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Sample records for metallurgy enterprises bacillariophyta

  1. Plutonium Metallurgy

    SciTech Connect

    Freibert, Franz J.

    2012-08-09

    Due to its nuclear properties, Pu will remain a material of global interest well into the future. Processing, Structure, Properties and Performance remains a good framework for discussion of Pu materials science Self-irradiation and aging effects continue to be central in discussions of Pu metallurgy Pu in its elemental form is extremely unstable, but alloying helps to stabilize Pu; but, questions remain as to how and why this stabilization occurs. Which is true Pu-Ga binary phase diagram: US or Russian? Metallurgical issues such as solute coring, phase instability, crystallographic texture, etc. result in challenges to casting, processing, and properties modeling and experiments. For Ga alloyed FCC stabilized Pu, temperature and pressure remain as variables impacting phase stability.

  2. [Atmospheric emission of PCDD/Fs from secondary aluminum metallurgy industry in the southwest area, China].

    PubMed

    Lu, Yi; Zhang, Xiao-Ling; Guo, Zhi-Shun; Jian, Chuan; Zhu, Ming-Ji; Deng, Li; Sun, Jing; Zhang, Qin

    2014-01-01

    Five secondary aluminum metallurgy enterprises in the southwest area of China were measured for emissions of PCDD/Fs. The results indicated that the emission levels of PCDD/Fs (as TEQ) were 0.015-0.16 ng x m(-3), and the average was 0.093 ng x m(-3) from secondary aluminum metallurgy enterprises. Emission factors of PCDD/Fs (as TEQ) from the five secondary aluminum metallurgy enterprises varied between 0.041 and 4.68 microg x t(-1) aluminum, and the average was 2.01 microg x t(-1) aluminum; among them, PCDD/Fs emission factors from the crucible smelting furnace was the highest. Congener distribution of PCDD/F in stack gas from the five secondary aluminum metallurgies was very different from each other. Moreover, the R(PCDF/PCDD) was the lowest in the enterprise which was installed only with bag filters; the R(PCDF/PCDD) were 3.8-12.6 (the average, 7.7) in the others which were installed with water scrubbers. The results above indicated that the mechanism of PCDD/Fs formation was related to the types of exhaust gas treatment device. The results of this study can provide technical support for the formulation of PCDD/Fs emission standards and the best available techniques in the secondary aluminum metallurgy industry. PMID:24720181

  3. Metallurgy Beyond Iron

    NASA Astrophysics Data System (ADS)

    Gallino, Isabella; Busch, Ralf

    2009-08-01

    Metallurgy is one of the oldest sciences. Its history can be traced back to 6000 BCE with the discovery of Gold, and each new discovery - Copper, Silver, Lead, Tin, Iron and Mercury - marked the beginning of a new era of civilization. Currently there are 86 known metals, but until the end of the 17th century, only 12 of these were known. Steel (Fe-C alloy) was discovered in the 11th century BCE; however, it took until 1709 CE before we mastered the smelting of pig-iron by using coke instead of charcoal and started the industrial revolution. The metallurgy of nowadays is mainly about discovering better materials with superior properties to fulfil the increasing demand of the global market. Promising are the Glassy Metals or Bulk Metallic Glasses (BMGs) - discovered at first in the late 50s at the California Institute of Technology - which are several times stronger than the best industrial steels and 10-times springier. The unusual structure that lacks crystalline grains makes BMGs so promising. They have a liquid-like structure that means they melt at lower temperatures, can be moulded nearly as easily as plastics, and can be shaped into features just 10 nm across. The best BMG formers are based on Zr, Pd, Pt, Ca, Au and, recently discovered, also Fe. They have typically three to five components with large atomic size mismatch and a composition close to a deep eutectic. Packing in such liquids is very dense, with a low content of free volume, resulting in viscosities that are several orders of magnitude higher than in pure metal melts.

  4. Metallography of powder metallurgy materials

    SciTech Connect

    Lawley, Alan; Murphy, Thomas F

    2003-12-15

    The primary distinction between the microstructure of an ingot metallurgy/wrought material and one fabricated by the powder metallurgy route of pressing followed by sintering is the presence of porosity in the latter. In its various morphologies, porosity affects the mechanical, physical, chemical, electrical and thermal properties of the material. Thus, it is important to be able to characterize quantitatively the microstructure of powder metallurgy parts and components. Metallographic procedures necessary for the reliable characterization of microstructures in powder metallurgy materials are reviewed, with emphasis on the intrinsic challenges presented by the presence of porosity. To illustrate the utility of these techniques, five case studies are presented involving powder metallurgy materials. These case studies demonstrate problem solving via metallography in diverse situations: failure of a tungsten carbide-coated precipitation hardening stainless steel, failure of a steel pump gear, quantification of the degree of sinter (DOS), simulation of performance of a porous filter using automated image analysis, and analysis of failure in a sinter brazed part assembly.

  5. The extractive metallurgy of gold

    NASA Astrophysics Data System (ADS)

    Kongolo, K.; Mwema, M. D.

    1998-12-01

    Mössbauer spectroscopy has been successfully used in investigation of the gold compounds present in ores and the gold species which occur during the process metallurgy of this metal. This paper is a survey of the basic recovery methods and techniques used in extractive metallurgy of gold. Process fundamentals on mineral processing, ore leaching, zinc dust cementation, adsorption on activated carbon, electrowinning and refining are examined. The recovery of gold as a by-product of the copper industry is also described. Alternative processing methods are indicated in order to shed light on new interesting research topics where Mössbauer spectroscopy could be applied.

  6. Aluminum powder metallurgy processing

    NASA Astrophysics Data System (ADS)

    Flumerfelt, Joel Fredrick

    In recent years, the aluminum powder industry has expanded into non-aerospace applications. However, the alumina and aluminum hydroxide in the surface oxide film on aluminum powder require high cost powder processing routes. A driving force for this research is to broaden the knowledge base about aluminum powder metallurgy to provide ideas for fabricating low cost aluminum powder components. The objective of this dissertation is to explore the hypothesis that there is a strong linkage between gas atomization processing conditions, as-atomized aluminum powder characteristics, and the consolidation methodology required to make components from aluminum powder. The hypothesis was tested with pure aluminum powders produced by commercial air atomization commercial inert gas atomization and gas atomization reaction synthesis (GARS). The commercial atomization methods are bench marks of current aluminum powder technology. The GARS process is a laboratory scale inert gas atomization facility. A benefit of using pure aluminum powders is an unambiguous interpretation of the results without considering the effects of alloy elements. A comparison of the GARS aluminum powders with the commercial aluminum powders showed the former to exhibit superior powder characteristics. The powders were compared in terms of size and shape, bulk chemistry, surface oxide chemistry and structure, and oxide film thickness. Minimum explosive concentration measurements assessed the dependence of explosibility hazard on surface area, oxide film thickness, and gas atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization oxidation of aluminum powder. An Al-Ti-Y GARS alloy exposed in ambient air at different temperatures revealed the effect of reactive alloy elements on post-atomization powder oxidation. The pure aluminum powders were consolidated by two different routes, a

  7. Recent trends in extractive metallurgy

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    Metallurgists and solution geochemists are joining forces to develop processes for extraction of metals from low-grade ores. The processes, which come under the name hydrometallurgy, include several new applications of solvent extraction techniques. Aqueous solutions are employed, leaching metals from ores, mine waste dumps, and even from deposits still in the ground. It was notable, for example, that Chemical and Engineering News (Feb. 8, 1982) recently featured the subject of hydrometallurgy in a special report. They noted that ‘recovering metals by use of aqueous solutions at relatively low temperatures increasingly is competing with dry, high-temperature pyrometallurgical methods.’ The relatively new techniques have caused a revolution, of sorts, in engineering programs of university metallurgy departments. The challenge of developing selective metal dissolution processes is drawing upon the best national talent in the fields of solution geochemistry and metallurgy.

