-free phosphorus-33 as well as the enriched sulfur target using a sublimation technique at reduced pressure

Prevalence of phosphorus containing food additives in grocery stores

Directory of Open Access Journals (Sweden)

Janeen B. Leon

2012-06-01

In conclusion, phosphorus additives are commonly present in groceries and contribute significantly to the phosphorus content of foods. Moreover, phosphorus additive foods are less costly than additive-free foods. As a result, phosphorus additives may be an important contributor to hyperphosphatemia among persons with chronic kidney disease

The Adequacy of Phosphorus Binder Prescriptions Among American Hemodialysis Patients

Science.gov (United States)

Huml, Anne M.; Sullivan, Catherine M.; Leon, Janeen B.; Sehgal, Ashwini R.

2013-01-01

Because hemodialysis treatment has a limited ability to remove phosphorus, dialysis patients must restrict dietary phosphorus intake and use phosphorus binding medication. Among patients with restricted dietary phosphorus intake (1000 mg/d), phosphorus binders must bind about 250 mg of excess phosphorus per day and among patients with more typical phosphorus intake (1500 mg/d), binders must bind about 750 mg per day. To determine the phosphorus binding capacity of binder prescriptions among American hemodialysis patients, we undertook a cross-sectional study of a random sample of in-center chronic hemodialysis patients. We obtained data for one randomly selected patient from 244 facilities nationwide. About one-third of patients had hyperphosphatemia (serum phosphorus level > 5.5 mg/dL). Among the 224 patients prescribed binders, the mean phosphorus binding capacity was 256 mg/d (SD 143). 59% of prescriptions had insufficient binding capacity for restricted dietary phosphorus intake, and 100% had insufficient binding capacity for typical dietary phosphorus intake. Patients using two binders had a higher binding capacity than patients using one binder (451 vs. 236 mg/d, p phosphorus balance. Use of two binders results in higher binder capacity. Further work is needed to understand the impact of binder prescriptions on mineral balance and metabolism and to determine the value of substantially increasing binder prescriptions. PMID:23013171

Preliminary analysis of phosphorus flow in Hue Citadel.

Science.gov (United States)

Anh, T N Q; Harada, H; Fujii, S; Anh, P N; Lieu, P K; Tanaka, S

2016-01-01

Characteristics of waste and wastewater management can affect material flows. Our research investigates the management of waste and wastewater in urban areas of developing countries and its effects on phosphorus flow based on a case study in Hue Citadel, Hue, Vietnam. One hundred households were interviewed to gain insight into domestic waste and wastewater management together with secondary data collection. Next, a phosphorus flow model was developed to quantify the phosphorus input and output in the area. The results showed that almost all wastewater generated in Hue Citadel was eventually discharged into water bodies and to the ground/groundwater. This led to most of the phosphorus output flowing into water bodies (41.2 kg P/(ha year)) and ground/groundwater (25.3 kg P/(ha year)). Sewage from the sewer system was the largest source of phosphorus loading into water bodies, while effluent from on-site sanitation systems was responsible for a major portion of phosphorus into the ground/groundwater. This elevated phosphorus loading is a serious issue in considering surface water and groundwater protection.

Isotopic techniques to study phosphorus cycling in soils

International Nuclear Information System (INIS)

Manjaiah, K.M.; Sreenivasa Chari, M.; Sachdev, P.; Sachdev, M.S.

2008-01-01

A sound understanding of phosphorus cycling in soil system is essential in order to manage this system in a sustainable manner. Phosphorus transformations are characterized by physico-chemical (sorption-desorption) and biological processes . The transformation rates need to be taken into account while developing nutrient management strategies for economical and sustainable production. One of the important tools and the method gaining popularity for determining the gross transformation rates of nutrients in the soil is the isotopic dilution technique. The major processes in the soil-plant system which determine the distribution and bioavailability of phosphorus in various inorganic and organic soil components consist of: (1) the dissolution of soil mineral phosphates, (2) retention of phosphorus by inorganic soil constituents, (3) decomposition of organic phosphorus contained in plant, animal and microbial detritus and (4) Immobilization of phosphorus via the soil microbial biomass and plan uptake

Research on Liquid Forming Process of Nickel Superalloys Thin Sheet Metals

Directory of Open Access Journals (Sweden)

Hyrcza-Michalska M.

2017-12-01

Full Text Available The paper presents the study of drawability of thin sheet metals made of a nickel superalloy Inconel type. The manufacturing process of axisymmetric cup – cone and a closed section profile in the form of a circular tube were designed and analyzed. In both cases, working fluid-oil was used in place of the rigid tools. The process of forming liquid is currently the only alternative method for obtaining complex shapes, coatings, and especially if we do it with high-strength materials. In the case of nickel superalloys the search for efficient methods to manufacture of the shaped shell is one of the most considerable problems in aircraft industry [1-5]. However, the automotive industries have the same problem with so-called advanced high-strength steels (AHSS. Due to this, both industrial problems have been examined and the emphasis have been put on the process of liquid forming (hydroforming. The study includes physical tests and the corresponding numerical simulations performed, using the software Eta/Dynaform 5.9. Numerical analysis of the qualitative and quantitative forecasting enables the formability of materials with complex and unusual characteristics of the mechanical properties and forming technology. It has been found that only the computer aided design based on physical and numerical modeling, makes efficient plastic processing possible using a method of hydroforming. Drawability evaluation based on the determination of the mechanical properties of complex characteristics is an indispensable element of this design in the best practice of industrial manufacturing products made of thin sheet metals.

Subsurface characterization of an oxidation-induced phase transformation and twinning in nickel-based superalloy exposed to oxy-combustion environments

International Nuclear Information System (INIS)

Zhu Jingxi; Holcomb, Gordon R.; Jablonski, Paul D.; Wise, Adam; Li Jia; Laughlin, David E.; Sridhar, Seetharaman

2012-01-01

Highlights: ►Oxidation products of Ni-based superalloy were studied in oxy-fuel combustion conditions. ► An oxidation-induced phase transformation occurred in the subsurface region. ► One of the two product phases was not in the Ni database of Thermo-Calc. ► This unknown phase is an ordered derivative of FCC structure of Ni–Ti(–Ta) system. ► This phase is likely detrimental to the mechanical integrity of the alloy in use. - Abstract: In the integration of oxy-fuel combustion to turbine power generation system, turbine alloys are exposed to high temperature and an atmosphere comprised of steam, CO 2 and O 2 . While surface and internal oxidation of the alloy takes place, the microstructure in the subsurface region also changes due to oxidation. In this study, bare metal coupons of Ni-base superalloys were exposed in oxy-fuel combustion environment for up to 1000 h and the oxidation-related microstructures were examined. Phase transformation occurred in the subsurface region in Ni-based superalloy and led to twinning. The transformation product phases were analyzed through thermodynamic equilibrium calculations and various electron microscopy techniques, including scanning electron microscopy (SEM), orientation imaging microscopy (OIM) and transmission electron microscopy (TEM). The mechanism by which the phase transformation and the formation of the microstructure occurred was also discussed. The possible effects of the product phases on the performance of the alloy in service were discussed.

MeCrAl coatings obtained by arc PVD and pack cementation processes on nickel base superalloys

International Nuclear Information System (INIS)

Swadzba, L.; Maciejny, A.; Formanek, B.; Mendala, B.

1997-01-01

The paper presents the results of researches on obtaining and structure of high temperature resistance coatings on superalloys. The coatings were deposited on nickel and nickel base superalloys in two stages. During the first stage, the NiCr and NiCrHf coatings were obtained by arc-PVD method. Basic technology, bias, arc current, rotation, parameters of deposition of NiCr and MeCrHf coatings were defined. The high efficiency of deposition of both single and two sources was observed. The targets were made by vacuum melting and machining. An influence of targets chemical composition on coating structure and chemical coatings composition was described. The second stage was made by pack cementation HTLA (high temperature low activity) on 1323 K chromoaluminizing process. These arc-PVD and diffusion (pack cementation) connected processes permitted to obtain MeCrAl and MeCrAlHf type of coatings. The morphology, structure and microchemical composition were characterized by scanning electron microscopy, X-ray microanalysis, energy dispersive X-ray spectroscopy and X-ray diffraction methods. (orig.)

Heredity of medium-range order structure from melts to the microstructure of Ni-Cr-W superalloy

Energy Technology Data Exchange (ETDEWEB)

Gao, Zhongtang; Hu, Rui; Wang, Jun; Li, Jinshan [Northwestern Polytechnical University, State Key Laboratory of Solidification Processing, Xi' an (China)

2015-07-15

The structure factor S(Q), intensities and pair distribution function g(r) of liquid Ni-Cr-W superalloy at different temperatures have been measured by a high-temperature X-ray diffractometer. Coordination N{sub min}, correlation radius r{sub c}, the nearest atomic distance r{sub 1}, solidification microstructure and compression performance have been studied. The results show that a pre-peak exists on the structure factor curve at the liquidus temperature, and a fine structure of equiaxed, globular and non-dendritic primary grains can be achieved by casting the alloy at liquidus temperature. Liquid structure feature of Ni-Cr-W superalloy is found to depend on temperature. During the solidification, some structural information carried by the medium-range order (MRO) structure is inherited from the melt to the microstructure, which is beneficial for grain refinement. The maximum yield strength measured from typical microstructure of the equiaxed and non-dendritic grains at 1400 C is 543 MPa. The results show that refinement and non-dendritic grain is beneficial to the improvement of the yield strength. (orig.)

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.

ESR studies of high-energy phosphorus-ion implanted synthetic diamond crystals

Energy Technology Data Exchange (ETDEWEB)

Isoya, J [University of Library and Information Science, Tsukuba, Ibaraki (Japan); Kanda, H; Morita, Y; Ohshima, T

1997-03-01

Phosphorus is among potential n-type dopants in diamond. High pressure synthetic diamond crystals of type IIa implanted with high energy (9-18 MeV) phosphorus ions have been studied by using electron spin resonance (ESR) technique. The intensity and the linewidth of the ESR signal attributed to the dangling bond of the amorphous phase varied with the implantation dose, suggesting the nature of the amorphization varies with the dose. The ESR signals of point defects have been observed in the low dose as-implanted crystals and in the high dose crystals annealed at high temperature and at high pressure. (author)

Performance of fertigation technique for phosphorus application in cotton

Directory of Open Access Journals (Sweden)

M. Aslam

2009-05-01

Full Text Available Low native soil phosphorus availability coupled with poor utilization of added phosphorus is one of the major constraints limiting the productivity of the crops. With a view of addressing this issue, field studies were conducted to compare the relative efficacy of broadcast and fertigation techniques for phosphorus application during 2005-2006 using cotton as a test crop. Two methods of phosphorus application i.e. broadcast and fertigation were evaluated using five levels of P2O5 (0, 30, 45, 60 and 75 kg P2O5 ha -1. Fertigation showed an edge over broadcast method at all levels of phosphorus application. The highest seed cotton yield was recorded with 75 kg P2O5 ha-1. Fertilizer phosphorus applied at the rate of 60 kg ha-1 through fertigation produced 3.4 tons ha-1 of seed cotton yield, which was statistically identical to 3.3 tons recorded with 75 kg ha-1 of broadcast phosphorus. Agronomic performance of phosphorus was influenced considerably by either method of fertilizer application. The seed cotton yield per kg of fertigation phosphorus was 48% higher than the corresponding broadcast application. The results of these studies showed that fertigation was the most efficient method of phosphorus application compared with the conventional broadcast application of fertilizers.

Reaching ultra low phosphorus concentrations by filtration techniques

NARCIS (Netherlands)

Scherrenberg, S.M.

2011-01-01

This research deals with tertiary treatment techniques used for the removal of phosphorus from wastewater treatment plant (WWTP) effluent. The main objective of this research is to obtain ultra low total phosphorus (<0.15 mg total phosphorus/L) concentrations by coagulation, flocculation and

Determination of traces of phosphorus using isotope exchange

International Nuclear Information System (INIS)

Zeman, A.; Kratzer, K.

1976-01-01

A simple and selective radioanalytical method for the determination of phosphorus (0.015 - 5 μg in a 5 ml sample), based on the heterogeneous isotope exchange, has been developed. The sample containing phosphorus is shaken in the presence of molybdate with a standard solution of tetraphenylarsonium molybdophosphate labelled with phosphorus-32 in 1-2 dicloroethan. From the distribution of the activity between the aqueous and organic phases the amount of phosphorus in the sample can be determined. (Authors)

Patient education for phosphorus management in chronic kidney disease

Directory of Open Access Journals (Sweden)

Kalantar-Zadeh K

2013-05-01

Full Text Available Kamyar Kalantar-ZadehHarold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California Irvine’s School of Medicine, Irvine, CA, USAObjectives: This review explores the challenges and solutions in educating patients with chronic kidney disease (CKD to lower serum phosphorus while avoiding protein insufficiency and hypercalcemia.Methods: A literature search including terms “hyperphosphatemia,” “patient education,” “food fatigue,” “hypercalcemia,” and “phosphorus–protein ratio” was undertaken using PubMed.Results: Hyperphosphatemia is a strong predictor of mortality in advanced CKD and is remediated via diet, phosphorus binders, and dialysis. Dietary counseling should encourage the consumption of foods with the least amount of inorganic or absorbable phosphorus, low phosphorus-to-protein ratios, and adequate protein content, and discourage excessive calcium intake in high-risk patients. Emerging educational initiatives include food labeling using a “traffic light” scheme, motivational interviewing techniques, and the Phosphate Education Program – whereby patients no longer have to memorize the phosphorus content of each individual food component, but only a “phosphorus unit” value for a limited number of food groups. Phosphorus binders are associated with a clear survival advantage in CKD patients, overcome the limitations associated with dietary phosphorus restriction, and permit a more flexible approach to achieving normalization of phosphorus levels.Conclusion: Patient education on phosphorus and calcium management can improve concordance and adherence and empower patients to collaborate actively for optimal control of mineral metabolism.Keywords: hyperphosphatemia, renal diet, phosphorus binders, educational programs, food fatigue, concordance

The phosphorus and the transition metals chemistry

International Nuclear Information System (INIS)

Mathey, F.

1988-01-01

The 1988 progress report, concerning the Polytechnic School unit (France), which studies the phosphorus and the transition metals chemistry, is presented. The laboratory activities are related to the following topics: the phosporus heterocyclic chemistry, the phosphorus-carbon double bonds chemistry, the new transition metals phosphorus compounds, the phosphonates and their uses. Some practical applications of homogeneous catalysis and new materials synthesis are investigated. The main results obtained are: the discovery of the tetra-phosphafulvalenes, the utilization of a new synthesis method of the phosphorus-carbon double bonds and the stabilization of the α-phosphonyled carbanions by the lithium diisopropylamidourea. The papers, the congress communications and the thesis are also shown [fr

Management of Natural and Added Dietary Phosphorus Burden in Kidney Disease

Science.gov (United States)

Cupisti, Adamasco; Kalantar-Zadeh, Kamyar

2018-01-01

Phosphorus retention occurs from higher dietary phosphorus intake relative to its renal excretion or dialysis removal. In the gastrointestinal tract the naturally existing organic phosphorus is only partially (~60%) absorbable; however, this absorption varies widely and is lower for plant-based phosphorus including phytate (80%). The latter phosphorus often remains unrecognized by patients and health care professionals, even though it is widely used in contemporary diets, in particular low-cost foods. In a non-enhanced mixed diet, the digestible phosphorus is closely correlated with total protein content, making protein-rich foods a main source of natural phosphorus. Phosphorus burden is more appropriately limited in pre-dialysis patients who are on low protein diets (~0.6 g/kg/day), whereas dialysis patients who require higher protein intake (~1.2 g/kg/day) are subject to a higher dietary phosphorus load. An effective and patient-friendly approach to reduce phosphorus intake without depriving patients of adequate proteins is to educate patients to avoid foods with high phosphorus relative to protein such as egg yolk and those with high amounts of phosphorus-based preservatives such as certain soft drinks and enhanced cheese and meat. Protein-rich foods should be prepared by boiling, which reduces phosphorus as well as sodium and potassium content, or by other types of cooking induced demineralization. The dose of phosphorus-binding therapy should be adjusted separately for the amount and absorbability of phosphorus in each meal. Dietician counselling to address the foregoing aspects of dietary phosphorus management is instrumental for achieving reduction of phosphorus load. PMID:23465504

phosphorus retention data and metadata

Science.gov (United States)

phosphorus retention in wetlands data and metadataThis dataset is associated with the following publication:Lane , C., and B. Autrey. Phosphorus retention of forested and emergent marsh depressional wetlands in differing land uses in Florida, USA. Wetlands Ecology and Management. Springer Science and Business Media B.V;Formerly Kluwer Academic Publishers B.V., GERMANY, 24(1): 45-60, (2016).

Electrically-inactive phosphorus re-distribution during low temperature annealing

Science.gov (United States)

Peral, Ana; Youssef, Amanda; Dastgheib-Shirazi, Amir; Akey, Austin; Peters, Ian Marius; Hahn, Giso; Buonassisi, Tonio; del Cañizo, Carlos

2018-04-01

An increased total dose of phosphorus (P dose) in the first 40 nm of a phosphorus diffused emitter has been measured after Low Temperature Annealing (LTA) at 700 °C using the Glow Discharge Optical Emission Spectrometry technique. This evidence has been observed in three versions of the same emitter containing different amounts of initial phosphorus. A stepwise chemical etching of a diffused phosphorus emitter has been carried out to prepare the three types of samples. The total P dose in the first 40 nm increases during annealing by 1.4 × 1015 cm-2 for the sample with the highly doped emitter, by 0.8 × 1015 cm-2 in the middle-doped emitter, and by 0.5 × 1015 cm-2 in the lowest-doped emitter. The presence of surface dislocations in the first few nanometers of the phosphorus emitter might play a role as preferential sites of local phosphorus gettering in phosphorus re-distribution, because the phosphorus gettering to the first 40 nm is lower when this region is etched stepwise. This total increase in phosphorus takes place even though the calculated electrically active phosphorus concentration shows a reduction, and the measured sheet resistance shows an increase after annealing at a low temperature. The reduced electrically active P dose is around 0.6 × 1015 cm-2 for all the emitters. This can be explained with phosphorus-atoms diffusing towards the surface during annealing, occupying electrically inactive configurations. An atomic-scale visual local analysis is carried out with needle-shaped samples of tens of nm in diameter containing a region of the highly doped emitter before and after LTA using Atom Probe Tomography, showing phosphorus precipitates of 10 nm and less before annealing and an increased density of larger precipitates after annealing (25 nm and less).

Assessing the long term impact of phosphorus fertilization on phosphorus loadings using AnnAGNPS.

Science.gov (United States)

Yuan, Yongping; Bingner, Ronald L; Locke, Martin A; Stafford, Jim; Theurer, Fred D

2011-06-01

High phosphorus (P) loss from agricultural fields has been an environmental concern because of potential water quality problems in streams and lakes. To better understand the process of P loss and evaluate the effects of different phosphorus fertilization rates on phosphorus losses, the USDA Annualized AGricultural Non-Point Source (AnnAGNPS) pollutant loading model was applied to the Ohio Upper Auglaize watershed, located in the southern portion of the Maumee River Basin. In this study, the AnnAGNPS model was calibrated using USGS monitored data; and then the effects of different phosphorus fertilization rates on phosphorus loadings were assessed. It was found that P loadings increase as fertilization rate increases, and long term higher P application would lead to much higher P loadings to the watershed outlet. The P loadings to the watershed outlet have a dramatic change after some time with higher P application rate. This dramatic change of P loading to the watershed outlet indicates that a "critical point" may exist in the soil at which soil P loss to water changes dramatically. Simulations with different initial soil P contents showed that the higher the initial soil P content is, the less time it takes to reach the "critical point" where P loadings to the watershed outlet increases dramatically. More research needs to be done to understand the processes involved in the transfer of P between the various stable, active and labile states in the soil to ensure that the model simulations are accurate. This finding may be useful in setting up future P application and management guidelines.

High-temperature low-cycle fatigue behaviour of HIP treated and untreated superalloy MAR-M247

Czech Academy of Sciences Publication Activity Database

Šulák, Ivo; Obrtlík, Karel; Čelko, L.

2016-01-01

Roč. 54, č. 6 (2016), s. 471-481 ISSN 0023-432X R&D Projects: GA TA ČR(CZ) TA04011525; GA ČR(CZ) GA15-20991S Institutional support: RVO:68081723 Keywords : hot isostatic pressing * high-temperature low cycle fatigue * fatigue life curves * Ni-based superalloy * dislocation structures * planar bands Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.366, year: 2016

Phosphorus sorption-desorption and effects of temperature, pH and salinity on phosphorus sorption in marsh soils from coastal wetlands with different flooding conditions.