  8. Silicon solar cells: Physical metallurgy principles

    NASA Astrophysics Data System (ADS)

    Mauk, Michael G.

    2003-05-01

    This article reviews the physical metallurgy aspects of silicon solar cells. The production of silicon solar cells relies on principles of thermochemical extractive metallurgy, phase equilibria, solidification, and kinetics. The issues related to these processes and their impact on solar cell performance and cost are discussed.

  9. The Rules of Ferrous Metallurgy

    PubMed Central

    2010-01-01

    The ways in which the sciences have been delineated and categorized throughout history provide insights into the formation, stabilization, and establishment of scientific systems of knowledge. The Dresdener school’s approach for explaining and categorizing the genesis of the engineering disciplines is still valid, but needs to be complemented by further-reaching methodological and theoretical reflections. Pierre Bourdieu’s theory of social practice is applied to the question of how individual agents succeed in influencing decisively a discipline’s changing object orientation, institutionalisation and self-reproduction. Through the accumulation of social, cultural and economic capital, they succeed in realising their own organisational ideas and scientific programs. Key concepts for the analysis include the struggle for power and resources, monopolies of interpretation, and the degree of autonomy. A case study from the Aachener Technische Hochschule shows that the consolidation of ferrous metallurgy can be conceived as a symbolical struggle between Fritz Wüst, professor for ferrous metallurgy, and the German Iron and Steel Institute, leading to a construction of a system of differences in which scientists accepted being scientists rather than entrepreneurs, and entrepreneurs accepted becoming entrepreneurs and renounced science.

  10. Advanced powder metallurgy aluminum alloys and composites

    NASA Technical Reports Server (NTRS)

    Lisagor, W. B.; Stein, B. A.

    1982-01-01

    The differences between powder and ingot metallurgy processing of aluminum alloys are outlined. The potential payoff in the use of advanced powder metallurgy (PM) aluminum alloys in future transport aircraft is indicated. The national program to bring this technology to commercial fruition and the NASA Langley Research Center role in this program are briefly outlined. Some initial results of research in 2000-series PM alloys and composites that highlight the property improvements possible are given.

  11. Powder-Metallurgy Process And Product

    NASA Technical Reports Server (NTRS)

    Paris, Henry G.

    1988-01-01

    Rapid-solidification processing yields alloys with improved properties. Study undertaken to extend favorable property combinations of I/M 2XXX alloys through recently developed technique of rapid-solidification processing using powder metallurgy(P/M). Rapid-solidification processing involves impingement of molten metal stream onto rapidly-spinning chill block or through gas medium using gas atomization technique.

  12. Powder metallurgy bearings for advanced rocket engines

    NASA Technical Reports Server (NTRS)

    Fleck, J. N.; Killman, B. J.; Munson, H.E.

    1985-01-01

    Traditional ingot metallurgy was pushed to the limit for many demanding applications including antifriction bearings. New systems require corrosion resistance, better fatigue resistance, and higher toughness. With conventional processing, increasing the alloying level to achieve corrosion resistance results in a decrease in other properties such as toughness. Advanced powder metallurgy affords a viable solution to this problem. During powder manufacture, the individual particle solidifies very rapidly; as a consequence, the primary carbides are very small and uniformly distributed. When properly consolidated, this uniform structure is preserved while generating a fully dense product. Element tests including rolling contact fatigue, hot hardness, wear, fracture toughness, and corrosion resistance are underway on eleven candidate P/M bearing alloys and results are compared with those for wrought 440C steel, the current SSME bearing material. Several materials which offer the promise of a significant improvement in performance were identified.

  13. The EDM surface: Topography, chemistry, and metallurgy

    SciTech Connect

    Fuller, J.E.

    1991-01-01

    The surface created by the electric discharge machining (EDM) process is of special interest because it has been shown to have a negative effect on the fatigue properties of many alloys. An understanding of the surface metallurgy and chemistry is important in predicting those alloys which are most susceptible to failure. Remedial actions, including thickness minimization, alteration, or removal of the surface layer are addressed.

  14. Physical Metallurgy of High-Entropy Alloys

    NASA Astrophysics Data System (ADS)

    Yeh, Jien-Wei

    2015-08-01

    Two definitions of high-entropy alloys (HEAs), based on composition and entropy, are reviewed. Four core effects, i.e., high entropy, sluggish diffusion, severe lattice distortion, and cocktail effects, are mentioned to show the uniqueness of HEAs. The current state of physical metallurgy is discussed. As the compositions of HEAs are entirely different from that of conventional alloys, physical metallurgy principles might need to be modified for HEAs. The thermodynamics, kinetics, structure, and properties of HEAs are briefly discussed relating with the four core effects of HEAs. Among these, a severe lattice distortion effect is particularly emphasized because it exerts direct and indirect influences on many aspects of microstructure and properties. Because a constituent phase in HEAs can be regarded as a whole-solute matrix, every lattice site in the matrix has atomic-scale lattice distortion. In such a distorted lattice, point defects, line defects, and planar defects are different from those in conventional matrices in terms of atomic configuration, defect energy, and dynamic behavior. As a result, mechanical and physical properties are significantly influenced by such a distortion. Suitable mechanisms and theories correlating composition, microstructure, and properties for HEAs are required to be built in the future. Only these understandings make it possible to complete the physical metallurgy of the alloy world.

  15. Low-Cobalt Powder-Metallurgy Superalloy

    NASA Technical Reports Server (NTRS)

    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).

  16. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-19

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  17. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goval, Amit; Williams, Robert K.; Kroeger, Donald M.

    2005-06-07

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  18. Biaxially textured articles formed by power metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-26

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  19. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-07-29

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  20. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2004-09-14

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  1. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-05

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of ternary mixtures consisting of: Ni powder, Cu powder, and Al powder, Ni powder, Cr powder, and Al powder; Ni powder, W powder and Al powder; Ni powder, V powder, and Al powder; Ni powder, Mo powder, and Al powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  2. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2005-05-10

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  3. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-26

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  4. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2004-09-28

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  5. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2005-01-25

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  6. Densification of powder metallurgy billets by a roll consolidation technique

    NASA Technical Reports Server (NTRS)

    Sellman, W. H.; Weinberger, W. R.

    1973-01-01

    Container design is used to convert partially densified powder metallurgy compacts into fully densified slabs in one processing step. Technique improves product yield, lowers costs and yields great flexibility in process scale-up. Technique is applicable to all types of fabricable metallic materials that are produced from powder metallurgy process.

  7. Metallurgy and Heat Treating. Welding Module 7. Instructor's Guide.

    ERIC Educational Resources Information Center

    Missouri Univ., Columbia. Instructional Materials Lab.

    This guide is intended to assist vocational educators in teaching a three-unit module in metallurgy and heat treating. The module is part of a welding curriculum that has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The basic principles of metallurgy and heat treatment and techniques for…

  8. Enterprise Trends

    ERIC Educational Resources Information Center

    Technology & Learning, 2007

    2007-01-01

    Education research experts Eduventures released a report in February 2007 on where U.S. districts are headed with large system management. "Trends in K-12 Enterprise Management: Are Districts Ready to Cross the Chasm?" provides a detailed assessment of the themes and the trends that are driving the market for K-12 enterprise management systems.…

  9. Influence of water pollution on the growth and pigment concentration of the microalgae Phaeodactylum tricornutum Bohlin (Bacillariophyta).

    PubMed

    Zhuravel, Elena V; Markina, Zhanna V; Aizdaicher, Nina A

    2012-05-01

    The aim of the work was to study the influence of the water taken from one of the most polluted parts of the Peter the Great Bay (the Japan Sea), the Nakhodka Bay, on the growth and chlorophyll a concentration in the cells of microalga P. tricornutum Bohlin (Bacillariophyta). The estimation of the dynamics of cell number growth and chlorophyll a concentration in the cells of microalga grown in the water from the Nakhodka Bay was made. At the same time, in 2007-2008, the main hydrochemical parameters, such as water salinity, dissolved oxygen concentration, BOD(5), organic and mineral phosphates concentration, anionic surfactants, and total petroleum hydrocarbons, were determined. It is shown that in July 2007, when most hydrochemical parameters were lower than the maximum permissible level, the culture growth and chlorophyll a contents in the cells did not differ from the control for certain. In other seasons these indices differed greatly from the control. The positive correlation between the concentration of dissolved oxygen, phosphates, petroleum hydrocarbons, and the number of microalga cells, grown in the water from the Nakhodka Bay, was shown. PMID:21713489

  10. Evaluation of powder metallurgy superalloy disk materials

    NASA Technical Reports Server (NTRS)

    Evans, D. J.

    1975-01-01

    A program was conducted to develop nickel-base superalloy disk material using prealloyed powder metallurgy techniques. The program included fabrication of test specimens and subscale turbine disks from four different prealloyed powders (NASA-TRW-VIA, AF2-1DA, Mar-M-432 and MERL 80). Based on evaluation of these specimens and disks, two alloys (AF2-1DA and Mar-M-432) were selected for scale-up evaluation. Using fabricating experience gained in the subscale turbine disk effort, test specimens and full scale turbine disks were formed from the selected alloys. These specimens and disks were then subjected to a rigorous test program to evaluate their physical properties and determine their suitability for use in advanced performance turbine engines. A major objective of the program was to develop processes which would yield alloy properties that would be repeatable in producing jet engine disks from the same powder metallurgy alloys. The feasibility of manufacturing full scale gas turbine engine disks by thermomechanical processing of pre-alloyed metal powders was demonstrated. AF2-1DA was shown to possess tensile and creep-rupture properties in excess of those of Astroloy, one of the highest temperature capability disk alloys now in production. It was determined that metallographic evaluation after post-HIP elevated temperature exposure should be used to verify the effectiveness of consolidation of hot isostatically pressed billets.

  11. Ancient metallurgy and nuclear waste containment

    SciTech Connect

    Goodway, M.

    1993-12-31

    Archaeological artifacts of glass, ceramic, and metal provide examples of long term durability and as such have been surveyed by the nuclear agencies of several countries as a possible guide to choices of materials for the containment of nuclear waste. In the case of metals evaluation is difficult because of the loss of many artifacts to recycling and corrosion processes, as well as by uncertainty as to the environmental history under which the remainder survived. More recently the study of ancient metallurgy has expanded to included other materials associated with metals processing. It is suggested that an impermeable ceramic composite used in ancient metals processing installations should be reproduced and tested for its resistance to radiation damage. This material was synthesized more than two millennia ago and has a proven record of durability. These installations have had no maintenance but are intact, some still holding water.

  12. Electrodeposition in extractive metallurgy: An emerging technology?

    NASA Astrophysics Data System (ADS)

    O'Keefe, Thomas J.

    1992-04-01

    The electrowinning and electrorefining of metals from aqueous solutions continues to be one of the essential unit processes employed in nonferrous extractive metallurgy. Current processes effectively address both ohmic and mass transport of the primary metal ion in their design. Some deficiencies exist, however, in the basic understanding of the other two critical elements essential in cathodic deposition: activation kinetics and electrocrystallization. The understanding of the latter two must be elevated to the level of understanding of ohmic and mass transport if truly new and innovative advances are to occur. Because of the increasingly demanding standards for electrometallurgy processes and products, technical progress must be made if a competitive edge is to be maintained in the future.

  13. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-10-21

    A strengthened, biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed, compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: Ni, Ag, Ag--Cu, Ag--Pd, Ni--Cu, Ni--V, Ni--Mo, Ni--Al, Ni--Cr--Al, Ni--W--Al, Ni--V--Al, Ni--Mo--Al, Ni--Cu--Al; and at least one fine metal oxide powder; the article having a grain size which is fine and homogeneous; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  14. Looking North into Lab Metallurgy Testing Area and Enrichment Motor ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking North into Lab Metallurgy Testing Area and Enrichment Motor within Recycle Recovery Building - Hematite Fuel Fabrication Facility, Recycle Recovery Building, 3300 State Road P, Festus, Jefferson County, MO

  15. 1. Photocopy from J. L. Bray, The Principles of Metallurgy, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Photocopy from J. L. Bray, The Principles of Metallurgy, Ginn & Company, New York, 1929 - International Smelting & Refining Company, Tooele Smelter, Sinter Plant, State Route 178, Tooele, Tooele County, UT

  16. Powder metallurgy process for manufacturing core projectile

    NASA Astrophysics Data System (ADS)

    Akbar, Taufik; Setyowati, Vuri Ayu; Widyastuti

    2013-09-01

    Bullets are part of the defense equipment which the development is very rapid. There are a variety of forms but the bullet Lead is a metal that has always been used for applications projectiles. Lead core constituent materials are combined with antimony. In this research will be conducted by making the material for the core projectile with Tin Lead. The addition of Tin will increase the stiffness of Lead which is soft in nature. The Lead Tin composition variation was given in 10% weight of Sn. The manufacturing process using powder metallurgy using temperature and holding time variations of sintering at 100, 150, and 200°C for 1,2, and 3 hours. XRD samples will be tested to determine the form and phase morphology was observed using SEM-EDX. These results revealed that Pb-10%wtSn Composite which is sintered in temperature 200°C for 3 hours has the greatest density, 10.695 g/cm3 as well as the smallest porosity, 2.2%. In agreement with theoretical analysis that increasing higher temperature and longer holding time give decrease in porosity level due to activation energy which further promotes grain growth. Moreover, there is no intermetallic phase formation as well as no oxide found on composites.

  17. Electrothermal Defect Detection in Powder Metallurgy Compacts

    NASA Astrophysics Data System (ADS)

    Benzerrouk, Souheil; Ludwig, Reinhold; Apelian, Diran

    2006-03-01

    Faced with increasing market pressures, metal part manufacturers have turned to new processes and fabrication technologies. One of these processes is powder metallurgy (P/M), which is employed for low-cost, high-volume precision part manufacturing. Despite many advantages, the P/M process has created a number of challenges, including the need for high-speed quality assessment and control, ideally for each compact. Consequently, sophisticated quality assurance is needed to rapidly detect flaws early in the manufacturing cycle and at minimal cost. In this paper we will discuss our progress made in designing and refining an active infrared (IR) detection system for P/M compacts. After discussing the theoretical background in terms of underlying equations and boundary conditions, analytical and numerical solutions are presented that are capable of predicting temperature responses for various defect sizes and orientations of a dynamic IR testing system. Preliminary measurements with controlled and industrial samples have shown that this active IR methodology can successfully be employed to test both green-state and sintered P/M compacts. The developed system can overcome many limitations observed with a standard IR testing methodology such as emissivity, background calibration, and contact resistance.

  18. Ti Multicomponent Alloy Bulks by Powder Metallurgy

    NASA Astrophysics Data System (ADS)

    Zhang, Kuibao; Wen, Guanjun; Dai, Hongchuan; Teng, Yuancheng; Li, Yuxiang

    2014-10-01

    In this study, CrCuFeMnMo0.5Ti multicomponent alloy bulks were prepared by powder metallurgy of mechanical alloying and sintering. A simple body-centered cubic (bcc) solid solution was prepared after 40 h ball milling of the raw CrCuFeMnMo0.5Ti metallic powder. Particles of the alloyed powder are in microsized structures, which are actually a soft agglomeration of lamellar grains with thicknesses less than 1 μm. Meanwhile, the lamellar granules are consisted of nanosized grains under rigid cold welding. The 80-h ball-milled powder was consolidated by cold pressing and subsequent sintering at 800°C. The observed main phase in the consolidated sample after milling for 80 h is still a bcc solid solution. The solidified sample of 80-h ball-milled powder exhibits a Vickers hardness of 468 HV, which is much higher than 171 HV of the counterpart prepared from the raw metallic powder.