Science.gov (United States)

Bai, Junhong; Ye, Xiaofei; Jia, Jia; Zhang, Guangliang; Zhao, Qingqing; Cui, Baoshan; Liu, Xinhui

2017-12-01

Wetland soils act as a sink or source of phosphorus (P) to the overlaying water due to phosphorus sorption-desorption processes. Litter information is available on sorption and desorption behaviors of phosphorus in coastal wetlands with different flooding conditions. Laboratory experiments were conducted to investigate phosphorus sorption-desorption processes, fractions of adsorbed phosphorus, and the effects of salinity, pH and temperature on phosphorus sorption on soils in tidal-flooding wetlands (TW), freshwater-flooding wetlands (FW) and seasonal-flooding wetlands (SW) in the Yellow River Delta. Our results showed that the freshly adsorbed phosphorus dominantly exists in Occluded-P and Fe/AlP and their percentages increased with increasing phosphorus adsorbed. Phosphorus sorption isotherms could be better described by the modified Langmuir model than by the modified Freundlich model. A binomial equation could be properly used to describe the effects of salinity, pH, and temperature on phosphorus sorption. Phosphorus sorption generally increased with increasing salinity, pH, and temperature at lower ranges, while decreased in excess of some threshold values. The maximum phosphorus sorption capacity (Q max ) was larger for FW soils (256 mg/kg) compared with TW (218 mg/kg) and SW soils (235 mg/kg) (p < 0.05). The percentage of phosphorus desorption (P des ) in the FW soils (7.5-63.5%) was much lower than those in TW (27.7-124.9%) and SW soils (19.2-108.5%). The initial soil organic matter, pH and the exchangeable Al, Fe and Cd contents were important factors influencing P sorption and desorption. The findings of this study indicate that freshwater restoration can contribute to controlling the eutrophication status of water bodies through increasing P sorption. Copyright © 2017 Elsevier Ltd. All rights reserved.

The study of Phosphorus distribution at Putrajaya Wetland

Science.gov (United States)

Mubin Zahari, Nazirul; Malek, Nur Farzana Fasiha Abdul; Fai, Chow Ming; Humaira Haron, Siti; Hafiz Zawawi, Mohd; Nazmi Ismail, Iszmir; Mohamad, Daud; Syamsir, Agusril; Sidek, Lariyah Mohd; Zakwan Ramli, Mohd; Ismail, Norfariza; Zubir Sapian, Ahmad; Noordin, Normaliza; Rahaman, Nurliyana Abdul; Muhamad, Yahzam; Mat Saman, Jarina

2018-04-01

This study is concerning phosphorus distribution in Putrajaya Wetland. Phosphorus is one of the important component in nutrients for living things be it aquatic or non – aquatic organisms. Total phosphorus (TP) results will give some information on the trophic status of surface water in water bodies. The focus of this study is to determine the total phosphorus concentration in Putrajaya Wetland which is in the inlet of the wetland then outlet of the wetland (Central Wetland Lake). The water sample is taken from Putrajaya Wetland and the test was conducted in the laboratory. The result from this study shows the results for total phosphorus according to month, sampling station and cells. Lowest total phosphate at the Central Wetland compare with all the wetland arms cells.

Development of a Ni-based superalloy with cellular structure and interconnected micro porosity

International Nuclear Information System (INIS)

Bernabe, A.; Lopez, E.; Gil-Sevillano, J.

1998-01-01

A cellular metallic material with interconnected porosity of controlled size of an order of 10 μm has been developed by electrochemical dissolution of tungsten grains in a W-Ni-Fe heavy alloy. The nickel superalloy with sponge structure and high surface/volume ratio can also be processed recycling chips from heavy metal machining (Patent number p9700191, 1997). Applications for the new materials could be found as support for catalysts, high temperature filters for corrosive fluids, burners, etc. (Author) 10 refs

Formation and Dissolution of gamma ' Precipitates in IN792 Superalloy at Elevated Temperatures

Czech Academy of Sciences Publication Activity Database

Strunz, Pavel; Petrenec, Martin; Polák, Jaroslav; Gasser, U.; Farkas, G.

2016-01-01

Roč. 6, č. 2 (2016), č. článku 37. ISSN 2075-4701 R&D Projects: GA ČR GB14-36566G; GA MŠk(CZ) LM2011019 EU Projects: European Commission(XE) 283883 - NMI3-II Institutional support: RVO:61389005 ; RVO:68081723 Keywords : metals * high temperature alloys * superalloy * precipitation * neutron scattering * in-situ neutron diffraction * small-angle neutron scattering Subject RIV: BM - Solid Matter Physics ; Magnetism; JL - Materials Fatigue, Friction Mechanics (UFM-A) Impact factor: 1.984, year: 2016

Electrical activation of phosphorus in silicon

International Nuclear Information System (INIS)

Goh, K.E.J.; Oberbeck, L.; Simmons, M.Y.; Clark, R.G.

2003-01-01

Full text: We present studies of phosphorus δ-doping in silicon with a view to determining the degree of electrical activation of the dopants. These results have a direct consequence for the use of phosphorus as a qubit in a silicon-based quantum computer such as that proposed by Kane. Room temperature and 4 K Hall effect measurements are presented for phosphorus δ-doped layers grown in n-type silicon using two different methods. In the first method, the δ-layer was deposited by a phosphorus effusion cell in an MBE chamber. In the second method, the Si surface was dosed with phosphine gas and then annealed to 550 deg C to incorporate P into the substrate. In both methods, the P δ-doped layer was subsequently encapsulated by ∼25 nm of Si grown epitaxially. We discuss the implications of our results on the fabrication of the Kane quantum computer

L12-phase cutting during high temperature and low stress creep of a Re-containing Ni-base single crystal superalloy

Czech Academy of Sciences Publication Activity Database

Kostka, A.; Maelzer, G. (ed.); Eggeler, G.; Dlouhý, Antonín; Reese, S.; Mack, T.

2007-01-01

Roč. 42, č. 11 (2007), s. 3951-3957 ISSN 0022-2461 Institutional research plan: CEZ:AV0Z20410507 Keywords : nickel-base superalloys * single crystals * creep Subject RIV: JG - Metallurgy Impact factor: 1.081, year: 2007

Recovery of phosphorus from sewerage treatment sludge

Energy Technology Data Exchange (ETDEWEB)

Manuilova, Anastasia

1999-07-01

This thesis is a review of the current state of technologies for the removal of phosphorus from wastewater and sludge, and the recovery and re-use of phosphorus. It explains the need for phosphorus removal and describes the current removal processes. Focus is given to phosphorus crystallisation processes and to the processes which treat sewage treatment sludges into potential sources of phosphorus. An interesting possibility to recover phosphorus from sewage sludge by use of Psenner fractionation is also discussed. By this method, the following phosphate fractions of technological significance may be distinguished: (1) redox sensitive phosphates, mainly bound to Fe(OH){sub 3}; (2) phosphate adsorbed to surfaces (Al{sub 2}O{sub 3}), exchangeable against OH{sup -}, and alkali-soluble phosphate; (3) phosphate bound to CaCO{sub 3}, MgCO{sub 3} and in apatite; and (4) organically bound phosphate. The basic removal mechanisms, process schemes and treatment results are described. Two experiments with three different types of sludges from Henriksdal wastewater treatment plant in Stockholm were performed in the laboratory. It was shown that the addition of sodium hydroxide or hydrochloric acid cause the significant release of phosphate (about 80%) for all types of sludges. If a whole Psenner fractionation was performed the phosphate release is approximately 100%.

Synthesis and investigation of the structure and chemical properties of acyclic compounds of bicoordinated phosphorus with a phosphorus-carbon (p-p)/sub π/ bond

International Nuclear Information System (INIS)

Markovskii, L.N.; Romanenko, V.D.

1987-01-01

Five types of reactions of phosphoalkenes can be distinguished according to the nature of the change in the coordination number and valence of the phosphorus atom in the course of chemical conversions. There are: reactions of cyclodimerization, cycloaddition, and 1,2-addition at the P-C double bond; formation of compounds of tricoordinated pentavalent phosphorus; formation of tetracoordinated phosphorus compounds; reactions of functionalization occurring without a change in the valence and coordination number of the phosphorus atom; and reactions of 1,2-elimination, leading to compounds of monocoordinated phosphorus. This paper reviews each of these reactions in detail, using double-resonance hydrogen 1 and phosphorus 31 NMR spectra and analyzing the acquired chemical shift and spin-spin coupling constants, and also demonstrates the complexation of phosphorus with several metals

The challenge of controlling phosphorus in chronic kidney disease.

Science.gov (United States)

Cannata-Andía, Jorge B; Martin, Kevin J

2016-04-01

The pathogenesis and management of chronic kidney disease-mineral bone disorders (CKD-MBD) has experienced major changes, but the control of serum phosphorus at all stages of CKD still seems to be a key factor to improve clinical outcomes. High serum phosphorus is the most important uremia-related, non-traditional risk factor associated with vascular calcification in CKD patients and in the general population. Phosphorus may also be one of the key elements linking vascular calcification with low bone turnover. The main hormones and factors that contribute to the kidney regulation of phosphorus and calcium include parathyroid hormone, FGF-23, klotho and 1,25-dihydroxyvitamin D (1,25(OH)2D). Serum phosphorus did not start rising until CKD 3b in contrast with the earlier changes observed with fibroblast growth factor-23 (FGF-23), Klotho, calcitriol and parathyroid hormone (PTH). Despite FGF-23 and PTH having synergic effects regarding phosphorus removal, they have opposite effects on 1,25(OH)2D3. At the same stages of CKD in which phosphorus retention appears to occur, calcium retention also occurs. As phosphorus accumulation is associated with poor outcomes, an important question without a clear answer is at which level-range should serum phosphorus be maintained at different stages of CKD to improve clinical outcomes. There are four main strategies to manage phosphate homeostasis; phosphorus dietary intake, administration of phosphate binder agents, effective control of hyperparathyroidism and to ensure in the CKD 5D setting, an adequate scheme of dialysis. Despite all the available strategies, and the introduction of new phosphate binder agents in the market, controlling serum phosphorus remains challenging, and hyperphosphatemia continues to be extremely common in CKD 5 patients. Furthermore, despite phosphate binding agents having proved to be effective in reducing serum phosphorus, their ultimate effects on clinical outcomes remain controversial. Thus, we still

Availability for plants of phosphorus in some virgin peat samples

Directory of Open Access Journals (Sweden)

Armi Kaila

1958-01-01

Full Text Available The availability to plants of native peat phosphorus was studied by chemical methods and by a pot experiment in which three successive oat crops were grown with peat as the only source of phosphorus. The eight samples were collected from virgin peat lands. They were air-dried and ground. The samples were found to represent three different types of phosphorus condition: the first group contained relatively high amounts of inorganic phosphorus which was fairly easily available; the second group had a very high capacity to fix phosphorus which made its high quantity of inorganic phosphorus difficultly available; the third group was very poor in total and inorganic phosphorus but the latter was easily soluble and available to plants. On the basis of the capacity and intensity factors determined according to the method by Teräsvuori and also on the basis of inorganic phosphorus extractable by water fairly reliable predictions could be made of the mutual order of the samples as phosphorus supplyer to the plants in the pot experiment. In an incubation experiment at 27°C the amounts of organic phosphorus mineralized during the period of four months were in some of the samples quite marked, even 40 mg/l, and in most of the samples they corresponded to 5 to 15 per cent of the organic phosphorus. The amounts of phosphorus taken up by the oat crops under the favourable conditions of the pot experiment varied from 11 to 60 mg/l or from 20 to 120 kg/ha.

Recovery of phosphorus compounds from thermally-processed wastes

Science.gov (United States)

Czechowska-Kosacka, A.; Pawłowski, L.; Niedbala, G.; Cel, W.

2018-05-01

Depletion of phosphorus deposits is one of the most serious global problems, which may soon lead to a crisis in food production. It is estimated that if the current living standard is maintained, the available reserves will be depleted in 130 years. Considering the principle of sustainable development, searching for alternative phosphorus sources is extremely important. The work presented the results of the research on the possibility of utilizing wastes as a source of phosphorus. The studies were conducted on poultry manure. The physicochemical properties of phosporus-rich wastes were determined as well. The fertilizing properties of ashes from poultry manure combustion – obtained from different systems, i.e. caged and barn production. The assimilability of phosphorus from the obtained ashes was determined. Potential applications of phosphorus-rich ashes were proposed as well.

A novel unified dislocation density-based model for hot deformation behavior of a nickel-based superalloy under dynamic recrystallization conditions

International Nuclear Information System (INIS)

Lin, Y.C.; Wen, Dong-Xu; Chen, Xiao-Min; Chen, Ming-Song

2016-01-01

In this study, a novel unified dislocation density-based model is presented for characterizing hot deformation behaviors in a nickel-based superalloy under dynamic recrystallization (DRX) conditions. In the Kocks-Mecking model, a new softening item is proposed to represent the impacts of DRX behavior on dislocation density evolution. The grain size evolution and DRX kinetics are incorporated into the developed model. Material parameters of the developed model are calibrated by a derivative-free method of MATLAB software. Comparisons between experimental and predicted results confirm that the developed unified dislocation density-based model can nicely reproduce hot deformation behavior, DRX kinetics, and grain size evolution in wide scope of initial grain size, strain rate, and deformation temperature. Moreover, the developed unified dislocation density-based model is well employed to analyze the time-variant forming processes of the studied superalloy. (orig.)

A novel unified dislocation density-based model for hot deformation behavior of a nickel-based superalloy under dynamic recrystallization conditions

Energy Technology Data Exchange (ETDEWEB)

Lin, Y.C. [Central South University, School of Mechanical and Electrical Engineering, Changsha (China); Light Alloy Research Institute of Central South University, Changsha (China); State Key Laboratory of High Performance Complex Manufacturing, Changsha (China); Wen, Dong-Xu; Chen, Xiao-Min [Central South University, School of Mechanical and Electrical Engineering, Changsha (China); Chen, Ming-Song [Central South University, School of Mechanical and Electrical Engineering, Changsha (China); State Key Laboratory of High Performance Complex Manufacturing, Changsha (China)

2016-09-15

In this study, a novel unified dislocation density-based model is presented for characterizing hot deformation behaviors in a nickel-based superalloy under dynamic recrystallization (DRX) conditions. In the Kocks-Mecking model, a new softening item is proposed to represent the impacts of DRX behavior on dislocation density evolution. The grain size evolution and DRX kinetics are incorporated into the developed model. Material parameters of the developed model are calibrated by a derivative-free method of MATLAB software. Comparisons between experimental and predicted results confirm that the developed unified dislocation density-based model can nicely reproduce hot deformation behavior, DRX kinetics, and grain size evolution in wide scope of initial grain size, strain rate, and deformation temperature. Moreover, the developed unified dislocation density-based model is well employed to analyze the time-variant forming processes of the studied superalloy. (orig.)

Superalloys. Volume 2. 1977-February 1978 (citations from the NTIS data base). Report for 1977--Feb 78

International Nuclear Information System (INIS)

Smith, M.F.

1978-03-01

Federally-funded research on cobalt- and nickel-based superalloys is cited. Casting and powder metallurgy of these alloys are covered. Properties such as heat resistance, corrosion resistance, microstructure, fracture, and creep are described. The use of these materials in nuclear reactors, gas turbine parts, and high-temperature equipment is a major part of this compilation

Phosphorus in antique iron music wire.

Science.gov (United States)

Goodway, M

1987-05-22

Harpsichords and other wire-strung musical instruments were made with longer strings about the beginning of the 17th century. This change required stronger music wire. Although these changes coincided with the introduction of the first mass-produced steel (iron alloyed with carbon), carbon was not found in samples of antique iron harpsichord wire. The wire contained an amount of phosphorus sufficient to have impeded its conversion to steel, and may have been drawn from iron rejected for this purpose. The method used to select pig iron for wire drawing ensured the highest possible phosphorus content at a time when its presence in iron was unsuspected. Phosphorus as an alloying element has had the reputation for making steel brittle when worked cold. Nevertheless, in replicating the antique wire, it was found that lowcarbon iron that contained 0.16 percent phosphorus was easily drawn to appropriate gauges and strengths for restringing antique harpsichords.

Interaction between viologen-phosphorus dendrimers and α-synuclein

International Nuclear Information System (INIS)

Milowska, Katarzyna; Grochowina, Justyna; Katir, Nadia; El Kadib, Abdelkrim; Majoral, Jean-Pierre; Bryszewska, Maria; Gabryelak, Teresa

2013-01-01

In this study the interaction between viologen-phosphorus dendrimers and α-synuclein (ASN) was examined. Polycationic viologen-phosphorus dendrimers (two positive charges per viologen unit) are novel compounds with relatively unknown properties. The influence of these viologen dendrimers on ASN was tested using fluorimetric and circular dichroism methods. ASN contains four tyrosine residues; therefore, the influence of dendrimers on protein molecular conformation by measuring the changes in the ASN fluorescence in the presence of dendrimers was evaluated. The interaction of dendrimers with free L-tyrosine was also monitored. Results show that viologen-phosphorus dendrimers interact with ASN; they quenched the fluorescence of ASN as well as free tyrosine by dynamic and static ways. However, the quenching was not accompanied by modifications in the ASN secondary structure. - Highlights: ► Interaction between viologen-phosphorus dendrimers and α-synuclein (ASN) was investigated. ► Viologen-phosphorus dendrimers can quench the fluorescence of tyrosine in ASN. ► Dendrimers caused red-shift in maximum of fluorescence. ► Viologen-phosphorus dendrimers did not change the secondary structure of ASN.

Ocean acidification: One potential driver of phosphorus eutrophication.

Science.gov (United States)

Ge, Changzi; Chai, Yanchao; Wang, Haiqing; Kan, Manman

2017-02-15

Harmful algal blooms which may be limited by phosphorus outbreak increases currently and ocean acidification worsens presently, which implies that ocean acidification might lead to phosphorus eutrophication. To verify the hypothesis, oxic sediments were exposed to seawater with different pH 30days. If pH was 8.1 and 7.7, the total phosphorus (TP) content in sediments was 1.52±0.50 and 1.29±0.40mg/g. The inorganic phosphorus (IP) content in sediments exposed to seawater with pH8.1 and 7.7 was 1.39±0.10 and 1.06±0.20mg/g, respectively. The exchangeable phosphorus (Ex-P) content in sediments was 4.40±0.45 and 2.82±0.15μg/g, if seawater pH was 8.1 and 7.7. Ex-P and IP contents in oxic sediments were reduced by ocean acidification significantly (pocean acidification was one potential facilitator of phosphorus eutrophication in oxic conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Recycling phosphorus by fast pyrolysis of pig manure: concentration and extraction of phosphorus combined with formation of value-added pyrolysis products

NARCIS (Netherlands)

Azuara, M.; Kersten, Sascha R.A.; Kootstra, A.M.J.

2013-01-01

In order to recycle phosphorus from the livestock chain back to the land, fast pyrolysis of concentrated pig manure at different temperatures (400 °C, 500 °C, 600 °C), was undertaken to concentrate the phosphorus in the char fraction for recovery. Results show that 92%–97% of the phosphorus present

The effects of phosphorus limitation on carbon metabolism in diatoms.

Science.gov (United States)

Brembu, Tore; Mühlroth, Alice; Alipanah, Leila; Bones, Atle M

2017-09-05

Phosphorus is an essential element for life, serving as an integral component of nucleic acids, lipids and a diverse range of other metabolites. Concentrations of bioavailable phosphorus are low in many aquatic environments. Microalgae, including diatoms, apply physiological and molecular strategies such as phosphorus scavenging or recycling as well as adjusting cell growth in order to adapt to limiting phosphorus concentrations. Such strategies also involve adjustments of the carbon metabolism. Here, we review the effect of phosphorus limitation on carbon metabolism in diatoms. Two transcriptome studies are analysed in detail, supplemented by other transcriptome, proteome and metabolite data, to gain an overview of different pathways and their responses. Phosphorus, nitrogen and silicon limitation responses are compared, and similarities and differences discussed. We use the current knowledge to propose a suggestive model for the carbon flow in phosphorus-replete and phosphorus-limited diatom cells.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'. © 2017 The Authors.

Microstructure and mechanical properties of metallic high-temperature materials. Research report

International Nuclear Information System (INIS)

Mughrabi, H.; Gottstein, G.; Mecking, H.; Riedel, H.; Toboloski, J.

1999-01-01

This volume contains 38 lectures of research studies performed in the course of the Priority Programme 'Microstructure and Mechanical Properties of Metallic High-Temperature Materials' supported by the Deutsche Forschungsgemeinschaft (DFG) over a period of six years from 1991 to 1997. The four materials selected were: 1. light metal PM-aluminium and titanium base alloys; 2. ferritic chromium and austenitic alloy 800 steels; 3. (monocrystalline) nickel-base superalloys; and 4. nickel- and iron-base oxide-dispersion-strengthened superalloys. All papers have been abstracted separately for the ENERGY database

Phosphorus and nitrogen in the eutrophication of waters

International Nuclear Information System (INIS)

Salonen, S.; Frisk, T.; Kaermeniemi, T.; Niemi, J.; Pitkaenen, H.; Silvo, K.; Vuoristo, H.