  19. A major advance in powder metallurgy

    NASA Technical Reports Server (NTRS)

    Williams, Brian E.; Stiglich, Jacob J., Jr.; Kaplan, Richard B.; Tuffias, Robert H.

    1991-01-01

    Ultramet has developed a process which promises to significantly increase the mechanical properties of powder metallurgy (PM) parts. Current PM technology uses mixed powders of various constituents prior to compaction. The homogeneity and flaw distribution in PM parts depends on the uniformity of mixing and the maintenance of uniformity during compaction. Conventional PM fabrication processes typically result in non-uniform distribution of the matrix, flaw generation due to particle-particle contact when one of the constituents is a brittle material, and grain growth caused by high temperature, long duration compaction processes. Additionally, a significant amount of matrix material is usually necessary to fill voids and create 100 percent dense parts. In Ultramet's process, each individual particle is coated with the matrix material, and compaction is performed by solid state processing. In this program, Ultramet coated 12-micron tungsten particles with approximately 5 wt percent nickel/iron. After compaction, flexure strengths were measured 50 percent higher than those achieved in conventional liquid phase sintered parts (10 wt percent Ni/Fe). Further results and other material combinations are discussed.

  20. Pressurized metallurgy for high performance special steels and alloys

    NASA Astrophysics Data System (ADS)

    Jiang, Z. H.; Zhu, H. C.; Li, H. B.; L1, Y.; Liu, F. B.

    2016-07-01

    The pressure is one of the basic parameters which greatly influences the metallurgical reaction process and solidification of steels and alloys. In this paper the history and present situation of research and application of pressurized metallurgy, especially pressurized metallurgy for special steels and alloys have been briefly reviewed. In the following part the physical chemistry of pressurized metallurgy is summarized. It is shown that pressurizing may change the conditions of chemical reaction in thermodynamics and kinetics due to the pressure effect on gas volume, solubility of gas and volatile element in metal melt, activity or activity coefficient of components, and change the physical and chemical properties of metal melt, heat transfer coefficient between mould and ingot, thus greatly influencing phase transformation during the solidification process and the solidification structure, such as increasing the solidification nucleation rate, reducing the critical nucleation radius, accelerating the solidification speed and significant macro/micro-structure refinement, and eliminating shrinkage, porosity and segregation and other casting defects. In the third part the research works of pressured metallurgy performed by the Northeastern University including establishment of pressurized induction melting (PIM) and pressurized electroslag remelting (PESR) equipments and development of high nitrogen steels under pressure are described in detail. Finally, it is considered in the paper that application of pressurized metallurgy in manufacture of high performance special steels and alloys is a relatively new research area, and its application prospects will be very broad and bright.

  1. Metallurgy and properties of plasma spray formed materials

    NASA Technical Reports Server (NTRS)

    Mckechnie, T. N.; Liaw, Y. K.; Zimmerman, F. R.; Poorman, R. M.

    1992-01-01

    Understanding the fundamental metallurgy of vacuum plasma spray formed materials is the key to enhancing and developing full material properties. Investigations have shown that the microstructure of plasma sprayed materials must evolve from a powder splat morphology to a recrystallized grain structure to assure high strength and ductility. A fully, or near fully, dense material that exhibits a powder splat morphology will perform as a brittle material compared to a recrystallized grain structure for the same amount of porosity. Metallurgy and material properties of nickel, iron, and copper base alloys will be presented and correlated to microstructure.

  2. Why materials science and engineering is good for metallurgy

    NASA Astrophysics Data System (ADS)

    Flemings, Merton C.

    2001-04-01

    Metallurgy/materials education will continue to evolve to encompass, in an intellectually unified way, the full range of structural and functional materials. Computation, information, and other advanced sciences and technologies will assume increasing roles in materials education, as will distance and continuing education. The advantages of the changes will be many … to the graduates, to emerging industries, and to the traditional metallurgical industries seeking productive, creative young engineers as employees. The need for continuing change in our metallurgy/materials departments is now no less if we are to attract the best young people into our field in the numbers needed and to best serve the needs of industry.

  3. Why materials science and engineering is good for metallurgy

    NASA Astrophysics Data System (ADS)

    Flemings, Merton C.

    2001-04-01

    Metallurgy/materials education will continue to evolve to encompass, in an intellectually unified way, the full range of structural and functional materials. Computation, information, and other advanced sciences and technologies will assume increasing roles in materials education, as will distance and continuing education. The advantages of the changes will be many ... to the graduates, to emerging industries, and to the traditional metallurgical industries seeking productive, creative young engineers as employees. The need for continuing change in our metallurgy/materials departments is now no less if we are to attract the best young people into our field in the numbers and to best serve the needs of industry.

  4. Chemical and Metallurgy Research (CMR) Sample Tracking System Design Document

    SciTech Connect

    Bargelski, C. J.; Berrett, D. E.

    1998-09-01

    The purpose of this document is to describe the system architecture of the Chemical and Metallurgy Research (CMR) Sample Tracking System at Los Alamos National Laboratory. During the course of the document observations are made concerning the objectives, constraints and limitations, technical approaches, and the technical deliverables.

  5. Powder metallurgy of vanadium and its alloys (review)

    SciTech Connect

    Radomysel'skii, I.D.; Solntsev, V.P.; Evtushenko, O.V.

    1987-10-01

    This article reviews the current powder metallurgy technology of vanadium and its alloys. Data are given on sintering, compacting, electrowinning and other current production techniques, as well as on the corrosion behavior and mechanical and physical properties of alloys produced by these different methods. The use of vanadium alloys as reactor and jet engine materials is also briefly discussed.

  6. One step HIP canning of powder metallurgy composites

    NASA Technical Reports Server (NTRS)

    Juhas, John J. (Inventor)

    1990-01-01

    A single step is relied on in the canning process for hot isostatic pressing (HIP) powder metallurgy composites. The binders are totally removed while the HIP can of compatible refractory metal is sealed at high vacuum and temperature. This eliminates outgassing during hot isostatic pressing.

  7. 39. GENERAL VIEW LOOKING NORTH, SHOWING BUILDING NO. 318, METALLURGY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    39. GENERAL VIEW LOOKING NORTH, SHOWING BUILDING NO. 318, METALLURGY LAB, ON RIGHT, BUILDING NO. 319, GENERAL PURPOSE ADMINISTRATION BUILDING, ON LEFT AND BUILDING NO. 355, ADMINISTRATION BUILDING, RESEARCH & DEVELOPMENT, IN BACKGROUND LEFT. - Picatinny Arsenal, State Route 15 near I-80, Dover, Morris County, NJ

  8. Iron Metallurgy: Technical Terminology Bulletin. Terminotech, Vol. 2, No. 7.

    ERIC Educational Resources Information Center

    General Electric Co. of Canada, Ltd., Montreal, Quebec.

    This issue of a bulletin of technological terminology is devoted to iron metallurgy. Various aspects of iron production are described in both French and English. An English-French dictionary of terms comprises the bulk of the document. Explanatory illustrations are appended. (JB)

  9. NSF: A "Populist" Pattern in Metallurgy, Materials Research?

    ERIC Educational Resources Information Center

    Shapley, Deborah

    1975-01-01

    Describes the testimony of a University of Virginia professor of applied science, who charged that the National Science Foundation grants disproportionately small funds to the best university departments in the field of metallurgy and materials, while preferentially funding middle-ranked departments. (MLH)

  10. Is Enterprise Education Relevant to Social Enterprise?

    ERIC Educational Resources Information Center

    Bridge, Simon

    2015-01-01

    Purpose: Both enterprise education and social enterprise have become fashionable but what, if any, should be the connections between them? The purpose of this paper is to explore those connections and to reflect on what relevance the two concepts might have for each other. Design/methodology/approach: Both enterprise education and social…

  11. Enterprise analytics.

    SciTech Connect

    Spomer, Judith E.

    2010-09-01

    Ranking search results is a thorny issue for enterprise search. Search engines rank results using a variety of sophisticated algorithms, but users still complain that search can't ever seem to find anything useful or relevant! The challenge is to provide results that are ranked according to the users definition of relevancy. Sandia National Laboratories has enhanced its commercial search engine to discover user preferences, re-ranking results accordingly. Immediate positive impact was achieved by modeling historical data consisting of user queries and subsequent result clicks. New data is incorporated into the model daily. An important benefit is that results improve naturally and automatically over time as a function of user actions. This session presents the method employed, how it was integrated with the search engine,metrics illustrating the subsequent improvement to the users search experience, and plans for implementation with Sandia's FAST for SharePoint 2010 search engine.

  12. Milling and Drilling Evaluation of Stainless Steel Powder Metallurgy Alloys

    SciTech Connect

    Lazarus, L.J.

    2001-12-10

    Near-net-shape components can be made with powder metallurgy (PM) processes. Only secondary operations such as milling and drilling are required to complete these components. In the past and currently production components are made from powder metallurgy (PM) stainless steel alloys. process engineers are unfamiliar with the difference in machining properties of wrought versus PM alloys and have had to make parts to develop the machining parameters. Design engineers are not generally aware that some PM alloy variations can be furnished with machining additives that greatly increase tool life. Specimens from a MANTEC PM alloy property study were made available. This study was undertaken to determine the machining properties of a number of stainless steel wrought and PM alloys under the same conditions so that comparisons of their machining properties could be made and relative tool life determined.

  13. Powder Metallurgy Fabrication of Molybdenum Accelerator Target Disks

    SciTech Connect

    Lowden, Richard Andrew; Kiggans Jr., James O.; Nunn, Stephen D.; Parten, Randy J.

    2015-12-01

    Powder metallurgy approaches for the fabrication of accelerator target disks are being examined to support the development of Mo-99 production by NorthStar Medical Technologies, LLC. An advantage of powder metallurgy is that very little material is wasted and at present, dense, quality parts are routinely produced from molybdenum powder. The proposed targets, however, are thin wafers, 29 mm in diameter with a thickness of 0.5 mm, with very stringent dimensional tolerances. Although tooling can be machined to very high tolerance levels, the operations of powder feed, pressing and sintering involve complicated mechanisms, each of which affects green density and shrinkage, and therefore the dimensions and shape of the final product. Combinations of powder morphology, lubricants and pressing technique have been explored to produce target disks with minimal variations in thickness and little or no distortion. In addition, sintering conditions that produce densities for optimum target dissolvability are being determined.

  14. Near-Net Shape Powder Metallurgy Rhenium Thruster

    NASA Technical Reports Server (NTRS)

    Leonhardt, Todd; Hamister, Mark; Carlen, Jan C.; Biaglow, James; Reed, Brian

    2001-01-01

    This paper describes the development of a method to produce a near-net shape (NNS) powder metallurgy (PM) rhenium combustion chamber of the size 445 N (100 lbf) used in a high performance liquid apogee engine. These engines are used in low earth Orbit and geostationary orbit for satellite positioning systems. The developments in near-net shape powder metallurgy rhenium combustion chambers reported in this paper will reduce manufacturing cost of the rhenium chambers by 25 percent, and reduce the manufacturing time by 30 to 40 percent. The quantity of rhenium metal powder used to produce a rhenium chamber is reduced by approximately 70 percent and the subsequent reduction in machining schedule and costs is nearly 50 percent.

  15. Modulus Dependence on Large Scale Porosity of Powder Metallurgy Steel

    NASA Astrophysics Data System (ADS)

    Allison, P. G.; Horstemeyer, M. F.; Brown, H. R.

    2012-07-01

    This article compares the existing theoretical expressions for the porosity dependence on elastic constants to experimental data for a commercially available material, FC-0205 powder metallurgy (PM) steel. The modulus of compression, tension, effective torsion, and ultrasound-based data at varying porosity levels are plotted graphically against the theoretical expressions. An equation by McAdam ( J. Iron Steel Inst. Lond., 1950, 168, p 346) was able to most accurately predict the experimental data with the adjustment of only one material constant.

  16. Microstructure and Aging of Powder-Metallurgy Al Alloys

    NASA Technical Reports Server (NTRS)

    Blackburn, L. B.

    1987-01-01

    Report describes experimental study of thermal responses and aging behaviors of three new aluminum alloys. Alloys produced from rapidly solidified powders and contain 3.20 to 5.15 percent copper, 0.24 to 1.73 percent magnesium, 0.08 to 0.92 percent iron, and smaller amounts of manganese, nickel, titanium, silicon, and zinc. Peak hardness achieved at lower aging temperatures than with standard ingot-metallurgy alloys. Alloys of interest for automobile, aircraft, and aerospace applications.

  17. Powder-metallurgy superalloy strengthened by a secondary gamma phase.

    NASA Technical Reports Server (NTRS)

    Kotval, P. S.

    1971-01-01

    Description of experiments in which prealloyed powders of superalloy compositions were consolidated by extrusion after the strengthening by precipitation of a body-centered tetragonal gamma secondary Ni3 Ta phase. Thin foil electron microscopy showed that the mechanical properties of the resultant powder-metallurgy product were correlated with its microstructure. The product exhibited high strength at 1200 F without loss of ductility, after thermomechanical treatment and aging.

  18. Enterprise identity management strategies.

    PubMed

    Hewitt, Joseph B; Schumacher, Scott; Weber, Gerald I

    2002-01-01

    The need for an enterprise-wide person-centric approach to patient identification is presented, along with the challenges to achieving that objective and guidelines to the actions and technology that will support the enterprise view. PMID:12119845

  19. Improving Enterprise in Education

    ERIC Educational Resources Information Center

    Her Majesty's Inspectorate of Education, 2008

    2008-01-01

    "Improving Enterprise in Education" evaluates enterprise in education using a framework developed in direct response to a recommendation in "Determined to Succeed." The framework comprised quality indicators, chosen from the second edition of "How good is our school?" to focus on key features of enterprise in education: learners' experiences,…

  20. Welding Metallurgy and Processing Issues for Joining of Power Sources

    SciTech Connect

    Lienert, Thomas J.; Reardon, Patrick T.

    2012-08-14

    Weldability issues with the pertinent alloys have been reviewed and preliminary results of our work on Haynes 25 have been presented. Further results on the mechanical properties and metallography on the EB welds are imminent. Hot-ductility experiments will commence within a few weeks. Aging studies on the effects of heat treatment using the Gleeble are also planned. MST-6 has extensive background in the welding metallurgy of the pertinent alloys. We also have considerable experience with the various welding processes to be used.

  1. Chloride metallurgy: PGM recovery and titanium dioxide production

    NASA Astrophysics Data System (ADS)

    Puvvada, G. V. K.; Sridhar, R.; Lakshmanan, V. I.

    2003-08-01

    This paper examines in detail the thermodynamics and application of chloride metallurgy for the extraction of precious metals, such as gold and silver, and platinum-group metals. The advantages with regard to the solubilities of metal ion species and their reduction potentials in chloride media are discussed with examples. The use of chloride media for the extraction of platinum-group metals from spent autocatalysts and for the production of high-purity pigment-grade TiO2 and titanium metal from ilmenite feed stocks is discussed in the case studies provided.