1992-01-01

This report is a summary of the contribution of nitrogen and phosphorus in the eutrophication process of inland and coastal waters. Special attention was paid to the mechanisms of these nutrients in regulating biological processes and to the methods available in estimating their effects in the eutrophication of water bodies. The report includes five chapters which are entitled: Introduction, which is a general background to the subject with special attention to the requirements of the Finnish Water Act. Phosphorus and nitrogen as factors regulating biological processes. The topics included are: definition of eutrophication, forms of phosphorus and nitrogen and their sources to inland and coastal waters, effects of these nutrients as growth factors of phytoplankton and macrophytes and consequences of eutrophication. Estimation of the effects of phosphorus and nitrogen. The topics discussed from the point of view of the tasks of the National Board of Waters and the Environment are: estimation of the effects of phosphorus and nitrogen in the planning and supervision of industry, fish farming, peat production, municipalities, agriculture and forestry. A brief state-of-the art of the research carried out in the National Board of Waters and the Environment is given. Methods of estimating the effects of phosphorus and nitrogen loading in waters. The topics are: relationships between phosphorus and nitrogen concentrations in waters, material balances, water quality models, classification of waters and different groups of organisms as indicators of water quality. Conclusions for the estimation of the effects of phosphorus and nitrogen in receiving waters

A continuum approach to combined $\\gamma/\\gamma'$ evolution and dislocation plasticity in Nickel-based superalloys

OpenAIRE

Wu, Ronghai; Zaiser, Michael; Sandfeld, Stefan

2017-01-01

Creep in single crystal Nickel-based superalloys has been a topic of interest since decades, and nowadays simulations are more and more able to complement experiments. In these alloys, the $\\gamma/\\gamma'$ phase microstructure co-evolves with the system of dislocations under load, and understanding the mutual interactions is essential for understanding the resulting creep properties. Predictive modeling thus requires multiphysics frameworks capable of modeling and simulating both the phase an...

Phosphorus solubility in an acid forest soil as influenced by form of applied phosphorus and liming

International Nuclear Information System (INIS)

Fransson, Ann-Mari; Bergkvist, Bo; Tyler, Germund

1999-01-01

Sedimentary phosphorus, superphosphate, and wood-ash, as well as either sedimentary phosphorus. superphosphate or ash combined with lime, were distributed in selected plots in an 80-yr-old Norway spruce forest [Picea abies (L.) Karst]. After 2 yrs, the sedimentary phosphorus had increased the oxalate/oxalic acid-extractable P in the O-horizon, and the superphosphate had increased the oxalate/oxalic acid-extractable P in the E-horizon. At first, the percolation water from the superphosphate treatment showed high P concentrations. It soon returned to control levels, however. The percolation water from the sedimentary phosphorus treatment gradually showed increased phosphate concentrations. The wood-ash increased neither the amount of extractable P nor the P concentration in the percolation water. The oxalate/oxalic acid-extractable P from the sedimentary P treatment was reduced by liming. The P concentration in the percolation water also tended to be reduced. This was perhaps due to formation of Ca phosphates in the vicinity of the lime particles. In addition, if the solubility rate was similar to the uptake rate, it could account for the decreased P concentration

Microstructure and mechanical properties of the superalloy ATI Allvac 718Plus

International Nuclear Information System (INIS)

Zickler, Gerald A.; Schnitzer, Ronald; Radis, Rene; Hochfellner, Rainer; Schweins, Ralf; Stockinger, Martin; Leitner, Harald

2009-01-01

ATI Allvac 718Plus is a novel nickel-based superalloy, which was designed for heavy-duty applications in aerospace turbines. In the present study the high-resolution investigation techniques, atom probe tomography, electron microscopy and in situ high-temperature small-angle neutron scattering were used for a comprehensive microstructural characterization. The alloy contains nanometer-sized spherical γ' phase precipitates (Ni 3 (Al,Ti)) and plate-shaped δ phase precipitates (Ni 3 Nb) of micrometer size. The precipitation kinetics of the γ' phase can be described by a classical model for coarsening. The precipitation strongly influences the mechanical properties and is of high scientific and technological interest.

On γ and γ' phases composition in IN-100 superalloy after high-temperature exposure

International Nuclear Information System (INIS)

Matteazzi, P.; Principi, G.; Ramous, E.

1981-01-01

The chemistry and volume fraction of UPSILON' phase in IN-100 superalloy after high-temperature exposure in furnace and in service have been examined. Increasing the time of exposure aluminium plus titanium content remains nearly constant and very close to 25 at.%; the little decrease of nickel together with the increase of iron and molybdenum suggest that the last two elements are preferentially occupying Ni-type sites, according to the pair potential model of UPSILON'. (orig.)

Effects of white phosphorus on mallard reproduction

Science.gov (United States)

Vann, S.I.; Sparling, D.W.; Ottinger, M.A.

2000-01-01

Extensive waterfowl mortality involving thousands of ducks, geese, and swans has occurred annually at Eagle River Flats, Alaska since at least 1982. The primary agent for this mortality has been identified as white phosphorus. Although acute and subacute lethality have been described, sublethal effects are less well known. This study reports on the effects of white phosphorus on reproductive function in the mallard (Anas platyrhynchos) in captivity. Fertility, hatching success, teratogenicity, and egg laying frequency were examined in 70 adult female mallards who received up to 7 daily doses of 0, 0.5, 1.0, and 2.0 mg/kg of white phosphorus. Measurements of fertility and hatchability were reduced by the white phosphorus. Teratogenic effects were observed in embryos from hens dosed at all treatment levels. Egg laying frequency was reduced even at the lowest treatment level; treated hens required a greater number of days to lay a clutch of 12 eggs than control hens. After two doses at 2.0 mg/kg, all females stopped laying completely for a minimum of 10 days and laying frequency was depressed for at least 45 days. Fertility of 10 adult male mallards dosed with 1.0 mg/kg of white phosphorus did not differ from 10 controls, but plasma testosterone levels were significantly (p free-ranging mallards may be impaired if they are exposed to white phosphorus at typical field levels.

Hot corrosion behavior of Ni based Inconel 617 and Inconel 738 superalloys

Energy Technology Data Exchange (ETDEWEB)

El-Awadi, G.A., E-mail: gaberelawdi@yahoo.com [Atomic Energy Authority, NRC, Cyclotron Project, Abo-zabal, 13759 Cairo (Egypt); Abdel-Samad, S., E-mail: salem_abdelsamad@yahoo.com [Atomic Energy Authority, NRC, Cyclotron Project, Abo-zabal, 13759 Cairo (Egypt); Elshazly, Ezzat S. [Atomic Energy Authority, NRC, Metallurgy Dept., Abo-zabal, 13759 Cairo (Egypt)

2016-08-15

Highlights: • Supperalloy good resistance to high temperature oxidation. • Ni-base alloy IN738 and Inconel 617 good resistance to hot corrosion. • Corrosion resistance of supperalloys depending on environment of abrasive ions such as (NaCl or NaSO{sub 4}). • Hot corrosion resistance depend on what the oxides phases where formed. - Abstract: Superalloys are extensively used at high temperature applications due to their good oxidation and corrosion resistance properties in addition to their high stability were made at high temperature. Experimental measurements of hot corrosion at high temperature of Inconel 617 and Inconel 738 superalloys. The experiments were carried out at temperatures 700 °C, 800 °C and 900 °C for different exposure times to up to 100 h. The corrosive media was NaCl and Na{sub 2}SO{sub 4} sprayed on the specimens. Seven different specimens were used at each temperature. The corrosion process is endothermic and the spontaneity increased by increasing temperature. The activation energy was found to be Ea = 23.54 and E{sub a} = 25.18 KJ/mol for Inconel 738 and Inconel 617 respectively. X-ray diffraction technique (XRD) was used to analyze the formed scale. The morphology of the specimen and scale were examined by scanning electron microscopy (SEM). The results show that the major corrosion products formed were NiCr{sub 2}O{sub 4}, and Co Cr{sub 2}O{sub 4} spinles, in addition to Cr{sub 2}O{sub 3}.

Black phosphorus saturable absorber for ultrashort pulse generation

Energy Technology Data Exchange (ETDEWEB)

Sotor, J., E-mail: jaroslaw.sotor@pwr.edu.pl; Sobon, G.; Abramski, K. M. [Laser and Fiber Electronics Group, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, Wroclaw 50-370 (Poland); Macherzynski, W.; Paletko, P. [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, Wroclaw 50-372 (Poland)

2015-08-03

Low-dimensional materials, due to their unique and versatile properties, are very interesting for numerous applications in electronics and optoelectronics. Recently rediscovered black phosphorus, with a graphite-like layered structure, can be effectively exfoliated up to the single atomic layer called phosphorene. Contrary to graphene, it possesses a direct band gap controllable by the number of stacked atomic layers. For those reasons, black phosphorus is now intensively investigated and can complement or replace graphene in various photonics and electronics applications. Here, we demonstrate that black phosphorus can serve as a broadband saturable absorber and can be used for ultrashort optical pulse generation. The mechanically exfoliated ∼300 nm thick layers of black phosphorus were transferred onto the fiber core, and under pulsed excitation at 1560 nm wavelength, its transmission increases by 4.6%. We have demonstrated that the saturable absorption of black phosphorus is polarization sensitive. The fabricated device was used to mode-lock an Er-doped fiber laser. The generated optical solitons with the 10.2 nm bandwidth and 272 fs duration were centered at 1550 nm. The obtained results unambiguously show that black phosphorus can be effectively used for ultrashort pulse generation with performances similar or even better than currently used graphene or carbon nanotubes. This application of black phosphorus proves its great potential to future practical use in photonics.

Strain-induced γ{sup '}-coarsening during aging of Ni-based superalloys under uniaxial load. Modeling and analysis

Energy Technology Data Exchange (ETDEWEB)

Mushongera, Leslie T.

2016-07-28

Turbine blades which are used in the hot paths of aerospace or industrial gas turbines are usually manufactured as casted single crystalline parts. However, even though grain boundaries are excluded, the degradation behavior of respectively developed single crystal nickel-base superalloys, is still quite complex involving a number of very different microscopic effects. One of these is the diffusion-limited coarsening of the γ{sup '}-precipitates. Long-term aging or creep loading along the <100> crystallographic orientation results in the anisotropic coarsening of the γ{sup '}-precipitates. In the end, the microstructure contains quite large, irregularly shaped precipitates or plate-like precipitates aligned either parallel (P-type rafts) or perpendicular (N-type rafts) to the loading direction. This behavior is detrimental for the properties of these materials since their superior properties emanate from the size, morphology and distribution of the γ{sup '}-precipitates [R. Reed: Cambridge University Press, (2006)]. In order to efficiently design these materials, the phenomenon of coarsening should be known in detail to optimize the materials accurately. On this background, the general objective of this thesis is to develop an integrated computational approach for simulating morphological evolution in single crystal Ni-base superalloys. As a first step towards that aim, a multi-component phase field model coupled to inputs from CALPHAD-type and kinetic databases for the relevant driving forces was developed based on the grand-potential formalism similar to Plapp [Phys. Rev. E, 84: 031601 (2011)]. The thermodynamic formulation of the model was validated by comparisons to ThermoCalc equilibrium calculations and DICTRA sharp-interface simulations. Phase field approaches that allow for anisotropies of the interfacial energy sufficiently high so that the interface develops sharp corners due to missing crystallographic orientations were formulated. This

The nonlinear unloading behavior of a typical Ni-based superalloy during hot deformation. A unified elasto-viscoplastic constitutive model

International Nuclear Information System (INIS)

Chen, Ming-Song; Lin, Y.C.; Li, Kuo-Kuo; Chen, Jian

2016-01-01

In authors' previous work (Chen et al. in Appl Phys A. doi:10.1007/s00339-016-0371-6, 2016), the nonlinear unloading behavior of a typical Ni-based superalloy was investigated by hot compressive experiments with intermediate unloading-reloading cycles. The characters of unloading curves were discussed in detail, and a new elasto-viscoplastic constitutive model was proposed to describe the nonlinear unloading behavior of the studied Ni-based superalloy. Still, the functional relationships between the deformation temperature, strain rate, pre-strain and the parameters of the proposed constitutive model need to be established. In this study, the effects of deformation temperature, strain rate and pre-strain on the parameters of the new constitutive model proposed in authors' previous work (Chen et al. 2016) are analyzed, and a unified elasto-viscoplastic constitutive model is proposed to predict the unloading behavior at arbitrary deformation temperature, strain rate and pre-strain. (orig.)

NASA Lewis Research Center's materials and structures division

International Nuclear Information System (INIS)

Weymueller, C.R.

1976-01-01

Research activities at the NASA Lewis Research Center on materials and structures are discussed. Programs are noted on powder metallurgy superalloys, eutectic alloys, dispersion strengthened alloys and composite materials. Discussions are included on materials applications, coatings, fracture mechanics, and fatigue

Mechanical behavior and strengthening mechanisms in ultrafine grain precipitation-strengthened aluminum alloy

International Nuclear Information System (INIS)

Ma, Kaka; Wen, Haiming; Hu, Tao; Topping, Troy D.; Isheim, Dieter; Seidman, David N.; Lavernia, Enrique J.; Schoenung, Julie M.

2014-01-01

To provide insight into the relationships between precipitation phenomena, grain size and mechanical behavior in a complex precipitation-strengthened alloy system, Al 7075 alloy, a commonly used aluminum alloy, was selected as a model system in the present study. Ultrafine-grained (UFG) bulk materials were fabricated through cryomilling, degassing, hot isostatic pressing and extrusion, followed by a subsequent heat treatment. The mechanical behavior and microstructure of the materials were analyzed and compared directly to the coarse-grained (CG) counterpart. Three-dimensional atom-probe tomography was utilized to investigate the intermetallic precipitates and oxide dispersoids formed in the as-extruded UFG material. UFG 7075 exhibits higher strength than the CG 7075 alloy for each equivalent condition. After a T6 temper, the yield strength (YS) and ultimate tensile strength (UTS) of UFG 7075 achieved 734 and 774 MPa, respectively, which are ∼120 MPa higher than those of the CG equivalent. The strength of as-extruded UFG 7075 (YS: 583 MPa, UTS: 631 MPa) is even higher than that of commercial 7075-T6. More importantly, the strengthening mechanisms in each material were established quantitatively for the first time for this complex precipitation-strengthened system, accounting for grain-boundary, dislocation, solid-solution, precipitation and oxide dispersoid strengthening contributions. Grain-boundary strengthening was the predominant mechanism in as-extruded UFG 7075, contributing a strength increment estimated to be 242 MPa, whereas Orowan precipitation strengthening was predominant in the as-extruded CG 7075 (∼102 MPa) and in the T6-tempered materials, and was estimated to contribute 472 and 414 MPa for CG-T6 and UFG-T6, respectively

Interaction between viologen-phosphorus dendrimers and {alpha}-synuclein

Energy Technology Data Exchange (ETDEWEB)

Milowska, Katarzyna, E-mail: milowska@biol.uni.lodz.pl [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz (Poland); Grochowina, Justyna [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz (Poland); Katir, Nadia [Laboratoire de Chimie de Coordination CNRS, 205 route de Narbonne, 31077 Toulouse (France); El Kadib, Abdelkrim [Institute of Nanomaterials and Nanotechnology (INANOTECH)-MAScIR (Moroccan Foundation for Advanced Science, Innovation and Research), ENSET, Avenue de I' Armee Royale, Madinat El Irfane, 10100 Rabat (Morocco); Majoral, Jean-Pierre [Laboratoire de Chimie de Coordination CNRS, 205 route de Narbonne, 31077 Toulouse (France); Bryszewska, Maria; Gabryelak, Teresa [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz (Poland)

2013-02-15

In this study the interaction between viologen-phosphorus dendrimers and {alpha}-synuclein (ASN) was examined. Polycationic viologen-phosphorus dendrimers (two positive charges per viologen unit) are novel compounds with relatively unknown properties. The influence of these viologen dendrimers on ASN was tested using fluorimetric and circular dichroism methods. ASN contains four tyrosine residues; therefore, the influence of dendrimers on protein molecular conformation by measuring the changes in the ASN fluorescence in the presence of dendrimers was evaluated. The interaction of dendrimers with free L-tyrosine was also monitored. Results show that viologen-phosphorus dendrimers interact with ASN; they quenched the fluorescence of ASN as well as free tyrosine by dynamic and static ways. However, the quenching was not accompanied by modifications in the ASN secondary structure. - Highlights: Black-Right-Pointing-Pointer Interaction between viologen-phosphorus dendrimers and {alpha}-synuclein (ASN) was investigated. Black-Right-Pointing-Pointer Viologen-phosphorus dendrimers can quench the fluorescence of tyrosine in ASN. Black-Right-Pointing-Pointer Dendrimers caused red-shift in maximum of fluorescence. Black-Right-Pointing-Pointer Viologen-phosphorus dendrimers did not change the secondary structure of ASN.

Radiochemical analysis of phosphorus in milk samples

International Nuclear Information System (INIS)

Oliveira, R.M. de; Cunha, I.I.L.

1991-01-01

The determination of phosphorus in milk samples by thermal neutron activation analysis employing radiochemical separation is described. The radiochemical separation consists of the simultaneous irradiation of samples and standards, dissolution of the milk samples in a perchloric acid and nitric acid mixture, addition of zinc hold-back carrier, precipitation of phosphorus as ammonium phospho molybdate (A.M.P.) and sample counting in a Geiger-Mueller detector. The analysis sources of error were studied and the established method was applied to phosphorus analyses in commercial milk samples. (author)

Optimising mechanical properties of hot forged nickel superalloy 625 components

Science.gov (United States)

Singo, Nthambe; Coles, John; Rosochowska, Malgorzata; Lalvani, Himanshu; Hernandez, Jose; Ion, William

2018-05-01

Hot forging and subsequent heat treatment were resulting in substandard mechanical properties of nickel superalloy, Alloy 625, components. The low strength was found to be due to inadequate deformation during forging, excessive grain growth and precipitation of carbides during subsequent heat treatment. Experimentation in a drop forging company and heat treatment facility led to the establishment of optimal parameters to minimise grain size and mitigate the adverse effects of carbide precipitation, leading to successful fulfilment of mechanical property specifications. This was achieved by reducing the number of operations, maximising the extent of deformation by changing the slug dimensions and its orientation in the die, and minimising the time of exposure to elevated temperatures in both the forging and subsequent heat treatment processes to avoid grain growth.

A new model of anomalous phosphorus diffusion in silicon

International Nuclear Information System (INIS)

Budil, M.; Poetzl, H.; Stingeder, G.; Grasserbauer, M.

1989-01-01

A model is presented to describe the 'kink and tail' diffusion of phosphorus. The diffusion behaviour of phosphorus is expplained by the motion of phosphorus-interstitial and phosphorus-vacancy pairs in different charge states. The model yields the enhancement of diffusion in the tail region depending on surface concentration. Furthermore it yields the same selfdiffusion coefficient for interstitials as the gold diffusion experiments. A transformation of the diffusion equation was found to reduce the number of simulation equations. (author) 7 refs., 5 figs

Digestible phosphorus levels for barrows from 50 to 80 kg

Directory of Open Access Journals (Sweden)

Viviane Maria Oliveira dos Santos Nieto

2016-05-01

Full Text Available ABSTRACT This study was carried out to evaluate the levels of digestible phosphorus in diets for barrows with a high potential for lean meat deposition from 50 to 80 kg. Eighty barrows, with an initial weight of 47.93±3.43 kg, were distributed in completely randomized blocks, with each group given five levels of digestible phosphorus (1.86, 2.23, 2.61, 2.99, and 3.36 g kg−1. There were eight replicates, and two animals per experimental unit. Phosphorus levels did not significantly influence feed intake, weight gain, or feed conversion ratio. Daily digestible phosphorus intake increased linearly as levels of phosphorus in the diet were increased. Phosphorus levels did not significantly influence muscle depth, loin eye area, backfat thickness, or the percentage and quantity of lean meat in the carcass. A linear increase was observed for feeding cost as the levels of digestible phosphorus in the diet were increased, and the level of 1.86 g kg−1 cost 29.4% less when compared with the level of 2.61 g kg−1. The dry matter, natural matter, the coefficient of the residue, and volatile solids of the waste were not significantly influenced by phosphorus levels. Conversely, it was possible to observe an increasing linear effect for total solids, total phosphorus, and total nitrogen in the waste of animals receiving diets with increased levels of digestible phosphorus. The level of 1.86 g kg−1, which corresponded to a daily intake of 4.77 g−1 of digestible phosphorus, meets the requirements of barrows weighing 50 to 80 kg.

Chromatography of phosphorus oxoacids

International Nuclear Information System (INIS)

Ohashi, S.

1975-01-01

The present state of studies on the chromatographic separation of phosphorus oxoacids is surveyed. In this paper, chromatographic techniques are divided into four groups, i.e. paper and thin-layer chromatography, paper electrophoresis, ion-exchange chromatography, and gel chromatography. The separation mechanisms and characteristics for these chromatographic methods are discussed and some examples for the separation of phosphorus oxoacids are described. As examples of the application of ion-exchange and gel chromatography, studies on the hot atom chemistry of 32 P in solid inorganic phosphates and those on the substitution reactions between diphosphonate (diphosphite) and polyphosphates are reported. (author)

Effect of phosphorus level on nitrogen accumulation and yield in soybean

International Nuclear Information System (INIS)

You Yubo; Wu Dongmei; Gong Zhenping; Ma Chunmei

2012-01-01

In this paper, the 15 N labeling with sand culture was conducted to study effects of phosphorus level on nitrogen accumulation, nodule nitrogen fixation and yield of soybean plants. Results showed that nitrogen accumulation, fixation and yield of soybean plants all presented a single peak curve with improvement of phosphorus nutrition level, with the peak value of phosphorus concentration in nutrient solution of 31 mg/L. When phosphorus concentration of nutrient solution was 11 mg/L, no obvious promotion was found on the ratio of nodule nitrogen fixation when increasing phosphorus concentration again, However, when phosphorus concentration of nutrient solution was 21 mg/L, increasing phosphorus concentration again had no obvious promotion on soybean plant nitrogen accumulation, nodule nitrogen fixation accumulation and yield, indicating that effect of phosphorus nutrition level on nitrogen fixation was lower than that on yield formation level. (authors)

Radiation induced phosphorus segregation in austenitic and ferritic alloys

International Nuclear Information System (INIS)

Brimhall, J.L.; Baer, D.R.; Jones, R.H.