  2. 78 FR 8202 - Meeting of the Joint ACRS Subcommittees on Thermal Hydraulic Phenomena and Materials, Metallurgy...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-05

    ... ACRS meetings were published in the Federal Register on October 18, 2012, (77 FR 64146- 64147... Hydraulic Phenomena and Materials, Metallurgy and Reactor Fuels; Notice of Meeting The Joint ACRS Subcommittees on Thermal Hydraulic Phenomena and Materials, Metallurgy and Reactor Fuels will hold a meeting...

  3. A New Space Enterprise

    NASA Video Gallery

    Doug Cooke, Associate Administrator for the Office of Exploration Systems Mission Directorate, welcomes participants and introduces NASA's Exploration Enterprise Workshop, held from May 25-26 2010 ...

  4. Ceramic Inclusions in Powder Metallurgy Disk Alloys: Characterization and Modeling

    NASA Technical Reports Server (NTRS)

    Bonacuse, Peter J.

    2001-01-01

    Powder metallurgy alloys are increasingly used in gas turbine engines, especially in turbine disk applications. Although powder metallurgy materials have many advantages over conventionally cast and wrought alloys (higher strength, higher temperature capability, etc.), they suffer from the rare occurrence of ceramic defects (inclusions) that are inherent to the powder atomization process. These inclusions can have a potentially large detrimental effect on the durability of individual components. An inclusion in a high stress location can act as a site for premature crack initiation and thereby considerably reduce the fatigue life. Because these inclusions are exceedingly rare, they typically do not reveal themselves in the process of characterizing the material for a particular application (the cumulative volume of the test bars in a fatigue life characterization is typically on the order of a single actual component). Ceramic inclusions have, however, been found to be the root cause of a number of catastrophic engine failures. To investigate the effect of these inclusions in detail, we have undertaken a study where known populations of ceramic particles, whose composition and morphology are designed to mimic the "natural" inclusions, are added to the precursor powder. Surface-connected inclusions have been found to have a particularly large detrimental effect on fatigue life; therefore, the quantity of ceramic "seeds" added is calculated to ensure that a minimum number will intersect the surface of the fatigue test bars. Because the ceramic inclusions are irregularly shaped and have a tendency to break up in the process of extrusion and forging, a method of calculating the probability of occurrence and expected intercepted surface area was needed. We have developed a Monte Carlo simulation to determine the distributions of these parameters and have verified the simulated results with observations of ceramic inclusions found in macroscopic slices from extrusions

  5. Powder metallurgy titanium 6A1-4V plate

    SciTech Connect

    Geisendorfer, R.F.

    1980-01-01

    A powder metallurgical approach has been combined with controlled mill processing to produce a highly uniform plate material suitable for structural applications. Prealloyed ELI Titanium 6A1-4V powder produced by the rotating electrode process was consolidated into billet by hot isostatic pressing. The resulting billet of uniform composition and random texture was then hot cross-rolled to 3 cm thick plate. Following rolling, the plate was given a beta annealing heat treatment to maximize damage tolerance. The plate was characterized with respect to metallurgical structure, composition, texture, and room temperature mechanical properties. The results of the study show that a powder metallurgy titanium mill product possessing uniform macro- and microstructure is technically feasible and exhibits tensile and fatigue properties equivalent to those of conventionally produced ingot-source wrought plate.

  6. The metallurgy and processing science of metal additive manufacturing

    DOE PAGESBeta

    Sames, William J.; List, III, Frederick Alyious; Pannala, Sreekanth; Dehoff, Ryan R.; Babu, Sudarsanam Suresh

    2016-03-07

    Here, additive Manufacturing (AM), widely known as 3D printing, is a method of manufacturing that forms parts from powder, wire, or sheets in a process that proceeds layer-by-layer.Many techniques (using many different names) have been developed to accomplish this via melting or solid - state joining. In this review, these techniques for producing metal parts are explored, with a focus on the science of metal AM: processing defects, heat transfer, solidification, solid- state precipitation, mechanical properties, and post-processing metallurgy. The various metal AM techniques are compared, with analysis of the strengths and limitations of each. Few alloys have been developedmore » for commercial production, but recent development efforts are presented as a path for the ongoing development of new materials for AM processes.« less

  7. Physical and mechanical metallurgy of high purity Nb accelerator cavities.

    SciTech Connect

    Wright, N. T.; Bieler, T. R.; Pourgoghart , F.; Compton, C.; Hartwig, K. T.; Baars, D.; Zamiri, A.; Chandrasekaran, S.; Darbandi, P.; Jiang, H.; Skoug, E.; Balachandran, S.; Ice, G. E.; Liu, W.; Michigan State Univ.; Texas A & M Univ.; ORNL

    2010-01-01

    In the past decade, high Q values have been achieved in high purity Nb superconducting radio frequency (SRF) cavities. Fundamental understanding of the physical metallurgy of Nb that enables these achievements is beginning to reveal what challenges remain to establish reproducible and cost-effective production of high performance SRF cavities. Recent studies of dislocation substructure development and effects of recrystallization arising from welding and heat treatments and their correlations with cavity performance are considered. With better fundamental understanding of the effects of dislocation substructure evolution and recrystallization on electron and phonon conduction, as well as the interior and surface states, it will be possible to design optimal processing paths for cost-effective performance using approaches such as hydroforming, which minimizes or eliminates welds in a cavity.

  8. The metallurgy and processing science of metal additive manufacturing

    SciTech Connect

    Sames, William J.; List, III, Frederick Alyious; Pannala, Sreekanth; Dehoff, Ryan R.; Babu, Sudarsanam Suresh

    2016-01-01

    Here, additive Manufacturing (AM), widely known as 3D printing, is a method of manufacturing that forms parts from powder, wire, or sheets in a process that proceeds layer-by-layer.Many techniques (using many different names) have been developed to accomplish this via melting or solid - state joining. In this review, these techniques for producing metal parts are explored, with a focus on the science of metal AM: processing defects, heat transfer, solidification, solid- state precipitation, mechanical properties, and post-processing metallurgy. The various metal AM techniques are compared, with analysis of the strengths and limitations of each. Few alloys have been developed for commercial production, but recent development efforts are presented as a path for the ongoing development of new materials for AM processes.

  9. N18, powder metallurgy superalloy for disks: Development and applications

    SciTech Connect

    Guedou, J.Y.; Lautridou, J.C.; Honnorat, Y. . 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.

  10. N18, Powder metallurgy superalloy for disks: Development and applications

    NASA Astrophysics Data System (ADS)

    Guedou, J. Y.; Lautridou, J. C.; Honnorat, Y.

    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 appro-priate 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 micro-structural instability. Further improvements in creep and crack propagation properties, without signifi-cant 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 Astroloy and is therefore an excellent alloy for modern turbine disk ap-plications.

  11. Powder metallurgy: Solid and liquid phase sintering of copper

    NASA Technical Reports Server (NTRS)

    Sheldon, Rex; Weiser, Martin W.

    1993-01-01

    Basic powder metallurgy (P/M) principles and techniques are presented in this laboratory experiment. A copper based system is used since it is relatively easy to work with and is commercially important. In addition to standard solid state sintering, small quantities of low melting metals such as tin, zinc, lead, and aluminum can be added to demonstrate liquid phase sintering and alloy formation. The Taguchi Method of experimental design was used to study the effect of particle size, pressing force, sintering temperature, and sintering time. These parameters can be easily changed to incorporate liquid phase sintering effects and some guidelines for such substitutions are presented. The experiment is typically carried out over a period of three weeks.

  12. Advanced powder metallurgy aluminum alloys via rapid solidification technology

    NASA Technical Reports Server (NTRS)

    Ray, R.

    1984-01-01

    Aluminum alloys containing 10 to 11.5 wt. pct. of iron and 1.5 to 3 wt. pct. of chromium using the technique of rapid solidification powder metallurgy were studied. Alloys were prepared as thin ribbons (.002 inch thick) rapidly solidified at uniform rate of 10(6) C/second by the melt spinning process. The melt spun ribbons were pulverized into powders (-60 to 400 mesh) by a rotating hammer mill. The powders were consolidated by hot extrusion at a high reduction ratio of 50:1. The powder extrusion temperature was varied to determine the range of desirable processing conditions necessary to yield useful properties. Powders and consolidated alloys were characterized by SEM and optical metallography. The consolidated alloys were evaluated for (1) thermal stability, (2) tensile properties in the range, room temperature to 450 F, and (3) notch toughness in the range, room temperature to 450 F.

  13. Application of superalloy powder metallurgy for aircraft engines

    NASA Technical Reports Server (NTRS)

    Dreshfield, R. L.; Miner, R. V., Jr.

    1980-01-01

    In the last decade, Government/Industry programs have advanced powder metallurgy-near-net-shape technology to permit the use of hot isostatic pressed (HIP) turbine disks in the commercial aircraft fleet. These disks offer a 30% savings of input weight and an 8% savings in cost compared in cast-and-wrought disks. Similar savings were demonstrated for other rotating engine components. A compressor rotor fabricated from hot-die-forged-HIP superalloy billets revealed input weight savings of 54% and cost savings of 35% compared to cast-and-wrought parts. Engine components can be produced from compositions such as Rene 95 and Astroloy by conventional casting and forging, by forging of HIP powder billets, or by direct consolidation of powder by HIP. However, each process produces differences in microstructure or introduces different defects in the parts. As a result, their mechanical properties are not necessarily identical. Acceptance methods should be developed which recognize and account for the differences.

  14. Phase Stability of a Powder Metallurgy Disk Superalloy

    NASA Technical Reports Server (NTRS)

    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.

  15. Ceramic Inclusions In Powder Metallurgy Disk Alloys: Characterization and Modeling

    NASA Technical Reports Server (NTRS)

    Bonacuse, Pete; Kantzos, Pete; Telesman, Jack

    2002-01-01

    Powder metallurgy alloys are increasingly used in gas turbine engines, especially as the material chosen for turbine disks. Although powder metallurgy materials have many advantages over conventionally cast and wrought alloys (higher strength, higher temperature capability, etc.), they suffer from the rare occurrence of ceramic defects (inclusions) that arise from the powder atomization process. These inclusions can have potentially large detrimental effect on the durability of individual components. An inclusion in a high stress location can act as a site for premature crack initiation and thereby considerably reduce the fatigue life. Because these inclusions are exceedingly rare, they usually don't reveal themselves in the process of characterizing the material for a particular application (the cumulative volume of the test bars in a fatigue life characterization is typically on the order of a single actual component). Ceramic inclusions have, however, been found to be the root cause of a number of catastrophic engine failures. To investigate the effect of these inclusions in detail, we have undertaken a study where a known population of ceramic particles, whose composition and morphology are designed to mimic the 'natural' inclusions, are added to the precursor powder. Surface connected inclusions have been found to have a particularly large detrimental effect on fatigue life, therefore the volume of ceramic 'seeds' added is calculated to ensure that a minimum number will occur on the surface of the fatigue test bars. Because the ceramic inclusions are irregularly shaped and have a tendency to break up in the process of extrusion and forging, a method of calculating the probability of occurrence and expected intercepted surface and embedded cross-sectional areas were needed. We have developed a Monte Carlo simulation to determine the distributions of these parameters and have verified the simulated results with observations of ceramic inclusions found in macro

  16. Enterprise Education as Pedagogy

    ERIC Educational Resources Information Center

    Jones, Brian; Iredale, Norma

    2010-01-01

    Purpose: This paper seeks to suggest that the most appropriate way to construe the concept of enterprise education is from a pedagogical viewpoint. Enterprise education as pedagogy is argued to be the most appropriate way to think about the concept and serves to demarcate it from entrepreneurship education, which is very much about business…

  17. The Enterprise Compass

    ERIC Educational Resources Information Center

    McCardle, Ken

    2005-01-01

    As a CIO leading an IT department through change and reorganization, the author developed the Enterprise Compass--a four-point guide to reaching goals and focusing achievement. The Enterprise Compass directs staff to look forward to future accomplishment, back for performance assessments, across campus for better understanding of practical working…

  18. Survey of Micro Enterprise.

    ERIC Educational Resources Information Center

    European Social Fund, Dublin (Ireland).

    Government support of microenterprise/entrepreneurship in Ireland was examined through structured interviews with 81 of 120 microentrepreneurs (68% response rate) identified as clients of local enterprise support agencies and/or completers of enterprise training and structured interviews with representatives of 25 local, voluntary, and private…

  19. Development in youth enterprises.

    PubMed

    Hamilton, Stephen F; Hamilton, Mary Agnes

    2012-01-01

    Business enterprises run by youth can create jobs and teach the principles of free enterprise but also convey skills that can be used by employees in large companies, as well as political activists and entrepreneurs. Research is needed to test the efficacy of this approach and identify its key components. PMID:22826167

  20. THE CALIFORNIA ENVIRONMENTAL ENTERPRISE

    SciTech Connect

    Ragaini, R.C.; Buckles, R.J.; Goldstein, N.E.; Bramlette, T.T.

    1994-04-01

    THE CALIFORNIA ENVIRONMENTAL ENTERPRISE (CEE) is a joint partnership of: the DOE Laboratories LLNL, LBL, and Sandia; the California Environmental Protection Agency (Cal/EPA); and the Institute of Environmental Solutions (IES). CEE is an independent, non-profit regional function organized and operated in accordance with the Department of Energy (DOE) ``Enterprise`` model developed by the DOE Environmental Management (EM) Strategic Task Force and the Strategic Laboratory Council. The vision of THE CALIFORNIA ENVIRONMENTAL ENTERPRISE is to create new economic opportunities through the advancement of rehabilitative reuse of environmentally impaired property, and through research, development and commercialization of alternative environmental technologies. The mission of THE CALIFORNIA ENVIRONMENTAL ENTERPRISE is to maximize the DOE investment by acting as the catalyst for the rapid development and acceptance of environmental technologies needed for redevelopment of contaminated sites, economic revitalization, and the dissipation of adversarial relationships between the public, regulators, problem-holders, and Federal agencies.

  1. Device for preparing combinatorial libraries in powder metallurgy.

    PubMed

    Yang, Shoufeng; Evans, Julian R G

    2004-01-01

    This paper describes a powder-metering, -mixing, and -dispensing mechanism that can be used as a method for producing large numbers of samples for metallurgical evaluation or electrical or mechanical testing from multicomponent metal and cermet powder systems. It is designed to make use of the same commercial powders that are used in powder metallurgy and, therefore, to produce samples that are faithful to the microstructure of finished products. The particle assemblies produced by the device could be consolidated by die pressing, isostatic pressing, laser sintering, or direct melting. The powder metering valve provides both on/off and flow rate control of dry powders in open capillaries using acoustic vibration. The valve is simple and involves no relative movement, avoiding seizure with fine powders. An orchestra of such valves can be arranged on a building platform to prepare multicomponent combinatorial libraries. As with many combinatorial devices, identification and evaluation of sources of mixing error as a function of sample size is mandatory. Such an analysis is presented. PMID:15244416