1984-01-01

The radiation induced surface segregation (RIS) of phosphorus in stainless steel attained a maximum at a dose of 0.8 dpa then decreased continually with dose. This decrease in the surface segregation of phosphorus at high dose levels has been attributed to removal of the phosphorus layer by ion sputtering. Phosphorus is not replenished since essentially all of the phosphorus within the irradiation zone has been segregated to the surface. Sputter removal can explain the previously reported absence of phosphorus segregation in ferritic alloys irradiated at high dosessup(1,2) (>1 dpa) since irradiation of ferritic alloys to low doses has shown measurable RIS. This sputtering phenomenon places an inherent limitation to the heavy ion irradiation technique for the study of surface segregation of impurity elements. The magnitude of the segregation in ferritics is still much less than in stainless steel which can be related to the low damage accumulation in these alloys. (orig.)

Examination of chemical elements partitioning between the γ and γ′ phases in CMSX-4 superalloy using EDS microanalysis and electron tomography

Directory of Open Access Journals (Sweden)

Kruk Adam

2014-01-01

Full Text Available In the present study, the partition of chemical elements between γ and γ′ phases in CMSX-4 was investigated using EDS microanalysis and electron tomography (FIB-SEM and STEM-EDS methods. The investigation has been performed for the superalloy after standard heat treatment and the ex-service CMSX-4 turbine blade after operation for 12 700 hours and 200 starts in industrial gas turbine. The results have shown that Co, Cr and Re partition to the γ matrix, Ni and W are present in both γ and γ′ phases, while Al, Ti and Ta strongly partition to the γ′ phase. The results show the abilities of new analytical electron microscopy and electron tomography methods to characterize the microstructure and chemical composition of single crystal superalloys at the nanoscale.

Fatigue strain mapping via digital image correlation for Ni-based superalloys: The role of thermal activation on cube slip

International Nuclear Information System (INIS)

Mello, Alberto W.; Nicolas, Andrea; Sangid, Michael D.

2017-01-01

A deformation mechanism map for a Ni-based superalloy is presented during cyclic loading at low (300 °C), intermediate (550 °C), and high (700 °C) temperatures for low (0.7%) and high (1.0%) applied strain amplitudes. Strain mapping is performed via digital image correlation (DIC) during interrupted fatigue experiments at elevated temperatures at 1, 10, 100 and 1000 cycles, for each specified loading and temperature condition. The DIC measurements are performed in a scanning electron microscope, which allows high-resolution measurements of heterogeneous slip events and a vacuum environment to ensure stability of the speckle pattern for DIC at high temperatures. The cumulative fatigue experiments show that the slip bands are present in the first cycle and intensify with number of cycles; resulting in highly localized strain accumulation. The strain mapping results are combined with microstructure characterization via electron backscatter diffraction. The combination of crystal orientations and high-resolution strain measurements was used to determine the active slip planes. At low temperatures, slip bands follow the {111} octahedral planes. However, as temperature increases, both the {111} octahedral and {100} cubic slip planes accommodate strain. The activation of cubic slip via cross-slip within the ordered intermetallic γ’ phase has been well documented in Ni-based superalloys and is generally accepted as the mechanism responsible for the anomalous yield phenomenon. The results in this paper represent an important quantifiable study of cubic slip system activity at the mesoscale in polycrystalline γ-γ’ Ni-based superalloys, which is a key advancement to calibrate the thermal activation components of polycrystalline deformation models.

Fatigue strain mapping via digital image correlation for Ni-based superalloys: The role of thermal activation on cube slip

Energy Technology Data Exchange (ETDEWEB)

Mello, Alberto W.; Nicolas, Andrea; Sangid, Michael D., E-mail: msangid@purdue.edu

2017-05-17

A deformation mechanism map for a Ni-based superalloy is presented during cyclic loading at low (300 °C), intermediate (550 °C), and high (700 °C) temperatures for low (0.7%) and high (1.0%) applied strain amplitudes. Strain mapping is performed via digital image correlation (DIC) during interrupted fatigue experiments at elevated temperatures at 1, 10, 100 and 1000 cycles, for each specified loading and temperature condition. The DIC measurements are performed in a scanning electron microscope, which allows high-resolution measurements of heterogeneous slip events and a vacuum environment to ensure stability of the speckle pattern for DIC at high temperatures. The cumulative fatigue experiments show that the slip bands are present in the first cycle and intensify with number of cycles; resulting in highly localized strain accumulation. The strain mapping results are combined with microstructure characterization via electron backscatter diffraction. The combination of crystal orientations and high-resolution strain measurements was used to determine the active slip planes. At low temperatures, slip bands follow the {111} octahedral planes. However, as temperature increases, both the {111} octahedral and {100} cubic slip planes accommodate strain. The activation of cubic slip via cross-slip within the ordered intermetallic γ’ phase has been well documented in Ni-based superalloys and is generally accepted as the mechanism responsible for the anomalous yield phenomenon. The results in this paper represent an important quantifiable study of cubic slip system activity at the mesoscale in polycrystalline γ-γ’ Ni-based superalloys, which is a key advancement to calibrate the thermal activation components of polycrystalline deformation models.

Phosphorus conditions at various depths in some mineral soils

Directory of Open Access Journals (Sweden)

Armi Kaila

1963-05-01

Full Text Available The fractionation method of CHANG and JACKSON (2 was used for the analysing of the distribution of inorganic phosphorus in the topsoil and subsoil of twelve virgin and twelve cultivated soils from various parts of the country; two virgin soils and twenty cultivated soils were studied down to the depths of 60 cm or 70 cm, one even to 2 m. In the more intensively podsolized virgin soils the surface layers, particularly the A2-horizon, are very poor in all the forms of inorganic phosphorus while the enrichment layer will contain fairly high amounts of iron and aluminium bound phosphorus. The application of fertilizers and the other cultivation managements tend to accumulate aluminium and iron bound phosphorus in the plough layer. In some soils the minimum content of calcium bound phosphorus occurs in the layer below the plough layer, but an increase with the depth seems to be typical to it in all the non-Litorina soils, while the first two fractions usually decrease with the depth. In the Litorina soils the iron bound phosphorus is dominant in all the layers studied, but the content of reductant soluble phosphorus is low in these soils, and their content of calcium bound phosphorus is higher than the content of phosphorus bound by aluminium. The predominance of calcium phosphate in the subsoil and the rather low content of reductant soluble and occluded fractions indicate that the chemical weathering in most of our soils is not yet at an advanced stage. The test values determined were in accordance with the results of the fractionation and the estimation of ammonium oxalate soluble aluminium and iron.

In Situ Investigation with Neutrons on the Evolution of γ ' Precipitates at High Temperatures in a Single Crystal Ni-Base Superalloy

Czech Academy of Sciences Publication Activity Database

Gilles, R.; Mukherji, D.; Eckerlebe, H.; Strunz, Pavel; Rösler, J.

2011-01-01

Roč. 278, - (2011), s. 42-47 ISSN 1022-6680 R&D Projects: GA ČR(CZ) GAP204/11/1453 Institutional research plan: CEZ:AV0Z10480505 Keywords : neutron scattering * SANS * superalloys Subject RIV: BM - Solid Matter Physics ; Magnetism

Iron oxides, divalent cations, silica, and the early earth phosphorus crisis

DEFF Research Database (Denmark)

Jones, C.; Nomosatryo, S.; Crowe, S.A.

2015-01-01

As a nutrient required for growth, phosphorus regulates the activity of life in the oceans. Iron oxides sorb phosphorus from seawater, and through the Archean and early Proterozoic Eons, massive quantities of iron oxides precipitated from the oceans, producing a record of seawater chemistry...... that is preserved as banded iron formations (BIFs) today. Here we show that Ca2+, Mg2+, and silica in seawater control phosphorus sorption onto iron oxides, influencing the record of seawater phosphorus preserved in BIFs. Using a model for seawater cation chemistry through time, combined with the phosphorus...... waters shifted from phosphorus to iron limiting....

Preloading Effect on Strengthening Efficiency of RC Beams Strengthened with Non- and Pretensioned NSM Strips

Directory of Open Access Journals (Sweden)

Renata Kotynia

2018-02-01

Full Text Available The near surface mounted (NSM technique has been shown to be one of the most promising methods for upgrading reinforced concrete (RC structures. Many tests carried out on RC members strengthened in flexure with NSM fiber-reinforced polymer (FRP systems have demonstrated greater strengthening efficiency than the use of externally-bonded (EB FRP laminates. Strengthening with simultaneous pretensioning of the FRP results in improvements in the serviceability limit state (SLS conditions, including the increased cracking moment and decreased deflections. The objective of the reported experimental program, which consisted of two series of RC beams strengthened in flexure with NSM CFRP strips, was to investigate the influence of a number of parameters on the strengthening efficiency. The test program focused on an analysis of the effects of preloading on the strengthening efficiency which has been investigated very rarely despite being one of the most important parameters to be taken into account in strengthening design. Two preloading levels were considered: the beam self-weight only, which corresponded to stresses on the internal longitudinal reinforcement of 25% and 14% of the yield stress (depending on a steel reinforcement ratio, and the self-weight with the additional superimposed load, corresponding to 60% of the yield strength of the unstrengthened beam and a deflection equal to the allowable deflection at the SLS. The influence of the longitudinal steel reinforcement ratio was also considered in this study. To reflect the variability seen in existing structures, test specimens were varied by using different steel bar diameters. Finally, the impact of the composite reinforcement ratio and the number of pretensioned FRP strips was considered. Specimens were divided into two series based on their strengthening configuration: series “A” were strengthened with one pretensioned and two non-pretensioned carbon FRP (CFRP strips, while series �

Evaluation of added phosphorus in six volcanic ash soils

International Nuclear Information System (INIS)

Pino N, I.; Casas G, L.; Urbinsa P, M.C.

1984-01-01

The behaviour of added phosphorus in six volcanic ash soils (Andepts) was studied. Two phosphate retention solution were used; one of them labeled with 32 P carrier free. The phosphate retention solution (25 ml) was added to 5 gr of air dry soil. The remainder phosphorus in solution was measured through colorimetry and liquid scintillation. Over 85% phosphorus retention was measured in five soils. A phosphate retention solution labeled with 32 P carrier free proved to be efficient for the determination of phosphorus retention rates in the volcanic ash soils studied. (Author)

Total phosphorus recovery in flowback fluids after gelled hydrocarbon fracturing fluid treatments

Energy Technology Data Exchange (ETDEWEB)

Fyten, G.; Houle, P.; Taylor, R.S. [Halliburton Energy Services, Calgary, AB (Canada); Stemler, P.S. [Petro-Canada Oil and Gas Inc., Calgary, AB (Canada); Lemieux, A. [Omnicon Consultants Inc., Calgary, AB (Canada)

2006-07-01

Carbon dioxide miscible hydrocarbon fracturing fluids are used in unconventional gas reservoirs such as tight gas, shale gas, and coalbed methane. These fracturing fluids address phase trapping concerns by using oil-based fracturing fluid technology for use in reservoirs that are water sensitive. This paper addressed the problem of refinery tower fouling caused by volatile phosphorous components found in phosphate ester oil gellants. In order to address costly unplanned refinery shutdowns, a maximum 0.5 ppm volatile phosphorus in crude specification has been proposed. However, this specification is based on average concentrations of phosphorus added to the oil to gel it. The specification also falsely assumes that the oil is phosphorus free to begin with. The authors noted that refinery tower fouling is actually the result of total phosphorus throughput rather than peak concentrations at any one point. This paper focused on the total phosphorus recovery in addition to peak concentrations. It also examined what percentage of the total recovered phosphorus is in fact volatile, since this is the material that plugs the trays. The total per cent recovery of phosphorus originally added as phosphorus based gellant was examined along with the total percent recovery of volatile phosphorus as a function of total phosphorus. The phosphorus concentrations in both new and reused fracturing fluids before addition of gellants was also examined along with the potential explanations for phosphorus concentrations higher than those originally added. It was shown that the first 50 per cent of a hydraulic fracturing fluid flowback can result in recovery of greater than or less than the amount of phosphorus added to that portion of the fracturing fluid. The initial high concentrations of total and volatile phosphorus are greater than the phosphorus concentrations inherent in the system. Therefore, as flowback continues, there would be a rapid decline in the concentration of phosphorus

Isotopically exchangeable phosphorus

International Nuclear Information System (INIS)

Barbaro, N.O.

1984-01-01

A critique revision of isotope dilution is presented. The concepts and use of exchangeable phosphorus, the phosphate adsorption, the kinetics of isotopic exchange and the equilibrium time in soils are discussed. (M.A.C.) [pt

Neutron activation analysis for calibration of phosphorus implantation dose

International Nuclear Information System (INIS)

Paul, Rick L.; Simons, David S.

2001-01-01

A feasibility study was undertaken to determine if radiochemical neutron activation analysis (RNAA) can be used to certify the retained dose of phosphorus implanted in silicon, with the goal of producing a phosphorus SRM. Six pieces of silicon, implanted with a nominal phosphorus dose of 8.5x10 14 atoms·cm -2 were irradiated at a neutron flux of 1.05x10 14 cm -2 ·s -1 . The samples were mixed with carrier, dissolved in acid, the phosphorus isolated by chemical separation, and 32 P measured using a beta proportional counter. A mean phosphorus concentration of (8.35±0.20)x10 14 atoms·cm -2 (uncertainty=1 standard deviation) was determined for the six samples, in agreement with the nominal implanted dose

Studies on phosphorus utilization as influenced by bacterial seed inoculation and phosphorus fertilization in summer mung (Vigna radiata L. Wilczek)

International Nuclear Information System (INIS)

Kothari, S.K.; Saraf, C.S.

1988-01-01

A greenhouse experiment was conducted with four types of bacterial inoculation (Rhizobium alone; Rhizobium along with Azotobacter chroococcum; Rhizobium along with Azospirillum brasilense and no inoculation) and three levels of phosphorus ( 32 P labelled SSP) application (O, 6.5 ppm and 13.0 ppm P). Inoculation with Rhizobium along with Azotobacter chroococcum was found to be better than Rhizobium alone or Rhizobium along with Azospirillum brasilense in respect of leaf, stem, root and nodule dry weight, phosphorus uptake and utilization efficiency. P application upto 6.5 ppm significantly increased leaf, stem, root and nodule dry weight and phosphorus uptake. Per cent phosphorus derived from fertilizer (per cent pdff) and fertilizer P uptake significantly increased while P utilization efficiency significantly decreased with increasing levels of P application. (author). 12 refs., 2 tables

LCF- and LCF/HCF-behaviour of the superalloy MAR-M247LC

Energy Technology Data Exchange (ETDEWEB)

Gelmedin, Domnin; Lang, Karl-Heinz [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. fuer Werkstoffkunde I

2010-07-01

The fatigue behaviour of the Nickel-base superalloy Mar-M247LC was investigated at 650 C in air environment under total strain control. Pure low cycle fatigue (LCF) loading, pure high cycle fatigue (HCF) loading and superimposed LCF/HCF loading were realised. In LCF tests with a strain ratio of zero and a hold time of 60 seconds the cyclic deformation and the lifetime behaviour was investigated. The dependence of the fatigue limit on the mean strain was estimated in HCF tests at a frequency of 60 Hz using an ultimate number of cycles of ten million. Finally the influence of superimposed HCF and LCF loadings was examined. At high total strain ranges of the HCF loading the lifetime of the superalloy as reduced about more than one magnitude compared to the lifetime under pure LCF loading. With decreasing HCF loadings the reduction of the lifetime decreases. This life time reduction can be explained by the interaction of the LCF and the superimposed HCF loading. Crack initiation and first crack propagation is predominantly induced by the LCF loading. After reaching an adequate long fatigue crack length the superimposed HCF loading contributes considerably to the crack growth. This contribution can be determined evaluating the distance between the LCF marking lines which form on the fracture surface. The higher the superimposed HCF loading was the longer the distance between the LCF marking lines and the lower the crack length were when first LCF marking lines could be recognized. On the basis of this cognition the life time under superimposed LCF/HCF loading was modelled using a model basing on fracture mechanics. (orig.)

Improving phosphorus availability in an acid soil using organic amendments produced from agroindustrial wastes.

Science.gov (United States)

Ch'ng, Huck Ywih; Ahmed, Osumanu Haruna; Majid, Nik Muhamad Ab

2014-01-01

In acid soils, soluble inorganic phosphorus is fixed by aluminium and iron. To overcome this problem, acid soils are limed to fix aluminium and iron but this practice is not economical. The practice is also not environmentally friendly. This study was conducted to improve phosphorus availability using organic amendments (biochar and compost produced from chicken litter and pineapple leaves, resp.) to fix aluminium and iron instead of phosphorus. Amending soil with biochar or compost or a mixture of biochar and compost increased total phosphorus, available phosphorus, inorganic phosphorus fractions (soluble inorganic phosphorus, aluminium bound inorganic phosphorus, iron bound inorganic phosphorus, redundant soluble inorganic phosphorus, and calcium bound phosphorus), and organic phosphorus. This was possible because the organic amendments increased soil pH and reduced exchangeable acidity, exchangeable aluminium, and exchangeable iron. The findings suggest that the organic amendments altered soil chemical properties in a way that enhanced the availability of phosphorus in this study. The amendments effectively fixed aluminium and iron instead of phosphorus, thus rendering phosphorus available by keeping the inorganic phosphorus in a bioavailable labile phosphorus pool for a longer period compared with application of Triple Superphosphate without organic amendments.

Improving Phosphorus Availability in an Acid Soil Using Organic Amendments Produced from Agroindustrial Wastes

Directory of Open Access Journals (Sweden)

Huck Ywih Ch’ng

2014-01-01

Full Text Available In acid soils, soluble inorganic phosphorus is fixed by aluminium and iron. To overcome this problem, acid soils are limed to fix aluminium and iron but this practice is not economical. The practice is also not environmentally friendly. This study was conducted to improve phosphorus availability using organic amendments (biochar and compost produced from chicken litter and pineapple leaves, resp. to fix aluminium and iron instead of phosphorus. Amending soil with biochar or compost or a mixture of biochar and compost increased total phosphorus, available phosphorus, inorganic phosphorus fractions (soluble inorganic phosphorus, aluminium bound inorganic phosphorus, iron bound inorganic phosphorus, redundant soluble inorganic phosphorus, and calcium bound phosphorus, and organic phosphorus. This was possible because the organic amendments increased soil pH and reduced exchangeable acidity, exchangeable aluminium, and exchangeable iron. The findings suggest that the organic amendments altered soil chemical properties in a way that enhanced the availability of phosphorus in this study. The amendments effectively fixed aluminium and iron instead of phosphorus, thus rendering phosphorus available by keeping the inorganic phosphorus in a bioavailable labile phosphorus pool for a longer period compared with application of Triple Superphosphate without organic amendments.

Occurrence of phosphorus in groundwater and surface water of northwestern Mississippi

Science.gov (United States)

Welch, Heather L.; Kingsbury, James A.; Coupe, Richard H.

2010-01-01

Previous localized studies of groundwater samples from the Mississippi River Valley alluvial (MRVA) aquifer have demonstrated that dissolved phosphorus concentrations in the aquifer are much higher than the national background concentration of 0.03 milligram per liter (mg/L) found in 400 shallow wells across the country. Forty-six wells screened in the MRVA aquifer in northwestern Mississippi were sampled from June to October 2010 to characterize the occurrence of phosphorus in the aquifer, as well as the factors that might contribute to high dissolved phosphorus concentrations in groundwater. Dissolved phosphorus concentrations ranged from 0.12 to 1.2 mg/L with a median concentration of 0.62 mg/L. The predominant subunit of the MRVA aquifer in northwestern Mississippi is the Holocene alluvium in which median dissolved phosphorus concentrations were higher than the Pleistocene valley trains deposits subunit. Highest phosphorus concentrations occurred in water from wells located along the Mississippi River. A general association between elevated phosphorus concentrations and dissolved iron concentrations suggests that reducing conditions that mobilize iron in the MRVA aquifer also might facilitate transport of phosphorus. Using baseflow separation to estimate the contribution of baseflow to total streamflow, the estimated contribution to the total phosphorus load associated with baseflow at the Tensas River at Tendal, LA, and at the Bogue Phalia near Leland, MS, was 23 percent and 8 percent, respectively. This analysis indicates that elevated concentrations of dissolved phosphorus in the MRVA aquifer could be a possible source of phosphorus to streams during baseflow conditions. However, the fate of phosphorus in groundwater discharge and irrigation return flow to streams is not well understood.

Inhomogeneous dislocation structure in fatigued INCONEL 713 LC superalloy at room and elevated temperatures

International Nuclear Information System (INIS)

Petrenec, Martin; Obrtlik, Karel; Polak, Jaroslav

2005-01-01

The dislocations arrangement was studied using transmission electron microscopy in specimens of polycrystalline INCONEL 713 LC superalloy cyclically strained up to failure with constant total strain amplitudes at temperatures 300, 773, 973 and 1073 K. Planar dislocation arrangements in the form of bands parallel to the {1 1 1} planes were observed in specimens cycled at all the temperatures. The bands showed up as thin slabs of high dislocation density cutting both the γ channels and γ' precipitates. Ladder-like bands were observed at room temperature

Phase transformation and liquid density redistribution during solidification of Ni-based superalloy Inconel 718

Directory of Open Access Journals (Sweden)

Wang Ling

2012-08-01

Full Text Available The influences of chemical segregation and phase transformation on liquid density variation during solidification of Ni-based supperalloy Inconel 718 were investigated using SEM and EDS. It was found that significant segregation in liquid prompts high Nb phase to precipitate directly from liquid, which results in the redistribution of alloy elements and liquid density in their vicinity. The term “inter-precipitate liquid density” is therefore proposed and this concept should be applied to determine the solidification behavior of superalloy Inconel 718.

Secondary poisoning of kestrels by white phosphorus

Science.gov (United States)

Sparling, D.W.; Federoff, N.E.

1997-01-01

Since 1982, extensive waterfowl mortality due to white phosphorus (P4) has been observed at Eagle River Flats, a tidal marsh near Anchorage, Alaska. Ducks and swans that ingest P4 pellets become lethargic and may display severe convulsions. Intoxicated waterfowl attract raptors and gulls that feed on dead or dying birds. To determine if avian predators can be affected by secondary poisoning, we fed American kestrels (Falco sparverius) 10-day-old domestic chickens that had been dosed with white phosphorus. Eight of 15 kestrels fed intact chicks with a pellet of P4 implanted in their crops died within seven days. Three of 15 kestrels fed chicks that had their upper digestive tracts removed to eliminate any pellets of white phosphorus also died. Hematocrit and hemoglobin in kestrels decreased whereas lactate dehydrogenaseL, glucose, and alanine aminotransferase levels in plasma increased with exposure to contaminated chicks. Histological examination of liver and kidneys showed that the incidence and severity of lesions increased when kestrels were fed contaminated chicks. White phosphorus residues were measurable in 87% of the kestrels dying on study and 20% of the survivors. This study shows that raptors can become intoxicated either by ingesting portions of digestive tracts containing white phosphorus pellets or by consuming tissues of P4 contaminated prey.

The Spatial-temperal Distribution of Phosphorus Species and the Main Factors Influencing on Phosphorus Transportation in Middle Reaches of the Yarlung Zangbo River, China

Science.gov (United States)

Pu, X.; An, R.; Li, R.; Huang, W.; Li, J.

2017-12-01

The objectives of the current study are to investigate the spatial, temperal variation of phisphorus (P) fraction in middle reaches of the Yarlung Zangbo River of China. Samples were collected in April (dry season), August (wet season), and Octber (normal season) along with the middle reaches from Lazi site to Nuxia sitewhich which is about 1000km long. Sequential extraction were applied to determine the forms of phosphorus in suspended particles and to assess the potential bioavailability of particulate P. The results indicated that the distribution of suspended particle size inflenced not only the total phosphorus concentration, but also the proportions of different forms of phosphorus. The exchangeable phosphorus (Ex-P), Fe-bound-P, Ca-bound-P were the most aboundant forms and the highest proportions of total P. The total P concentrations were closely relative to the concentration of suspended particles. According to the characteristics of suspended particles in the Yarlung Zangbo River, the relationship between the suspended particles size and species of phosphorus was established though statistical analysis. The Ex-P increased with the decreasing of suspended particulate size. The content of bioavailable particulate phosphorus varied greatly with the proportions of particulate size. In genral, the higher the proportion of smaller particle size, the higher the content of bioavailable phosphorus. The main factors which affect the phosphorus transportation in Yarlung Zangbo River had also been discussed.

Phytoextraction of excess soil phosphorus

International Nuclear Information System (INIS)

Sharma, Nilesh C.; Starnes, Daniel L.; Sahi, Shivendra V.

2007-01-01

In the search for a suitable plant to be used in P phytoremediation, several species belonging to legume, vegetable and herb crops were grown in P-enriched soils, and screened for P accumulation potentials. A large variation in P concentrations of different plant species was observed. Some vegetable species such as cucumber (Cucumis sativus) and yellow squash (Cucurbita pepo var. melopepo) were identified as potential P accumulators with >1% (dry weight) P in their shoots. These plants also displayed a satisfactory biomass accumulation while growing on a high concentration of soil P. The elevated activities of phosphomonoesterase and phytase were observed when plants were grown in P-enriched soils, this possibly contributing to high P acquisition in these species. Sunflower plants also demonstrated an increased shoot P accumulation. This study shows that the phytoextraction of phosphorus can be effective using appropriate plant species. - Crop plants such as cucumber, squash and sunflower accumulate phosphorus and thus can be used in the phytoextraction of excess phosphorus from soils

Phytoextraction of excess soil phosphorus

Energy Technology Data Exchange (ETDEWEB)

Sharma, Nilesh C. [Department of Biology, Western Kentucky University, 1906 College Heights Boulevard 11080, Bowling Green, KY 42101-1080 (United States); Starnes, Daniel L. [Department of Biology, Western Kentucky University, 1906 College Heights Boulevard 11080, Bowling Green, KY 42101-1080 (United States); Sahi, Shivendra V. [Department of Biology, Western Kentucky University, 1906 College Heights Boulevard 11080, Bowling Green, KY 42101-1080 (United States)]. E-mail: shiv.sahi@wku.edu

2007-03-15

In the search for a suitable plant to be used in P phytoremediation, several species belonging to legume, vegetable and herb crops were grown in P-enriched soils, and screened for P accumulation potentials. A large variation in P concentrations of different plant species was observed. Some vegetable species such as cucumber (Cucumis sativus) and yellow squash (Cucurbita pepo var. melopepo) were identified as potential P accumulators with >1% (dry weight) P in their shoots. These plants also displayed a satisfactory biomass accumulation while growing on a high concentration of soil P. The elevated activities of phosphomonoesterase and phytase were observed when plants were grown in P-enriched soils, this possibly contributing to high P acquisition in these species. Sunflower plants also demonstrated an increased shoot P accumulation. This study shows that the phytoextraction of phosphorus can be effective using appropriate plant species. - Crop plants such as cucumber, squash and sunflower accumulate phosphorus and thus can be used in the phytoextraction of excess phosphorus from soils.

Do invasive mussels restrict offshore phosphorus transport in Lake Huron?

Science.gov (United States)

Cha, Yoonkyung; Stow, Craig A; Nalepa, Thomas F; Reckhow, Kenneth H

2011-09-01

Dreissenid mussels were first documented in the Laurentian Great Lakes in the late 1980s. Zebra mussels (Dreissena polymorpha) spread quickly into shallow, hard-substrate areas; quagga mussels (Dreissena rostriformis bugensis) spread more slowly and are currently colonizing deep, offshore areas. These mussels occur at high densities, filter large water volumes while feeding on suspended materials, and deposit particulate waste on the lake bottom. This filtering activity has been hypothesized to sequester tributary phosphorus in nearshore regions reducing offshore primary productivity. We used a mass balance model to estimate the phosphorus sedimentation rate in Saginaw Bay, a shallow embayment of Lake Huron, before and after the mussel invasion. Our results indicate that the proportion of tributary phosphorus retained in Saginaw Bay increased from approximately 46-70% when dreissenids appeared, reducing phosphorus export to the main body of Lake Huron. The combined effects of increased phosphorus retention and decreased phosphorus loading have caused an approximate 60% decrease in phosphorus export from Saginaw Bay to Lake Huron. Our results support the hypothesis that the ongoing decline of preyfish and secondary producers including diporeia (Diporeia spp.) in Lake Huron is a bottom-up phenomenon associated with decreased phosphorus availability in the offshore to support primary production.

The Prevalence of Phosphorus Containing Food Additives in Top Selling Foods in Grocery Stores

Science.gov (United States)

León, Janeen B.; Sullivan, Catherine M.; Sehgal, Ashwini R.

2013-01-01

Objective To determine the prevalence of phosphorus-containing food additives in best selling processed grocery products and to compare the phosphorus content of a subset of top selling foods with and without phosphorus additives. Design The labels of 2394 best selling branded grocery products in northeast Ohio were reviewed for phosphorus additives. The top 5 best selling products containing phosphorus additives from each food category were matched with similar products without phosphorus additives and analyzed for phosphorus content. Four days of sample meals consisting of foods with and without phosphorus additives were created and daily phosphorus and pricing differentials were computed. Setting Northeast Ohio Main outcome measures Presence of phosphorus-containing food additives, phosphorus content Results 44% of the best selling grocery items contained phosphorus additives. The additives were particularly common in prepared frozen foods (72%), dry food mixes (70%), packaged meat (65%), bread & baked goods (57%), soup (54%), and yogurt (51%) categories. Phosphorus additive containing foods averaged 67 mg phosphorus/100 gm more than matched non-additive containing foods (p=.03). Sample meals comprised mostly of phosphorus additive-containing foods had 736 mg more phosphorus per day compared to meals consisting of only additive-free foods. Phosphorus additive-free meals cost an average of $2.00 more per day. Conclusion Phosphorus additives are common in best selling processed groceries and contribute significantly to their phosphorus content. Moreover, phosphorus additive foods are less costly than phosphorus additive-free foods. As a result, persons with chronic kidney disease may purchase these popular low-cost groceries and unknowingly increase their intake of highly bioavailable phosphorus. PMID:23402914

The prevalence of phosphorus-containing food additives in top-selling foods in grocery stores.

Science.gov (United States)

León, Janeen B; Sullivan, Catherine M; Sehgal, Ashwini R

2013-07-01

The objective of this study was to determine the prevalence of phosphorus-containing food additives in best-selling processed grocery products and to compare the phosphorus content of a subset of top-selling foods with and without phosphorus additives. The labels of 2394 best-selling branded grocery products in northeast Ohio were reviewed for phosphorus additives. The top 5 best-selling products containing phosphorus additives from each food category were matched with similar products without phosphorus additives and analyzed for phosphorus content. Four days of sample meals consisting of foods with and without phosphorus additives were created, and daily phosphorus and pricing differentials were computed. Presence of phosphorus-containing food additives, phosphorus content. Forty-four percent of the best-selling grocery items contained phosphorus additives. The additives were particularly common in prepared frozen foods (72%), dry food mixes (70%), packaged meat (65%), bread and baked goods (57%), soup (54%), and yogurt (51%) categories. Phosphorus additive-containing foods averaged 67 mg phosphorus/100 g more than matched nonadditive-containing foods (P = .03). Sample meals comprised mostly of phosphorus additive-containing foods had 736 mg more phosphorus per day compared with meals consisting of only additive-free foods. Phosphorus additive-free meals cost an average of $2.00 more per day. Phosphorus additives are common in best-selling processed groceries and contribute significantly to their phosphorus content. Moreover, phosphorus additive foods are less costly than phosphorus additive-free foods. As a result, persons with chronic kidney disease may purchase these popular low-cost groceries and unknowingly increase their intake of highly bioavailable phosphorus. Copyright © 2013 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Phosphorus Processing—Potentials for Higher Efficiency

Directory of Open Access Journals (Sweden)

Ludwig Hermann

2018-05-01

Full Text Available In the aftermath of the adoption of the Sustainable Development Goals (SDGs and the Paris Agreement (COP21 by virtually all United Nations, producing more with less is imperative. In this context, phosphorus processing, despite its high efficiency compared to other steps in the value chain, needs to be revisited by science and industry. During processing, phosphorus is lost to phosphogypsum, disposed of in stacks globally piling up to 3–4 billion tons and growing by about 200 million tons per year, or directly discharged to the sea. Eutrophication, acidification, and long-term pollution are the environmental impacts of both practices. Economic and regulatory framework conditions determine whether the industry continues wasting phosphorus, pursues efficiency improvements or stops operations altogether. While reviewing current industrial practice and potentials for increasing processing efficiency with lower impact, the article addresses potentially conflicting goals of low energy and material use as well as Life Cycle Assessment (LCA as a tool for evaluating the relative impacts of improvement strategies. Finally, options by which corporations could pro-actively and credibly demonstrate phosphorus stewardship as well as options by which policy makers could enforce improvement without impairing business locations are discussed.

The role of phosphorus sources in the growth of lowland rice plant

International Nuclear Information System (INIS)

Sisworo, Widjang Herry

1975-01-01

The role of phosphorus sources in the growth of lowland rice plant was studied using P 32 -labelled superphosphate. The experiment was carried out in the glass house. Three high yielding rice varieties used in the experiment were PB 5, IR 22 and Pelita I/1. Results obtained from the experiment showed that, during early growth, seedlings in the nursery did not require any phosphorus from outside. The phosphorus needed was apparently supplied by the seeds themselves. After 10 days seedlings started using phosphorus from outside the plants. Phosphorus in the plants derived from fertilizer reached 5-12% at 16 days old and 25-40% at transplanting time depending on the varieties. Higher response to phosphorus application in the nursery was given by Pelita I/1, the phosphorus in the plants derived from fertilizer was 40% at transplanting time. The phosphorus requirement was mostly supplied by the application of phosphorus fertilizer till 20 days after transplanting but after 40 days soil-phosphorus became the main source for the plants. (author)

Phosphorus in the feeding of pigs : effect of diet on the absorption and retention of phosphorus by growing pigs

NARCIS (Netherlands)

Jongbloed, A.W.

1987-01-01

An extensive review is given of the literature concerning phosphorus feeding of pigs. Subjects dealt with are: 1. physiological background, regulation and effect of diet composition and nutrient supply on phosphorus absorption and retention; 2. estimation of the amount of P present in the

The microstructure of heat-treated nickel-based superalloy 718Plus

International Nuclear Information System (INIS)

Whitmore, Lawrence; Ahmadi, Mohammad Reza; Guetaz, Laure; Leitner, Harald; Povoden-Karadeniz, Erwin; Stockinger, Martin; Kozeschnik, Ernst

2014-01-01

The microstructure of thermally aged nickel-based 718Plus superalloy is investigated using transmission electron microscopy (TEM). Solution annealing at 980 °C for 30 min is followed by either the standard quenching to room temperature or quenching directly to 788 °C, before isothermal aging at 788 °C for four hours. Micro-hardness and yield strength are measured to compare the effects of the two variations. The size and phase fraction of γ′ precipitates are measured using dark-field TEM and related to the hardness and yield strength through a theoretical model based on coherency and antiphase boundary effects. A population of very small sub-precipitates is observed and the larger γ′ precipitates are investigated in detail using high resolution scanning TEM to reveal information about the chemical ordering

Tensile behavior of nickel-base single-crystal superalloy DD6

Energy Technology Data Exchange (ETDEWEB)

Xiong, Xinhong, E-mail: xiongxh@whut.edu.cn [School of Logistics Engineering, Wuhan University of Technology, Wuhan 430063 (China); Quan, Dunmiao; Dai, Pengdan; Wang, Zhiping [School of Logistics Engineering, Wuhan University of Technology, Wuhan 430063 (China); Zhang, Qiaoxin [School of Mechanical and Electronic Engineering, Wuhan University of Technology, Wuhan 430070 (China); Yue, Zhufeng [School of Mechanics Civil Engineering and Architecture, Northwestern Polytechnical University, Xi' an 710072 (China)

2015-06-11

Tensile behavior of the nickel-base single-crystal superalloy DD6 was studied from room temperature to 1020 °C. The plate specimens were along [001] orientation parallel to the loading axis in tension. The microstructures on the surface and fracture morphology were investigated after tensile test to rupture by scanning electron microscopy (SEM). The results of the present investigation indicate that the yield strength at 650 °C is superior to that at room temperature, 850 °C and 1020 °C. Low ductility and serrated flow in stress–strain curves were also observed at 650 °C. The microstructures on the surface of the plate specimens and fracture morphology observation indicated that localized slip which resulted in glide plane decohesion caused the low ductility of DD6 alloy.

Atom probe tomography of Ni-base superalloys Allvac 718Plus and Alloy 718

Energy Technology Data Exchange (ETDEWEB)

Viskari, L., E-mail: viskari@chalmers.se [Chalmers University of Technology, Gothenburg (Sweden); Stiller, K. [Chalmers University of Technology, Gothenburg (Sweden)

2011-05-15

Atom probe tomography (APT) allows near atomic scale compositional- and morphological studies of, e.g. matrix, precipitates and interfaces in a wide range of materials. In this work two Ni-base superalloys with similar compositions, Alloy 718 and its derivative Allvac 718Plus, are subject for investigation with special emphasis on the latter alloy. The structural and chemical nuances of these alloys are important for their properties. Of special interest are grain boundaries as their structure and chemistry are important for the materials' ability to resist rapid environmentally induced crack propagation. APT has proved to be suitable for analyses of these types of alloys using voltage pulsed APT. However, for investigations of specimens containing grain boundaries and other interfaces the risk for early specimen fracture is high. Analyses using laser pulsing impose lower electrical field on the specimen thereby significantly increasing the success rate of investigations. Here, the effect of laser pulsing was studied and the derived appropriate acquisition parameters were then applied for microstructural studies, from which initial results are shown. Furthermore, the influence of the higher evaporation field experienced by the hardening {gamma}' Ni{sub 3}(Al,Nb) precipitates on the obtained results is discussed. -- Research highlights: {yields} Laser pulsed APT is shown to be a good method for analysis of Ni-based superalloys. {yields} The evaporation field is shown to be different for different phases which affects reconstructions. {yields} B and P are shown to segregate to grain boundaries. {yields} Initial results of {delta}-phase analysed by APT are shown.

Remediation of phosphorus from electric furnace waste streams

International Nuclear Information System (INIS)

Hanna, J.; Jung, J.O.

1992-01-01

Electrothermal production of elemental phosphorus (P4) generates substantial amounts of highly toxic phossy water sludge, slag and other gaseous wastes. Because of their high phosphorus content the sludges pose potential fire hazards. In the absence of a reliable processing technology, large amounts of these hazardous wastes are accumulated at an annual rate of 1.5-2.5 million tons from current and past operations. The accumulated sludges are stored in ponds or in special containment vessels in 30 locations in 18 states including Alabama, California, Tennessee, Idaho and Montana. Serious water pollution problems will result unless these wastes are given extensive treatment to remove the elemental phosphorus. Federal regulations prohibit permanent storage of flammable wastes. This paper reports that recently, researchers at the University of Alabama have developed a two-step method for the treatment of phosphorus sludge that includes bulk removal of phosphorus by physical separation techniques followed by remediation of the residual P4 in the sludge using a novel wet air oxidation technique known as HSAD

A Hierarchical Phosphorus Nanobarbed Nanowire Hybrid: Its Structure and Electrochemical Properties.

Science.gov (United States)

Zhao, Dan; Li, Beibei; Zhang, Jinying; Li, Xin; Xiao, Dingbin; Fu, Chengcheng; Zhang, Lihui; Li, Zhihui; Li, Jun; Cao, Daxian; Niu, Chunming

2017-06-14

Nanostructured phosphorus-carbon composites are promising materials for Li-ion and Na-ion battery anodes. A hierarchical phosphorus hybrid, SiC@graphene@P, has been synthesized by the chemical vapor deposition of phosphorus on the surfaces of barbed nanowires, where the barbs are vertically grown graphene nanosheets and the cores are SiC nanowires. A temperature-gradient vaporization-condensation method has been used to remove the unhybridized phosphorus particles formed by homogeneous nucleation. The vertically grown barb shaped graphene nanosheets and a high concentration of edge carbon atoms induced a fibrous red phosphorus (f-RP) growth with its {001} planes in parallel to {002} planes of nanographene sheets and led to a strong interpenetrated interface interaction between phosphorus and the surfaces of graphene nanosheets. This hybridization has been demonstrated to significantly enhance the electrochemical performances of phosphorus.

Overview of phosphorus diffusion and gettering in multicrystalline silicon

International Nuclear Information System (INIS)

Bentzen, A.; Holt, A.

2009-01-01

This paper gives an overview of phosphorus emitter diffusion and gettering as experienced in multicrystalline silicon solar cell processing. The paper gives a brief summary of the diffusion properties of phosphorus in silicon, explaining the nature behind the characteristic kink-and-tail profiles often encountered in silicon solar cells. Then, phosphorus diffusion gettering is discussed with particular focus to the inhomogeneous nature of multicrystalline silicon, and it is discussed how the abundant presence of dislocations in the areas of the material having a low recombination lifetime can cause only minor lifetime enhancements in such areas upon phosphorus diffusion. Attributed to dissociation of precipitated impurities in combination with longer effective diffusion lengths of the impurities, it is then seen that even poor areas of multicrystalline can exhibit a noticeable improvement by phosphorus diffusion gettering when applying a lower diffusion temperature for a longer duration.

The Potential Phosphorus Crisis: Resource Conservation and Possible Escape Technologies: A Review

Directory of Open Access Journals (Sweden)

Saba Daneshgar

2018-06-01

Full Text Available Phosphorus is an essential nutrient for every organism on the Earth, yet it is also a potential environmental pollutant, which may cause eutrophication of water bodies. Wastewater treatment plants worldwide are struggling to eliminate phosphorus from effluents, at great cost, yet current research suggests that the world may deplete the more available phosphorus reserves by around 2300. This, in addition to environmental concerns, evokes the need for new phosphorus recovery techniques to be developed, to meet future generations needs for renewable phosphorus supply. Many studies have been, and are, carried out on phosphorus recovery from wastewater and its sludge, due to their high phosphorus content. Chemical precipitation is the main process for achieving a phosphorus-containing mineral suitable for reuse as a fertilizer, such as struvite. This paper reviews the current status and future trends of phosphorus production and consumption, and summarizes current recovery technologies, discussing their possible integration into wastewater treatment processes, according to a more sustainable water-energy-nutrient nexus.

Predicted impact and evaluation of North Carolina's phosphorus indexing tool.

Science.gov (United States)

Johnson, Amy M; Osmond, Deanna L; Hodges, Steven C

2005-01-01

Increased concern about potential losses of phosphorus (P) from agricultural fields receiving animal waste has resulted in the implementation of new state and federal regulations related to nutrient management. In response to strengthened nutrient management standards that require consideration of P, North Carolina has developed a site-specific P indexing system called the Phosphorus Loss Assessment Tool (PLAT) to predict relative amounts of potential P loss from agricultural fields. The purpose of this study was to apply the PLAT index on farms throughout North Carolina in an attempt to predict the percentage and types of farms that will be forced to change management practices due to implementation of new regulations. Sites from all 100 counties were sampled, with the number of samples taken from each county depending on the proportion of the state's agricultural land that occurs in that county. Results showed that approximately 8% of producers in the state will be required to apply animal waste or inorganic fertilizer on a P rather than nitrogen basis, with the percentage increasing for farmers who apply animal waste (approximately 27%). The PLAT index predicted the greatest amounts of P loss from sites in the Coastal Plain region of North Carolina and from sites receiving poultry waste. Loss of dissolved P through surface runoff tended to be greater than other loss pathways and presents an area of concern as no best management practices (BMPs) currently exist for the reduction of in-field dissolved P. The PLAT index predicted the areas in the state that are known to be disproportionately vulnerable to P loss due to histories of high P applications, high densities of animal units, or soil type and landscapes that are most susceptible to P loss.

Fiber laser welding of nickel based superalloy Inconel 625

Science.gov (United States)

Janicki, Damian M.

2013-01-01

The paper describes the application of single mode high power fiber laser (HPFL) for the welding of nickel based superalloy Inconel 625. Butt joints of Inconel 625 sheets 0,8 mm thick were laser welded without an additional material. The influence of laser welding parameters on weld quality and mechanical properties of test joints was studied. The quality and mechanical properties of the joints were determined by means of tensile and bending tests, and micro hardness tests, and also metallographic examinations. The results showed that a proper selection of laser welding parameters provides non-porous, fully-penetrated welds with the aspect ratio up to 2.0. The minimum heat input required to achieve full penetration butt welded joints with no defect was found to be 6 J/mm. The yield strength and ultimate tensile strength of the joints are essentially equivalent to that for the base material.

Structure of inorganic phosphorus-nitrogen tetrahedral compounds

International Nuclear Information System (INIS)

Vitola, A.; Ronis, J.; Avotins, V.; Millers, T.

1997-01-01

The structure analysis of phosphorus-nitrogen compounds has shown the possibility of the P(O,N) 4 tetrahedra to form various kinds of structures. The wide spectrum of the properties determined by the diversity of structures marks the considerable promise to the future application of phosphorus-nitrogen compounds

Phosphorus dendrimers and photodynamic therapy. Spectroscopic studies on two dendrimer-photosensitizer complexes: Cationic phosphorus dendrimer with rose bengal and anionic phosphorus dendrimer with methylene blue.

Science.gov (United States)

Dabrzalska, Monika; Zablocka, Maria; Mignani, Serge; Majoral, Jean Pierre; Klajnert-Maculewicz, Barbara

2015-08-15

Dendrimers due to their unique architecture may play an important role in drug delivery systems including chemotherapy, gene therapy and recently, photodynamic therapy as well. We investigated two dendrimer-photosensitizer systems in context of potential use of these systems in photodynamic therapy. The mixtures of an anionic phosphorus dendrimer of the second generation and methylene blue were studied by UV-vis spectroscopy while that of a cationic phosphorus dendrimer (third generation) and rose bengal were investigated by spectrofluorimetric methods. Spectroscopic analysis of these two systems revealed the formation of dendrimer-photosensitizer complexes via electrostatic interactions as well as π stacking. The stoichiometry of the rose bengal-cationic dendrimer complex was estimated to be 7:1 and 9:1 for the methylene blue-anionic dendrimer complex. The results suggest that these polyanionic or polycationic phosphorus dendrimers can be promising candidates as carriers in photodynamic therapy. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

Creep, Fatigue and Environmental Interactions and Their Effect on Crack Growth in Superalloys

Science.gov (United States)

Telesman, J.; Gabb, T. P.; Ghosn, L. J.; Smith, T.

2017-01-01

Complex interactions of creep/fatigue/environment control dwell fatigue crack growth (DFCG) in superalloys. Crack tip stress relaxation during dwells significantly changes the crack driving force and influence DFCG. Linear Elastic Fracture Mechanics, Kmax, parameter unsuitable for correlating DFCG behavior due to extensive visco-plastic deformation. Magnitude of remaining crack tip axial stresses controls DFCG resistance due to the brittle-intergranular nature of the crack growth process. Proposed a new empirical parameter, Ksrf, which incorporates visco-plastic evolution of the magnitude of remaining crack tip stresses. Previous work performed at 704C, extend the work to 760C.

Direct observation of thermal disorder and decomposition of black phosphorus

Science.gov (United States)

Yoo, Seung Jo; Kim, Heejin; Lee, Ji-Hyun; Kim, Jin-Gyu

2018-02-01

Theoretical research has been devoted to reveal the properties of black phosphorus as a two-dimensional nanomaterial, but little attention has been paid for the experimental characterization. In this study, the thermal disorder and decomposition of black phosphorus were examined using in situ heating transmission electron microscopy experiments. We observed that the breaking of crystallographic symmetry begins at 380 °C under vacuum condition, followed by the phosphorus evaporates after long-term heating at 400 °C. This decomposition process can be initiated by the surficial vacancy and proceeds toward both interlayer ([010]) and intralayer ([001]) directions. The results on the thermal behavior of black phosphorus provide useful guidance for thin film deposition and fabrication processes with black phosphorus.

Measurement of phosphorus in metals by RNAA

International Nuclear Information System (INIS)

Paul, R.L.

2000-01-01

An RNAA procedure has been developed for measurement of low-level phosphorus in metals. Samples are irradiated at a neutron flux of 2.7 x 10 13 n x cm -2 x s -1 then mixed with carrier and dissolved in acid. After chemical separation and purification of the phosphorus and gravimetric determination of carrier yield, 32 P is determined using a beta proportional counter. The detection limit for a 0.1 g sample irradiated for 30 minutes is 5 μg/kg. The method has been used to determine 6.4 ± 0.6 mg/kg phosphorus is SRM 2175 refractory alloy. (author)

Identification of cowpea cultivars for low phosphorus soils of Nigeria

International Nuclear Information System (INIS)

Afolabi, N.O.; Ogunbodede, B.A.; Adediran, J.A.

1996-01-01

Twenty cultivars of cowpea, Vigna unguiculata, adapted to the Nigerian ecologies were screened to identify cultivars which can give high and sustainable yields when grown on soils with low available phosphorus in a sub-humid climate. Some cultivars including TVX3236, AFB1757, Ogunfowokan and K-28 gave three to four times higher grain yields than the other cultivars at zero phosphorus supply. While phosphorus application reduced grain yield in most of the cultivars with marked reduction in the higher yielding cultivars, low yielding cultivars tended to show some yield increase. Phosphorus use efficiency of the roots, stem or leaves was not significantly correlated with grain yield when 60 KgP/ha was applied. Reduction in yield due to phosphorus application might be due to induced Zn deficiency as Zn supply in these soils has been found to be inherently low. High grain yielding capacity without fertilizer phosphorus application was generally positively correlated with high vegetative shoot dry matter production. However, no clear relationship could be found between grain yield and root dry matter at maturity. It is concluded that selection for phosphorus efficiency in cowpea can substantially contribute to higher cowpea productivity and the farmers income on soils low in available phosphorus in the sub-humid areas of Nigeria. (author). 5 refs, 2 figs, 2 tabs

Identification of cowpea cultivars for low phosphorus soils of Nigeria

Energy Technology Data Exchange (ETDEWEB)

Afolabi, N O; Ogunbodede, B A; Adediran, J A [Obafemi Awolowo Univ., Ibadan (Nigeria). Inst. of Agricultural Research and Training

1996-07-01

Twenty cultivars of cowpea, Vigna unguiculata, adapted to the Nigerian ecologies were screened to identify cultivars which can give high and sustainable yields when grown on soils with low available phosphorus in a sub-humid climate. Some cultivars including TVX3236, AFB1757, Ogunfowokan and K-28 gave three to four times higher grain yields than the other cultivars at zero phosphorus supply. While phosphorus application reduced grain yield in most of the cultivars with marked reduction in the higher yielding cultivars, low yielding cultivars tended to show some yield increase. Phosphorus use efficiency of the roots, stem or leaves was not significantly correlated with grain yield when 60 KgP/ha was applied. Reduction in yield due to phosphorus application might be due to induced Zn deficiency as Zn supply in these soils has been found to be inherently low. High grain yielding capacity without fertilizer phosphorus application was generally positively correlated with high vegetative shoot dry matter production. However, no clear relationship could be found between grain yield and root dry matter at maturity. It is concluded that selection for phosphorus efficiency in cowpea can substantially contribute to higher cowpea productivity and the farmers income on soils low in available phosphorus in the sub-humid areas of Nigeria. (author). 5 refs, 2 figs, 2 tabs.

Effect of carbon additions on the as-cast microstructure and defect formation of a single crystal Ni-based superalloy

International Nuclear Information System (INIS)

Al-Jarba, K.A.; Fuchs, G.E.

2004-01-01

In an effort to reduce grain defects in large single crystal Ni-base superalloy components, carbon is intentionally added. In this study, the effect of carbon additions on the microstructure and solidification defect formation of a model Ni-based superalloy, LMSX-1, was examined. The results show that the tendency of the alloy to form all types of solidification defects decreased as the carbon content increased. The as-cast microstructures also exhibited a decrease in the amount of γ-γ' eutectic structure and an increase in the volume fraction of carbides and porosity, as the carbon content was increased. The carbides formed in these alloys were mostly of script-type MC carbides which formed continuous, dendritic networks in the interdendritic region. Microprobe analysis of the as-cast structures showed that the partitioning coefficients did not change with carbon additions. Therefore, the reduction in defect formation with increasing carbon content could not be attributed to changes in segregation behavior of alloying elements. Instead, the presence of these carbides in the interdendritic regions of the alloy appeared to have prevented the thermosolutal fluid flow

Quantitation of phosphorus excretion in sheep by compartmental analysis

International Nuclear Information System (INIS)

Schneider, K.M.; Boston, R.C.; Leaver, D.D.

1987-01-01

The control of phosphorus excretion in sheep has been examined by constructing a kinetic model that contains a mechanistic set of connections between blood and gastrointestinal tract. The model was developed using experimental data from chaff-fed sheep and gives an accurate description of the absorption and excretion of 32 P phosphorus in feces and urine of the ruminating sheep. These results indicated the main control site for phosphorus excretion in the ruminating sheep was the gastrointestinal tract, whereas for the non-ruminating sheep fed the liquid diet, control was exerted by the kidney. A critical factor in the induction of adaptation of phosphorus reabsorption by the kidney was the reduction in salivation, and since this response occurred independently of marked changes in the delivery of phosphorus to the kidney, a humoral factor may be involved in this communication between salivary gland and kidney

Metallurgical optimisation of PM superalloy N19

Directory of Open Access Journals (Sweden)

Locq Didier

2014-01-01

Full Text Available Microstructures of the new PM superalloy N19 have been investigated for various heat treatments in order to reach the best compromise between static strength and cyclic resistance. One subsolvus and several supersolvus heat treatments were applied to produce fine (7 μm and medium (25 μm grain sizes, respectively. The alloy is shown to be quite sensitive to the cooling conditions after solutioning as the γ′ hardening precipitates, both secondary and tertiary, have a direct influence on mechanical properties. Two cooling conditions after solutioning produce a high crack propagation resistance at 650 °C with dwell time cycles, which is one of the basic requirements. The low cycle fatigue behaviour appears to be correlated to the grain size, which determines the origin of crack initiation (from ceramic inclusions or not. The other mechanical properties (tensile, creep remain above target levels. Despite the medium size grain microstructure in the supersolvus condition, a high level of mechanical strength is observed in N19 at elevated temperature. It is understood that further improvement in properties can be achieved by developing coarse grain microstructures.

Effect of phytase supplementation on apparent phosphorus digestibility and phosphorus output in broiler chicks fed low-phosphorus diets

Directory of Open Access Journals (Sweden)

Xian-Ren Jiang

2015-04-01

Full Text Available This study was conducted to evaluate the effect of supplemental phytase in broiler chicks fed different low levels of total phosphorus (P on the apparent phosphorus digestibility (APD and phosphorus output (PO in the faeces and ileal digesta. After fed a standard broiler starter diet from day 0 to 14 post-hatch, a total of 144 male broiler chicks were allocated to 6 groups for a 7-d experiment with a 2 × 3 factorial design comparing phytase (supplemented without (CTR or with 400 FTU/kg phytase (PHY and total P levels (2.0, 2.5 and 3.0 g/kg. The faecal samples were collected from day 17 to 21 post-hatch. At 22 days of age, all the chicks were slaughtered and collected the ileal digesta. Phytase supplementation significantly (P < 0.01 increased APD and decreased PO in the faeces and ileal digesta in comparison with the CTR group. In addition, PO in the faeces expressed as g/kg DM diets and faeces (Diet × P level, P = 0.047 and < 0.01, respectively as well as PO in the ileal digesta expressed as g/kg DM digesta (Diet × P level, P = 0.04 were affected by diet and P level, which were due to the significant reduction (P < 0.01 by PHY supplementation to the diets with 3.0 g/kg total P. The results evidenced that supplemental phytase improved the APD and PO when chicks was fed 3.0 g/kg total P diet, while lower total P levels may limit exogenous phytase efficacy.

Mathematical modelling of brittle phase precipitation in complex ruthenium containing nickel-based superalloys

International Nuclear Information System (INIS)

Rettig, Ralf

2010-01-01

A new model has been developed in this work which is capable of simulating the precipitation kinetics of brittle phases, especially TCP-phases (topologically close packed phases) in ruthenium containing superalloys. The model simultaneously simulates the nucleation and the growth stage of precipitation for any number of precipitating phases. The CALPHAD method (Calculation of Phase Diagrams) is employed to calculate thermodynamic properties, such as the driving force or phase compositions in equilibrium. For calculation of diffusion coefficients, kinetic mobility databases which are also based on the CALPHAD-method are used. The model is fully capable of handling multicomponent effects, which are common in complex superalloys. Metastable phases can be treated and will automatically be dissolved if they get unstable. As the model is based on the general CALPHAD method, it can be applied to a broad range of precipitation processes in different alloys as long as the relevant thermodynamic and kinetic databases are available. The developed model proves that the TCP-phases precipitate in a sequence of phases. The first phase that is often formed is the metastable σ-phase because it has the lowest interface energy due to low-energy planes at the interface between matrix and precipitate. After several hundred hours the stable μ- and P-phases start to precipitate by nucleating at the σ-phase which is energetically favourable. During the growth of these stable phases the sigma-phase is continuously dissolved. It can be shown by thermodynamic CALPHAD calculations that the sigma-phase has a lower Gibbs free enthalpy than the μ- and P-phase. All required parameters of the model, such as interface energy and nucleate densities, have been estimated. The mechanisms of suppression of TCP-phase precipitation in the presence of ruthenium in superalloys were investigated with the newly developed model. It is shown by the simulations that ruthenium mostly affects the nucleation

Monitoring to assess progress toward meeting the Assabet River, Massachusetts, phosphorus total maximum daily load - Aquatic macrophyte biomass and sediment-phosphorus flux

Science.gov (United States)

Zimmerman, Marc J.; Qian, Yu; Yong Q., Tian

2011-01-01

In 2004, the Total Maximum Daily Load (TMDL) for Total Phosphorus in the Assabet River, Massachusetts, was approved by the U.S. Environmental Protection Agency. The goal of the TMDL was to decrease the concentrations of the nutrient phosphorus to mitigate some of the instream ecological effects of eutrophication on the river; these effects were, for the most part, direct consequences of the excessive growth of aquatic macrophytes. The primary instrument effecting lower concentrations of phosphorus was to be strict control of phosphorus releases from four major wastewatertreatment plants in Westborough, Marlborough, Hudson, and Maynard, Massachusetts. The improvements to be achieved from implementing this control were lower concentrations of total and dissolved phosphorus in the river, a 50-percent reduction in aquatic-plant biomass, a 30-percent reduction in episodes of dissolved oxygen supersaturation, no low-flow dissolved oxygen concentrations less than 5.0 milligrams per liter, and a 90-percent reduction in sediment releases of phosphorus to the overlying water. In 2007, the U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, initiated studies to evaluate conditions in the Assabet River prior to the upgrading of wastewater-treatment plants to remove more phosphorus from their effluents. The studies, completed in 2008, implemented a visual monitoring plan to evaluate the extent and biomass of the floating macrophyte Lemna minor (commonly known as lesser duckweed) in five impoundments and evaluated the potential for phosphorus flux from sediments in impounded and free-flowing reaches of the river. Hydrologically, the two study years 2007 and 2008 were quite different. In 2007, summer streamflows, although low, were higher than average, and in 2008, the flows were generally higher than in 2007. Visually, the effects of these streamflow differences on the distribution of Lemna were obvious. In 2007, large amounts of

Anaerobic fermentation combined with low-temperature thermal pretreatment for phosphorus-accumulating granular sludge: Release of carbon source and phosphorus as well as hydrogen production potential.

Science.gov (United States)

Zou, Jinte; Li, Yongmei

2016-10-01

Releases of organic compounds and phosphorus from phosphorus-accumulating granular sludge (PGS) and phosphorus-accumulating flocculent sludge (PFS) during low-temperature thermal pretreatment and anaerobic fermentation were investigated. Meanwhile, biogas production potential and microbial community structures were explored. The results indicate that much more soluble chemical oxygen demand (SCOD) and phosphorus were released from PGS than from PFS via low-temperature thermal pretreatment because of the higher extracellular polymeric substances (EPS) content in PGS and higher ratio of phosphorus reserved in EPS. Furthermore, PGS contains more anaerobes and dead cells, resulting in much higher SCOD and volatile fatty acids release from PGS than those from PFS during fermentation. PGS fermentation facilitated the n-butyric acid production, and PGS exhibited the hydrogen production potential during fermentation due to the presence of hydrogen-producing bacteria. Therefore, anaerobic fermentation combined with low-temperature thermal pretreatment can facilitate the recovery of carbon and phosphorus as well as producing hydrogen from PGS. Copyright © 2016 Elsevier Ltd. All rights reserved.

Phosphorus fertilizer and grazing management effects on phosphorus in runoff from dairy pastures.

Science.gov (United States)

Dougherty, Warwick J; Nicholls, Paul J; Milham, Paul J; Havilah, Euie J; Lawrie, Roy A

2008-01-01

Fertilizer phosphorus (P) and grazing-related factors can influence runoff P concentrations from grazed pastures. To investigate these effects, we monitored the concentrations of P in surface runoff from grazed dairy pasture plots (50 x 25 m) treated with four fertilizer P rates (0, 20, 40, and 80 kg ha(-1) yr(-1)) for 3.5 yr at Camden, New South Wales. Total P concentrations in runoff were high (0.86-11.13 mg L(-1)) even from the control plot (average 1.94 mg L(-1)). Phosphorus fertilizer significantly (P pasture biomass (P dairy pastures should be the maintenance of soil P at or near the agronomic optimum by the use of appropriate rates of P fertilizer.

Dietary phosphorus requirement of pejerrey fingerlings (Odontesthes bonariensis

Directory of Open Access Journals (Sweden)

Cleber Bastos Rocha

2014-02-01

Full Text Available To determine the available phosphorus requirement of pejerrey fish, four semi-purified diets were formulated to contain increasing available phosphorus levels (0.90, 2.7, 5.7 and 8.3 g/kg. Each diet was assigned to groups of 10 fish with average weight of 1.26±0.17 g, distributed into a completely randomized design with four treatments and four replications. Fish were fed at a rate of 10% total biomass four times a day for 60 days. The parameters productive performance, body chemical composition and mineral composition of bones and scales were evaluated. The best productive performance of fingerlings was obtained with the diet containing 4.3 g/kg available phosphorus. The average level of 6.3 g/kg available phosphorus promotes better mineralization of bones and scales in pejerrey fish.

Phosphorus Balance in Adolescent Girls and the Effect of Supplemental Dietary Calcium.

Science.gov (United States)

Vorland, Colby J; Martin, Berdine R; Weaver, Connie M; Peacock, Munro; Gallant, Kathleen M Hill

2018-03-01

There are limited data on phosphorus balance and the effect of dietary calcium supplements on phosphorus balance in adolescents. The purpose of this study was to determine phosphorus balance and the effect of increasing dietary calcium intake with a supplement on net phosphorus absorption and balance in healthy adolescent girls. This study utilized stored urine, fecal, and diet samples from a previously conducted study that focused on calcium balance. Eleven healthy girls ages 11 to 14 years participated in a randomized crossover study, which consisted of two 3-week periods of a controlled diet with low (817 ± 19.5 mg/d) or high (1418 ± 11.1 mg/d) calcium, separated by a 1-week washout period. Phosphorus intake was controlled at the same level during both placebo and calcium supplementation (1435 ± 23.5 and 1453 ± 28.0 mg/d, respectively, p = 0.611). Mean phosphorus balance was positive by about 200 mg/d and was unaffected by the calcium supplement ( p = 0.826). Urinary phosphorus excretion was lower with the calcium supplement (535 ± 42 versus 649 ± 41 mg/d, p = 0.013), but fecal phosphorus and net phosphorus absorption were not significantly different between placebo and calcium supplement (553 ± 60 versus 678 ± 63 versus mg/d, p = 0.143; 876 ± 62 versus 774 ± 64 mg/d, p = 0.231, respectively). Dietary phosphorus underestimates using a nutrient database compared with the content measured chemically from meal composites by ~40%. These results show that phosphorus balance is positive in girls during adolescent growth and that a calcium dietary supplement to near the current recommended level does not affect phosphorus balance when phosphorus intake is at 1400 mg/d, a typical US intake level. © 2017 American Society for Bone and Mineral Research.

Water Quality Criteria for White Phosphorus

Science.gov (United States)

1987-08-01

the number of eggs produced per adult , Chronic tests using inidges exposed to elemental phosphorus through contaminated sediments were also performed by...hemoglobinemia, hemoglobinuria, hematuria, bilirubinemia, mild (Cases 2 and 3) to severe (Case 1) hypocalcemia , -61- r. ., TABLE 14. SUMMARY OF CASUALTIES...day yellow phosphorus in corn oil for 30 days or less, lost weight. Young adult rats injected with 0.5 mg/kg/day lost less weight than fully mature or

Phosphorus availability and microbial respiration across biomes :  from plantation forest to tundra

OpenAIRE

Esberg, Camilla

2010-01-01

Phosphorus is the main limiting nutrient for plant growth in large areas of the world and the availability of phosphorus to plants and microbes can be strongly affected by soil properties. Even though the phosphorus cycle has been studied extensively, much remains unknown about the key processes governing phosphorus availability in different environments. In this thesis the complex dynamics of soil phosphorus and its availability were studied by relating various phosphorus fractions and soil ...

Genetics evaluation of phosphorus utilization in tropical cowpea ...

African Journals Online (AJOL)

Genetics evaluation of phosphorus utilization in tropical cowpea (Vigna ... that responds negatively to RP, using generation mean analysis of the parents, their ... was observed to be below the critical level, phosphorus uptake in the F1 and the ...

Synchrotron measurement of the 3D shape of X-ray reflections from the {gamma}/{gamma}{sup '}-microstructure of nickel-base superalloys

Energy Technology Data Exchange (ETDEWEB)

Epishin, Alexander; Link, Thomas; Ulbricht, Alexander; Bansal, Mamta [Technical Univ. of Berlin (Germany). Inst. of Material Science and Technology; Zizak, Ivo [Helmholtz-Zentrum Berlin for Materials and Energy BESSY II, Berlin (Germany)

2011-12-15

The 3D shape of X-ray reflections from the {gamma}/{gamma}{sup '}-microstructure of a nickel-base superalloy was investigated using synchrotron X-ray radiation and a position sensitive area detector. The measurements were performed on the 4{sup th} generation single-crystal nickel-base superalloy TMS138. The results show that X-ray reflections from non-cubic crystallographic planes have a complex 3D shape which changes during rafting. The 3D intensity distributions contain information about the spacing of the planes and their orientation as well. Whereas h00 reflections show the usual splitting into a {gamma}{sup '} and one {gamma}-subreflection, the hh0 and hhh reflections show two and three {gamma}-peaks respectively, resulting from the different types of {l_brace}100{r_brace} matrix channels. Therefore, these 3D diffraction measurements supply additional information about the spatial distribution of microstrains. (orig.)

Structural Performance of Inconel 625 Superalloy Brazed Joints

Science.gov (United States)

Chen, Jianqiang; Demers, Vincent; Cadotte, Eve-Line; Turner, Daniel; Bocher, Philippe

2017-02-01

The purpose of this work was to investigate tensile and fatigue behaviors of Inconel 625 superalloy brazed joints after transient liquid-phase bonding process. Brazing was performed in a vacuum furnace using a nickel-based filler metal in a form of paste to join wrought Inconel 625 plates. Mechanical tests were carried out on single-lap joints under various lap distance-to-thickness ratios. The fatigue crack initiation and crack growth modes were examined via metallographic analysis, and the effect of local stress on fatigue life was assessed by finite element simulations. The fatigue results show that fatigue strength and endurance limit increase with overlap distance, leading to a relatively large scatter of results. Fatigue cracks nucleated in the high-stressed region of the weld fillets from brittle eutectic phases or from internal brazing cavities. The present work proposes to rationalize the results by using the local stress at the brazing fillet. When using this local stress, all fatigue-obtained results find themselves on a single S- N curve, providing a design curve for any joint configuration in fatigue solicitation.

Bloodcompatibility improvement of titanium oxide film modified by phosphorus ion implantation

International Nuclear Information System (INIS)

Yang, P.; Leng, Y.X.; Zhao, A.S.; Zhou, H.F.; Xu, L.X.; Hong, S.; Huang, N.

2006-01-01

Our recent investigation suggested that Ti-O thin film could be a newly developed antithrombotic material and its thromboresistance could be related to its physical properties of wide gap semiconductor. In this work, titanium oxide film was modified by phosphorus ion implantation and succeeding vacuum annealing. RBS were used to investigate phosphorus distribution profile. Contact angle test results show that phosphorus-doped titanium oxide film becomes more hydrophilic after higher temperature annealing, while its electric conductivity increases. Antithrombotic property of phosphorus-doped titanium oxide thin films was examined by clotting time and platelet adhesion tests. The results suggest that phosphorus doping is an effective way to improve the bloodcompatibility of titanium oxide film, and it is related to the changes of electron structure and surface properties caused by phosphorus doping

Fractions and Distribution of Phosphorus in Sediments of the Yarlung Zangbo River Basin

Science.gov (United States)

Huang, W.; An, R.; Huang, Y.; Pu, X.; Li, R.; Li, J.

2017-12-01

The Yarlung Zangbo River is one of the highest rivers in the world. The ecological environment of the river basin has its specificity. It locates in the remote area of China, and the ecological environment is very fragile. The fundamental data of phosphorus content in sediments of the Yarlung Zangbo River Basin are very scarce. In order to clarify the distribution law of phosphorus in the sediments of this area and provide the fundamental data for the study of phosphorus transport in the Yarlung Zangbo River, the authors collected the sediment samples from the mainstream and its tributaries in the research area. Their particle size distributions, specific surface areas, contents of total phosphorus, organic phosphorus and different forms of inorganic phosphorus were analyzed. Then, the fractions and spatial distribution of these forms phosphorus were studied. The results showed that the fractions and distribution characteristics of phosphorus in each form are significant different in the sediments of the Yarlung Zangbo River. The phosphorus contents in the soil erosion deposits and river bed sediment samples are also different. The phosphorus content in sediment is significantly correlated with the sediment characteristics. Keywords: the Yarlung Zangbo River; sediments; fractions of phosphorus; distribution characteristics

The release of dissolved phosphorus from lake sediments

NARCIS (Netherlands)

Boers, P.C.M.

1991-01-01

Chapter 1. Introduction: Eutrophication is one of the world's major water quality problems. Attempts to alleviate eutrophication of lakes have involved the control of phosphorus loadings. In such cases, an internal loading of phosphorus from the sediments may

Phase-field simulation of microstructure evolution in Ni-based superalloys

Energy Technology Data Exchange (ETDEWEB)

Tsukada, Yuhki; Murata, Yoshinori; Morinaga, Masahiko [Nagoya Univ. (Japan). Dept. of Materials, Physics and Energy Engineering; Koyama, Toshiyuki [National Institute for Materials Science, Tsukuba, Ibaraki (Japan)

2010-07-01

The morphological evolution of the ({gamma} + {gamma}') microstructure in Ni-based superalloys is investigated by a series of phase-field simulations. In the simulation for simple aging heat treatment, the effect of elastic constant inhomogeneity between the {gamma} and {gamma}' phases is investigated. The elastic anisotropy or the shear modulus is changed independently in the simulation. The variation of the anisotropy affects the morphology, particle size distribution and coarsening kinetics of the {gamma}' phase, whereas the variation of the shear modulus does not affect them. In the simulation for high temperature creep, formation and collapse of the rafted structure are reproduced under the assumption that the creep strain in the {gamma} matrix increases with creep time. This morphological evolution is related to the change in the energetically stable morphology of the {gamma}' phase with increasing the creep strain. (orig.)

N18, powder metallurgy superalloy for disks: Development and applications

Energy Technology Data Exchange (ETDEWEB)

Guedou, J.Y.; Lautridou, J.C.; Honnorat, Y. (SNECMA, Evry (France). Materials and Processes Dept.)

1993-08-01

The preliminary industrial development of a powder metallurgy (PM) superalloy, designated N18, for disk applications has been completed. This alloy exhibits good overall mechanical properties after appropriate processing of the material. These properties have been measured on both isothermally forged and extruded billets, as well as on specimens cut from actual parts. The temperature capability of the alloy is about 700 C for long-term applications and approximately 750 C for short-term use because of microstructural instability. Further improvements in creep and crack propagation properties, without significant reduction in tensile strength, are possible through appropriate thermomechanical processing, which results in a large controlled grain size. Spin pit tests on subscale disks have confirmed that the N18 alloy has a higher resistance than PM Astrology and is therefore an excellent alloy for modern turbine disk applications.

Discussion of "Investigation of Oxide Bifilms in Investment Cast Superalloy IN100 Parts I and II"*

Science.gov (United States)

Campbell, John

2017-10-01

Fuchs and Kaplan carried out experiments in an attempt to ascertain whether oxide bifilms were present in a vacuum-cast Ni-base superalloy but concluded negatively. Although this author challenged their interpretation of their findings, both parties had overlooked the presence in the alloy of boron which is now known to inhibit bifilm formation. However, even though boron can help significantly, improved filling system designs remain important if other damaging entrainment defects are to be avoided.

Studies on the Corrosion Resistance of Laser-Welded Inconel 600 and Inconel 625 Nickel-Based Superalloys

Directory of Open Access Journals (Sweden)

Łyczkowska K.

2017-06-01

Full Text Available The paper presents the results of the electrochemical corrosion tests of Inconel 600 and Inconel 625 laser-welded superalloys. The studies were conducted in order to assess the resistance to general and pitting corrosion in 3.5% NaCl solution. It was found that Inconel 600 possesses good corrosion resistance, however Inconel 625 is characterized by a greater resistance to general and also to pitting corrosion of the weld as well as the base metal.

Phosphorus Uptake and Partitioning in Maize as Affected by Tillage ...

African Journals Online (AJOL)

Higher phosphorus concentrations were found in the ears than in the shoots and leaves at physiological maturity. Tillage x phospho-rus interactions influenced phosphorus partitioning in the ears and the leaves on the Dystric Cam-bisol but not on the Ferric Acrisol. PUE in the plant parts were significantly higher under ...

Kinetics of Grain Growth in 718 Ni-Base Superalloy

Directory of Open Access Journals (Sweden)

Huda Z.

2014-10-01

Full Text Available The Haynes® 718 Ni-base superalloy has been investigated by use of modern material characterization, metallographic and heat treatment equipment. Grain growth annealing experiments at temperatures in the range of 1050 – 1200 oC (1323–1473K for time durations in the range of 20 min-22h have been conducted. The kinetic equations and an Arrhenius-type equation have been applied to compute the grain-growth exponent n and the activation energy for grain growth, Qg, for the investigated alloy. The grain growth exponent, n, was computed to be in the range of 0.066-0.206; and the n values have been critically discussed in relation to the literature. The activation energy for grain growth, Qg, for the investigated alloy has been computed to be around 440 kJ/mol; and the Qg data for the investigated alloy has been compared with other metals and alloys and ceramics; and critically analyzed in relation to our results.

ISOTHERMAL AND THERMOMECHANICAL FATIGUE OF A NICKEL-BASE SUPERALLOY

Directory of Open Access Journals (Sweden)

Carlos Carvalho Engler-Pinto Júnior

2014-06-01

Full Text Available Thermal gradients arising during transient regimes of start-up and shutdown operations produce a complex thermal and mechanical fatigue loading which limits the life of turbine blades and other engine components operating at high temperatures. More accurate and reliable assessment under non-isothermal fatigue becomes therefore mandatory. This paper investigates the nickel base superalloy CM 247LC-DS under isothermal low cycle fatigue (LCF and thermomechanical fatigue (TMF. Test temperatures range from 600°C to 1,000°C. The behavior of the alloy is strongly affected by the temperature variation, especially in the 800°C-1,000°C range. The Ramberg-Osgood equation fits very well the observed isothermal behavior for the whole temperature range. The simplified non-isothermal stress-strain model based on linear plasticity proposed to represent the thermo-mechanical fatigue behavior was able to reproduce the observed behavior for both in-phase and out-of-phase TMF cycling.

Black Phosphorus: Critical Review and Potential for Water Splitting Photocatalyst

Directory of Open Access Journals (Sweden)

Tae Hyung Lee

2016-10-01

Full Text Available A century after its first synthesis in 1914, black phosphorus has been attracting significant attention as a promising two-dimensional material in recent years due to its unique properties. Nowadays, with the development of its exfoliation method, there are extensive applications of black phosphorus in transistors, batteries and optoelectronics. Though, because of its hardship in mass production and stability problems, the potential of the black phosphorus in various fields is left unexplored. Here, we provide a comprehensive review of crystal structure, electronic, optical properties and synthesis of black phosphorus. Recent research works about the applications of black phosphorus is summarized. Among them, the possibility of black phosphorous as a solar water splitting photocatalyst is mainly discussed and the feasible novel structure of photocatalysts based on black phosphorous is proposed.

Global Fertilizer and Manure, Version 1: Phosphorus Fertilizer Application

Data.gov (United States)

National Aeronautics and Space Administration — The Phosphorus Fertilizer Application dataset of the Global Fertilizer and Manure, Version 1 Data Collection represents the amount of phosphorus fertilizer nutrients...

Dietary phosphorus excess: a risk factor in chronic bone, kidney, and cardiovascular disease?

Science.gov (United States)

Uribarri, Jaime; Calvo, Mona S

2013-09-01

There is growing evidence in the nephrology literature supporting the deleterious health effect of excess dietary phosphorus intake. This issue has largely escaped the attention of nutrition experts until this symposium, which raised the question of whether the same health concerns should be extended to the general population. The potential hazard of a high phosphorus intake in the healthy population is illustrated by findings from acute and epidemiologic studies. Acute studies in healthy young adults demonstrate that phosphorus intakes in excess of nutrient needs may significantly disrupt the hormonal regulation of phosphorus contributing to disordered mineral metabolism, vascular calcification, bone loss, and impaired kidney function. One of the hormonal factors acutely affected by dietary phosphorus loading is fibroblast growth factor-23, which may be a key factor responsible for many of the cardiovascular disease (CVD) complications of high phosphorus intake. Increasingly, large epidemiological studies suggest that mild elevations of serum phosphorus within the normal range are associated with CVD risk in healthy populations. Few population studies link high dietary phosphorus intake to mild changes in serum phosphorus due to study design issues specific to phosphorus and inaccurate nutrient composition databases. The increasing phosphorus intake due to the use of phosphorus-containing ingredients in processed food and the growing consumption of processed convenience and fast foods is an important factor that needs to be emphasized.

On the thermal cyclic loading behaviour of a directional eutectic superalloy based on the Co-Cr-C system

International Nuclear Information System (INIS)

Hildebrandt, U.W.; Nicoll, A.R.

1981-01-01

Various modifications of the eutectic, directionally solidified superalloy 73 C were investigated with respect to creep fatigue effects. This was carried out using a thermal cycling apparatus where a mechanical uniaxial load could be applied. A high volume fraction of carbides had an impairing effect on fatigue life. An improvement, however, could be obtained using low concentrations of refractory elements which form monocarbides. (orig.) [de

A representation of the phosphorus cycle for ORCHIDEE (revision 4520)

Science.gov (United States)

Goll, Daniel S.; Vuichard, Nicolas; Maignan, Fabienne; Jornet-Puig, Albert; Sardans, Jordi; Violette, Aurelie; Peng, Shushi; Sun, Yan; Kvakic, Marko; Guimberteau, Matthieu; Guenet, Bertrand; Zaehle, Soenke; Penuelas, Josep; Janssens, Ivan; Ciais, Philippe

2017-10-01

Land surface models rarely incorporate the terrestrial phosphorus cycle and its interactions with the carbon cycle, despite the extensive scientific debate about the importance of nitrogen and phosphorus supply for future land carbon uptake. We describe a representation of the terrestrial phosphorus cycle for the ORCHIDEE land surface model, and evaluate it with data from nutrient manipulation experiments along a soil formation chronosequence in Hawaii. ORCHIDEE accounts for the influence of the nutritional state of vegetation on tissue nutrient concentrations, photosynthesis, plant growth, biomass allocation, biochemical (phosphatase-mediated) mineralization, and biological nitrogen fixation. Changes in the nutrient content (quality) of litter affect the carbon use efficiency of decomposition and in return the nutrient availability to vegetation. The model explicitly accounts for root zone depletion of phosphorus as a function of root phosphorus uptake and phosphorus transport from the soil to the root surface. The model captures the observed differences in the foliage stoichiometry of vegetation between an early (300-year) and a late (4.1 Myr) stage of soil development. The contrasting sensitivities of net primary productivity to the addition of either nitrogen, phosphorus, or both among sites are in general reproduced by the model. As observed, the model simulates a preferential stimulation of leaf level productivity when nitrogen stress is alleviated, while leaf level productivity and leaf area index are stimulated equally when phosphorus stress is alleviated. The nutrient use efficiencies in the model are lower than observed primarily due to biases in the nutrient content and turnover of woody biomass. We conclude that ORCHIDEE is able to reproduce the shift from nitrogen to phosphorus limited net primary productivity along the soil development chronosequence, as well as the contrasting responses of net primary productivity to nutrient addition.

Effect of processing on microstructure and physical properties of three nickel-based superalloys with different hardening mechanisms

Energy Technology Data Exchange (ETDEWEB)

Strondl, Annika; Frommeyer, Georg [Department of Materials Technology, Max-Planck-Institut fuer Eisenforschung GmbH, Max-Planck-Strasse 1, D-40237 Duesseldorf (Germany); Klement, Uta [Department of Materials and Manufacturing Technology, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Milenkovic, Srdjan; Schneider, Andre

2012-07-15

The nickel-based superalloys Inconel alloy 600, Udimet alloy 720, and Inconel alloy 718 were produced by electron beam melting (EBM), casting, and directional solidification (DS). The distance between dendrites and the size of the precipitates indicated the difference in solidification rates between the three processes. In this study, the solidification rate was fastest with EBM, closely followed by casting, whereas it was much slower with DS. In the directional solidified materials the <100> direction was the fastest and thus, preferred growth direction. The EBM samples show a sharp (001)[100] texture in the building direction and in the two scanning directions of the electron beam. Macrosegregation was observed in some cast and directionally solidified samples, but not in the EBM samples. The melting temperatures are in good agreement with literature and the narrow melting interval of IN600 compare to UD720 and IN718 might reduce the risk of incipient melting during EBM processing. Porosity was observed in the EBM samples and the reasons are discussed. However, EBM seems to be a feasible process route to produce nickel-based superalloys with well-defined texture, no macrosegregation and a rapidly solidified microstructure. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Erosion-corrosion behaviour of Ni-based superalloy Superni-75 in the real service environment of the boiler

Energy Technology Data Exchange (ETDEWEB)

Sidhu, T.S.; Prakash, S.; Agrawal, R.D.; Bhagat, R. [Shaheed Bhagat Singh College of Engineering & Technology, Ferozepur (India)

2009-04-15

The super-heater and re-heater tubes of the boilers used in thermal power plants are subjected to unacceptable levels of surface degradation by the combined effect of erosion-corrosion mechanism, resulting in the tube wall thinning and premature failure. The nickel-based superalloys can be used as boiler tube materials to increase the service life of the boilers, especially for the new generation ultra-supercritical boilers. The aim of the present investigation is to evaluate the erosion-corrosion behaviour of Ni-based superalloy Superni-75 in the real service environment of the coal-fired boiler of a thermal power plant. The cyclic experimental study was performed for 1000 h in the platen superheater zone of the coal-fired boiler where the temperature was around 900{sup o}C. The corrosion products have been characterized with respect to surface morphology, phase composition and element concentration using the combined techniques of X-ray diffractometry (XRD), scanning electron microscopy/energy-dispersive analysis (SEM/EDAX) and electron probe micro analyser (EPMA). The Superni-75 performed well in the coal-fired boiler environment, which has been attributed mainly to the formation of a thick band of chromium in scale due to selective oxidation of the chromium.

Additive Manufacturing of IN100 Superalloy Through Scanning Laser Epitaxy for Turbine Engine Hot-Section Component Repair: Process Development, Modeling, Microstructural Characterization, and Process Control

Science.gov (United States)

Acharya, Ranadip; Das, Suman

2015-09-01

This article describes additive manufacturing (AM) of IN100, a high gamma-prime nickel-based superalloy, through scanning laser epitaxy (SLE), aimed at the creation of thick deposits onto like-chemistry substrates for enabling repair of turbine engine hot-section components. SLE is a metal powder bed-based laser AM technology developed for nickel-base superalloys with equiaxed, directionally solidified, and single-crystal microstructural morphologies. Here, we combine process modeling, statistical design-of-experiments (DoE), and microstructural characterization to demonstrate fully metallurgically bonded, crack-free and dense deposits exceeding 1000 μm of SLE-processed IN100 powder onto IN100 cast substrates produced in a single pass. A combined thermal-fluid flow-solidification model of the SLE process compliments DoE-based process development. A customized quantitative metallography technique analyzes digital cross-sectional micrographs and extracts various microstructural parameters, enabling process model validation and process parameter optimization. Microindentation measurements show an increase in the hardness by 10 pct in the deposit region compared to the cast substrate due to microstructural refinement. The results illustrate one of the very few successes reported for the crack-free deposition of IN100, a notoriously "non-weldable" hot-section alloy, thus establishing the potential of SLE as an AM method suitable for hot-section component repair and for future new-make components in high gamma-prime containing crack-prone nickel-based superalloys.

Physicochemical properties of mixed phosphorus halides

International Nuclear Information System (INIS)

Sladkov, I.B.; Tugarinova, N.S.

1996-01-01

Certain physicochemical properties (thermodynamic characteristics at boiling point, critical constants, density of liquid on the saturation line) of mixed phosphorus halides (PI 3 , PI 2 F, PIF 2 , PI 2 Cl, PICl 2 , PI 1 Br, PIBr 2 , PIClF, PIBrCl, etc.) are determined by means of approximate methods. Reliability of the results obtained is confirmed by comparison of calculated and experimental data for phosphorus compounds of the same type. 7 refs., 3 figs., 4 tabs

Further developments and field deployment of phosphorus functionalized polymeric scale inhibitors

Energy Technology Data Exchange (ETDEWEB)

Todd, Malcolm J.; Thornton, Alex R.; Wylde, Jonathan J.; Strachan, Catherine J.; Moir, Gordon [Clariant Oil Services, Muttenz (Switzerland); Goulding, John [John Goulding Consultancy, York (United Kingdom)

2012-07-01

As the oil and gas industry strives to replace ageing, environmentally undesirable scale inhibitors there is an ever increasing use of polymeric inhibitors. The incorporation of phosphorous functionality into a polymer backbone has been shown to improve inhibition efficiency, enhance adsorption characteristics and allow the polymer concentration to be analyzed by elemental phosphorus. It is known that some phosphorus tagged polymers can be problematic to analyze in oil field brines as they typically have a low phosphorus content which is difficult to determine from the background. The development of novel phosphorus functionalized polymeric scale inhibitors was previously described (IBP3530-10). This paper follows the development of the inhibitor class. Utilizing extensive laboratory testing the interactive nature of the scale inhibitors and reservoir lithology was studied. These novel phosphorus functionalized inhibitors were compared to a number of other available scale inhibitors. The incorporation of phosphorus functionality into polymeric inhibitors can be expensive utilizing traditional methods as the phosphorus containing monomers are the financially limiting factor. These are typically vinyl phosphonic acid (VPA), or vinyl diphosphonic acid (VDPA). The novel phosphorus functionalized monomers utilized herein are simpler to manufacture allowing higher phosphorus content within the polymer backbone. The addition of phosphorus into a polymer backbone has previously been known to exacerbate analysis issues in some commercially available scale inhibitors. This is due to incomplete polymerization reactions leaving free and/or inorganic phosphorus containing moieties which can interfere with the analysis, or low levels of phosphorus within end-capped polymers can make it difficult to determine the active concentration accurately within field brines which contain many impuritie. Polymeric inhibitors are known to contain a range of molecular weights with varying

Ethylene: a regulator of root architectural responses to soil phosphorus availability

NARCIS (Netherlands)

Borch, K.; Bouma, T.J.; Lynch, J.P.; Brown, K.M.

1999-01-01

The involvement of ethylene in root architectural responses to phosphorus availability was investigated in common bean (Phaseolus vulgaris L,) plants grown with sufficient and deficient phosphorus. Although phosphorus deficiency reduced root mass and lateral root number, main root length was

Experimental study of micro-milling mechanism and surface quality of a nickel-based single crystal superalloy

Energy Technology Data Exchange (ETDEWEB)

Gao, Qi; Gong, Yadong; Zhou, Yun Guang; Wen, Xue Long [School of Mechanical Engineering and Automation, Northeastern University, Shenyang (China)

2017-01-15

Micro-milling is widely used as a method for machining of micro-parts with high precision and efficiency. Taking the nickel-based single-crystal superalloy DD98 as the research object, the crystal characteristics of single-crystal materials were analysed, and the removal mechanism of single-crystal micro-milled parts was described. Based on molecular dynamics, a simulation model for nickel-based single-crystal superalloy DD98 micro-milling was established. Based on the response surface method of central composite design, the influences of spindle speed, feed rate, and milling depth on the surface roughness were examined, and a second-order regression model of the DD98 surface roughness was established. Using analysis of variance and the residuals of the model, a significant influence on surface roughness was found in the following order from large to small: Feed rate, spindle speed, and milling depth. Comparisons were conducted between the micro-milling experimental values and the predicted model values for different process parameters. The results show that the model fit is relatively high, and the adaptability is good. Scanning electron microscopy analysis of the micro-milling surfaces was performed to verify the slip and the removal mechanism of single-crystal materials. These results offer a theoretical reference and experimental basis for micro-milling of single-crystal materials.

Control of microstructure and mechanical properties of laser solid formed Inconel 718 superalloy by electromagnetic stirring

Science.gov (United States)

Liu, Fencheng; Cheng, Hongmao; Yu, Xiaobin; Yang, Guang; Huang, Chunping; Lin, Xin; Chen, Jing

2018-02-01

The coarse columnar grains and special interface in laser solid formed (LSFed) Inconel 718 superalloy workpieces seriously affect their mechanical properties. To improve the microstructure and mechanical properties of LSFed Inconel 718 superalloy, electromagnetic stirring (EMS) was introduced to alter the solidification process of the molten pool during LSF. The results show that EMS could not completely eliminate the epitaxially growing columnar grains, however, the strong convection of liquid metals can effectively influence the solid-liquid interface growing mode. The segregation of alloying elements on the front of solid-liquid interface is inhibited and the degree of constitutional supercooling decreases correspondingly. Comparing the microstructures of samples formed under different process parameters, the size and amount of the γ+Laves eutectic phases formed in interdendritic area decrease along with the increasing magnetic field intensity, resulting in more uniformly distributed alloying elements. The residual stress distribution is proved to be more uniform, which is beneficial to the grain refinement after recrystallilzaiton. Mechanical properties testing results show an improvement of 100 MPa in tensile strength and 22% in elongation was obtained after EMS was used. The high cycle fatigue properties at room temperature was also improved from 4.09 × 104 cycles to 8.21 × 104 cycles for the as-deposited samples, and from 5.45 × 104 cycles to 12.73 × 104 cycles for the heat treated samples respectively.

Fatigue Resistance of the Grain Size Transition Zone in a Dual Microstructure Superalloy Disk

Science.gov (United States)

Gabb, T. P.; Kantzos, P. T.; Telesman, J.; Gayda, J.; Sudbrack, C. K.; Palsa, B. S.

2010-01-01

Mechanical property requirements vary with location in nickel-based superalloy disks. To maximize the associated mechanical properties, heat treatment methods have been developed for producing tailored microstructures. In this study, a specialized heat treatment method was applied to produce varying grain microstructures from the bore to the rim portions of a powder metallurgy processed nickel-based superalloy disk. The bore of the contoured disk consisted of fine grains to maximize strength and fatigue resistance at lower temperatures. The rim microstructure of the disk consisted of coarse grains for maximum resistance to creep and dwell crack growth at high temperatures up to 704 C. However, the fatigue resistance of the grain size transition zone was unclear, and needed to be evaluated. This zone was located as a band in the disk web between the bore and rim. Specimens were extracted parallel and transverse to the transition zone, and multiple fatigue tests were performed at 427 and 704 C. Mean fatigue lives were lower at 427 C than for 704 C. Specimen failures often initiated at relatively large grains, which failed on crystallographic facets. Grain size distributions were characterized in the specimens, and related to the grains initiating failures as well as location within the transition zone. Fatigue life decreased with increasing maximum grain size. Correspondingly, mean fatigue resistance of the transition zone was slightly higher than that of the rim, but lower than that of the bore. The scatter in limited tests of replicates was comparable for all transition zone locations examined.

Sintering and microstructure evolution of columnar nickel-based superalloy sheets prepared by EB-PVD

International Nuclear Information System (INIS)

Chen, S.; Qu, S.J.; Liang, J.; Han, J.C.

2010-01-01

Research highlights: → EB-PVD technology is commonly used to deposit thermal barrier coatings (TBCs) and columnar structure is commonly seen in EB-PVD condensates. The unique columnar structure can provide outstanding resistance against thermal shock and mechanical strains for TBCs. However, a number of researchers have found that the columnar structure can affect the mechanical properties of EB-PVD alloy thin sheet significantly. As yet, works on how to reduce this kind of effects are seldom done. In the present article, we tried to reveal the sintering effects on microstructure evolution and mechanical properties of columnar Ni-based superalloy sheet. The results suggests that after sintering, the columnar structure degrades. Degradation depends on sintering temperature and time. Both the ultimate tensile strength and the elongation percentage are effectively improved after sintering. - Abstract: A ∼0.15 mm-thick columnar nickel-based superalloy sheet was obtained by electron beam physical vapor deposition (EB-PVD). The as-deposited alloy sheet was sintered at different conditions. The microstructure of the specimens before and after sintering was characterized by using scanning electron microscopy. An X'Pert texture facility was used to determine the crystallographic orientation of the as-deposited alloy sheet. The phase transformation was investigated by X-ray diffraction. Tensile tests were conducted at room temperature on as-deposited and sintered specimens. The results show that the as-deposited sheet is composed of typical columnar structures. After sintering, however, the columnar structure degrades. The degradation depends on sintering temperature and time. Both the ultimate tensile strength and the elongation percentage are effectively improved after sintering.

Phosphorus and groundwater: Establishing links between agricultural use and transport to streams

Science.gov (United States)

Domagalski, Joseph L.; Johnson, Henry

2012-01-01

Phosphorus is a highly reactive element that is essential for life and forms a variety of compounds in terrestrial and aquatic ecosystems. In water, phosphorus may be present as the orthophosphate ion (PO43-) and is also present in all life forms as an essential component of cellular material. In natural ecosystems, phosphorus is derived from the erosion of rocks and is conserved for plant growth as it is returned to the soil through animal waste and the decomposition of plant and animal tissue; but in agricultural systems, a portion of the phosphorus is removed with each harvest, especially since phosphorus is concentrated in the seeds and fruit. Phosphorus is added to soil by using chemical fertilizers, manure, and composted materials. Agricultural use of chemical phosphorus fertilizer, in the United States, in 2008 was 4,247,000 tons, which is an increase of 25 percent since 1964 (http://www.ers.usda.gov/Data/FertilizerUse/). Widely grown corn, soybeans, and wheat use the greatest amount of phosphorus fertilizer among agricultural crops.

Simultaneous nitrogen and phosphorus removal in the sulfur cycle-associated Enhanced Biological Phosphorus Removal (EBPR) process.

Science.gov (United States)

Wu, Di; Ekama, George A; Wang, Hai-Guang; Wei, Li; Lu, Hui; Chui, Ho-Kwong; Liu, Wen-Tso; Brdjanovic, Damir; van Loosdrecht, Mark C M; Chen, Guang-Hao

2014-02-01

Hong Kong has practiced seawater toilet flushing since 1958, saving 750,000 m(3) of freshwater every day. A high sulfate-to-COD ratio (>1.25 mg SO4(2-)/mg COD) in the saline sewage resulting from this practice has enabled us to develop the Sulfate reduction, Autotrophic denitrification and Nitrification Integrated (SANI(®)) process with minimal sludge production and oxygen demand. Recently, the SANI(®) process has been expanded to include Enhanced Biological Phosphorus Removal (EBPR) in an alternating anaerobic/limited-oxygen (LOS-EBPR) aerobic sequencing batch reactor (SBR). This paper presents further development - an anaerobic/anoxic denitrifying sulfur cycle-associated EBPR, named as DS-EBPR, bioprocess in an alternating anaerobic/anoxic SBR for simultaneous removal of organics, nitrogen and phosphorus. The 211 day SBR operation confirmed the sulfur cycle-associated biological phosphorus uptake utilizing nitrate as electron acceptor. This new bioprocess cannot only reduce operation time but also enhance volumetric loading of SBR compared with the LOS-EBPR. The DS-EBPR process performed well at high temperatures of 30 °C and a high salinity of 20% seawater. A synergistic relationship may exist between sulfur cycle and biological phosphorus removal as the optimal ratio of P-release to SO4(2-)-reduction is close to 1.0 mg P/mg S. There were no conventional PAOs in the sludge. Copyright © 2013 Elsevier Ltd. All rights reserved.

Regulation of phosphorus uptake and utilization: transitioning from current knowledge to practical strategies.

Science.gov (United States)

Hasan, Md Mahmudul; Hasan, Md Mainul; Teixeira da Silva, Jaime A; Li, Xuexian

2016-01-01

Phosphorus is a poorly bioavailable macronutrient that is essential for crop growth and yield. Overuse of phosphorus fertilizers results in low phosphorus use efficiency (PUE), has serious environmental consequences and accelerates the depletion of phosphorus mineral reserves. It has become extremely challenging to improve PUE while preserving global food supplies and maintaining environmental sustainability. Molecular and genetic analyses have revealed the primary mechanisms of phosphorus uptake and utilization and their relationships to phosphorus transporters, regulators, root architecture, metabolic adaptations, quantitative trait loci, hormonal signaling and microRNA. The ability to improve PUE requires a transition from this knowledge of molecular mechanisms and plant architecture to practical strategies. These could include: i) the use of arbuscular mycorrhizal fungal symbioses for efficient phosphorus mining and uptake; ii) intercropping with suitable crop species to achieve phosphorus activation and mobilization in the soil; and iii) tissue-specific overexpression of homologous genes with advantageous agronomic properties for higher PUE along with breeding for phosphorus-efficient varieties and introgression of key quantitative trait loci. More effort is required to further dissect the mechanisms controlling phosphorus uptake and utilization within plants and provide new insight into the means to efficiently improve PUE.

Determination of phosphorus in gold or silver brazing alloys

International Nuclear Information System (INIS)

Antepenko, R.J.

1976-01-01

A spectrophotometric method has been devised for measuring microgram levels of phosphorus in brazing alloys of gold or silver alloys is normally measured by solid mass spectrometry, but the high nickel concentration produces a double ionized nickel spectral interference. The described procedures is based upon the formation of molybdovandophosphoric acid when a molybdate solution is added to an acidic solution containing orthophosphate and vanadate ions. The optimum acidity for forming the yellow colored product is 0.5 N hydrochloric acid. The working concentration range is from 0.1 to 1 ppm phosphorus using 100-mm cells and measuring the absorbance at 460 nm. The sample preparation procedure employs aqua regia to dissolve the alloy oxidize the phosphorus to orthophosphate. Cation-exchange chromatography is used to remove nickel ions and anion-exchange and chromatography to remove gold ions as the chloride complex. Excellent recoveries are obtained for standard phosphorus solutions run through the sample procedure. The procedure is applicable to a variety of gold or silver braze alloys requiring phosphorus analysis

Selenium and phosphorus interaction in pea (pisum sativum L.)

International Nuclear Information System (INIS)

Singh, Mahendra; Bhandari, D.K.

1975-01-01

The interaction of selenium and phosphorus on the dry matter yield and concentration and uptake of phosphorus, sulfur and selenium was studied in pea (Pisum sativnum) var. T 163. The fertilizer was tagged with P 32 . It was observed that increased concentration of applied selenium in soil decreased the dry matter yield and increased the concentration and uptake of total P, soil P and selenium in pea plants. Increased concentration of P alone increased dry matter yield, concentration and uptake of total, soil and fertilizer P and selenium which was beyond safe limits, and decreased concentration and uptake of sulphur. Selenium and phosphorus showed strong synergetic relationship by increasing the concentration of each other in plants while both showed antagonistic effect on the concentration of sulphur. Phosphorus compensated the toxic effect of selenium and improved the growth and dry matter yield of pea plants. The highest selenium concentration of 22.4 ppm was observed in 100 ppm phosphorus with 5 ppm selenium treated pots while lowest (0.10 ppm) in control. (author)

Biological nitrogen and phosphorus removal by filamentous bacteria ...

African Journals Online (AJOL)

The availability of excess nutrients (phosphorus (P) and nitrogen (N)) in wastewater systems causes many water quality problems. These problems include eutrophication whereby algae grow excessively and lead to depletion of oxygen, death of the aquatic life and bad odours. Biological phosphorus removal has gained ...

Phosphorus Processing—Potentials for Higher Efficiency

OpenAIRE

Ludwig Hermann; Fabian Kraus; Ralf Hermann

2018-01-01

In the aftermath of the adoption of the Sustainable Development Goals (SDGs) and the Paris Agreement (COP21) by virtually all United Nations, producing more with less is imperative. In this context, phosphorus processing, despite its high efficiency compared to other steps in the value chain, needs to be revisited by science and industry. During processing, phosphorus is lost to phosphogypsum, disposed of in stacks globally piling up to 3–4 billion tons and growing by about 200 million ...

Regulation of phosphorus uptake and utilization: transitioning from current knowledge to practical strategies

OpenAIRE

Hasan, Md. Mahmudul; Hasan, Md. Mainul; Teixeira da Silva, Jaime A.; Li, Xuexian

2016-01-01

Phosphorus is a poorly bioavailable macronutrient that is essential for crop growth and yield. Overuse of phosphorus fertilizers results in low phosphorus use efficiency (PUE), has serious environmental consequences and accelerates the depletion of phosphorus mineral reserves. It has become extremely challenging to improve PUE while preserving global food supplies and maintaining environmental sustainability. Molecular and genetic analyses have revealed the primary mechanisms of phosphorus up...

Phosphorus-defect interactions during thermal annealing of ion implanted silicon

Science.gov (United States)

Keys, Patrick Henry

Ion implantation of dopant atoms into silicon generates nonequilibrium levels of crystal defects that can lead to the detrimental effects of transient enhanced diffusion (TED), incomplete dopant activation, and p-n junction leakage. In order to control these effects, it is vital to have a clear understanding of dopant-defect interactions and develop models that account for these interactions. This research focuses on experimentally investigating and modeling the clustering of phosphorus dopant atoms with silicon interstitials. Damage recovery of 40keV Si+ implants in phosphorus doped wells is experimentally analyzed. The effects of background phosphorus concentration, self implant dose, and anneal temperature are investigated. Phosphorus concentrations ranging from 2.0 x 1017 to 4.0 x 1019 cm-3 and Si+ doses ranging from 5.0 x 1013 cm-2 to 2.0 x 1014 cm-2 are studied during 650-800°C anneals. A dramatic reduction in the number of interstitials bound in {311} defects with increasing phosphorus background concentration is observed. It is suggested that the reduction of interstitials in {311} defects at high phosphorus concentrations is due to the formation of phosphorus-interstitial clusters (PICs). The critical concentration for clustering (approximately 1.0 x 1019 cm-3 at 750°C) is strongly temperature dependent and in close agreement with the kink concentration of phosphorus diffusion. Information gained from these "well experiments" is applied to the study of direct phosphorus implantation. An experimental study is conducted on 40keV phosphorus implanted to a dose of 1.0 x 1014 cm-2 during 650-800°C anneals. Electrically inactive PICs are shown to form at concentrations below the solid solubility limit due to high interstitial supersaturations. Data useful for developing a model to accurately predict phosphorus diffusion under nonequilibrium conditions are extracted from the experimental results. A cluster-mediated diffusion model is developed using the