  2. TRADITIONAL METALLURGY, NANOTECHNOLOGIES AND STRUCTURAL MATERIALS: A SORBY AWARD LECTURE

    SciTech Connect

    Louthan, M

    2007-07-17

    Traditional metallurgical processes are among the many ''old fashion'' practices that use nanoparticles to control the behavior of materials. Many of these practices were developed long before microscopy could resolve nanoscale features, yet the practitioners learned to manipulate and control microstructural elements that they could neither see nor identify. Furthermore, these early practitioners used that control to modify microstructures and develop desired material properties. Centuries old colored glass, ancient high strength steels and medieval organ pipes derived many of their desirable features through control of nanoparticles in their microstructures. Henry Sorby was among the first to recognize that the properties of rocks, minerals, metals and organic materials were controlled by microstructure. However, Mr. Sorby was accused of the folly of trying to study mountains with a microscope. Although he could not resolve nanoscale microstructural features, Mr. Sorby's observations revolutionized the study of materials. The importance of nanoscale microstructural elements should be emphasized, however, because the present foundation for structural materials was built by manipulating those features. That foundation currently supports several multibillion dollar industries but is not generally considered when the nanomaterials revolution is discussed. This lecture demonstrates that using nanotechnologies to control the behavior of metallic materials is almost as old as the practice of metallurgy and that many of the emergent nanomaterials technologists are walking along pathways previously paved by traditional metallurgists.

  3. Powder metallurgy technology of NiTi shape memory alloy

    NASA Astrophysics Data System (ADS)

    Dutkiewicz, J. M.; Maziarz, W.; Czeppe, T.; Lityńska, L.; Nowacki, W. K.; Gadaj, S. P.; Luckner, J.; Pieczyska, E. A.

    2008-05-01

    Powder metallurgy technology was elaborated for consolidation of shape memory NiTi powders. The shape memory alloy was compacted from the prealloyed powder delivered by Memry SA. The powder shows Ms = 10°C and As = -34°C as results from DSC measurements. The samples were hot pressed in the as delivered spherical particle's state. The hot compaction was performed in a specially constructed vacuum press, at temperature of 680°C and pressure of 400 MPa. The alloy powder was encapsulated in copper capsules prior to hot pressing to avoid oxidation or carbides formation. The alloy after hot vacuum compaction at 680°C (i.e. within the B2 NiTi stability range) has shown similar transformation range as the powder. The porosity of samples compacted in the as delivered state was only 1%. The samples tested in compression up to ɛ = 0.06 have shown partial superelastic effect due to martensitic reversible transform- ation which started at the stress above 300 MPa and returned back to ɛ = 0.015 after unloading. They have shown also a high ultimate compression strength of 1600 MPa. Measurements of the samples temperature changes during the process allowed to detect the temperature increase above 12°C for the strain rate 10-2 s-1 accompanied the exothermic martensite transformation during loading and the temperature decrease related to the reverse endothermic transformation during unloading.

  4. [Possible health effects associated with Pre-Columbian metallurgy].

    PubMed

    Idrovo, Alvaro Javier

    2005-09-01

    In the Old World, several researchers have indicated that adverse health effects were associated with exposure to arsenic, and that this influenced a change in the use of copper-arsenic alloys to others less toxic. This hypothesis was evaluated for three Pre-Columbian metallurgy traditions: Central Andes, Intermediate Area, and West Mexico. The metal artifacts from the Central Andes showed arsenic concentrations similar to those in the Old World (0.5%-1.0%). In the Intermediate Area the values were smallest; however, in West Mexico the arsenic content was very high (7%-25%). In Central Andes arsenical bronze was used initially, but copper-tin alloys when introduced were preferred and distributed throughout the Inca Empire. Osteological and artistic evidences of foot amputations among Moche individuals from Central Andes support the presence of "black foot disease" (a condition associated with arsenic poisoning) among Pre-Columbian populations. In conclusion, the adverse effects of arsenic have been observed in the New World, and that these effects promoted a change toward the use of less toxic alloys. PMID:16276677

  5. Welding metallurgy of nickel alloys in gas turbine components

    SciTech Connect

    Lingenfelter, A. C., LLNL

    1997-05-21

    Materials for gas turbine engines are required to meet a wide range of temperature and stress application requirements. These alloys exhibit a combination of creep resistance, creep rupture strength, yield and tensile strength over a wide temperature range, resistance to environmental attack (including oxidation, nitridation, sulphidation and carburization), fatigue and thermal fatigue resistance, metallurgical stability and useful thermal expansion characteristics. These properties are exhibited by a series of solid-solution-strengthened and precipitation-hardened nickel, iron and cobalt alloys. The properties needed to meet the turbine engine requirements have been achieved by specific alloy additions, by heat treatment and by thermal mechanical processing. A thorough understanding of the metallurgy and metallurgical processing of these materials is imperative in order to successfully fusion weld them. This same basic understanding is required for repair of a component with the added dimension of the potential effects of thermal cycling and environmental exposure the component will have endured in service. This article will explore the potential problems in joining and repair welding these materials.

  6. Putting the enterprise into the enterprise system.

    PubMed

    Davenport, T H

    1998-01-01

    Enterprise systems present a new model of corporate computing. They allow companies to replace their existing information systems, which are often incompatible with one another, with a single, integrated system. By streamlining data flows throughout an organization, these commercial software packages, offered by vendors like SAP, promise dramatic gains in a company's efficiency and bottom line. It's no wonder that businesses are rushing to jump on the ES bandwagon. But while these systems offer tremendous rewards, the risks they carry are equally great. Not only are the systems expensive and difficult to implement, they can also tie the hands of managers. Unlike computer systems of the past, which were typically developed in-house with a company's specific requirements in mind, enterprise systems are off-the-shelf solutions. They impose their own logic on a company's strategy, culture, and organization, often forcing companies to change the way they do business. Managers would do well to heed the horror stories of failed implementations. FoxMeyer Drug, for example, claims that its system helped drive it into bankruptcy. Drawing on examples of both successful and unsuccessful ES projects, the author discusses the pros and cons of implementing an enterprise system, showing how a system can produce unintended and highly disruptive consequences. Because of an ES's profound business implications, he cautions against shifting responsibility for its adoption to technologists. Only a general manager will be able to mediate between the imperatives of the system and the imperatives of the business. PMID:10181586

  7. Indexation Rules for Metallurgy in PASCAL. Original Title: Regles d'Indexation de la Metallurgie'--Technical Note Issued by Informascience--January 1980. Translated by Marie Wallin.

    ERIC Educational Resources Information Center

    Royal Inst. of Tech., Stockholm (Sweden). Library.

    The indexing rules presented are designed for use with a new French-German database on metallurgy being developed under an agreement by CNRS (Centre National de la Recherche Scientifique, Paris) and BAM (Bundesanstalt fur Materialprufung, Berlin). The new database, which will feature multilingual titles and index terms (French-German-English-) and…

  8. Agent-based enterprise integration

    SciTech Connect

    N. M. Berry; C. M. Pancerella

    1998-12-01

    The authors are developing and deploying software agents in an enterprise information architecture such that the agents manage enterprise resources and facilitate user interaction with these resources. The enterprise agents are built on top of a robust software architecture for data exchange and tool integration across heterogeneous hardware and software. The resulting distributed multi-agent system serves as a method of enhancing enterprises in the following ways: providing users with knowledge about enterprise resources and applications; accessing the dynamically changing enterprise; locating enterprise applications and services; and improving search capabilities for applications and data. Furthermore, agents can access non-agents (i.e., databases and tools) through the enterprise framework. The ultimate target of the effort is the user; they are attempting to increase user productivity in the enterprise. This paper describes their design and early implementation and discusses the planned future work.

  9. POWDER METALLURGY TiAl ALLOYS: MICROSTRUCTURES AND PROPERTIES

    SciTech Connect

    Hsiung, L

    2006-12-11

    The microstructures and properties of powder metallurgy TiAl alloys fabricated by hot extrusion of gas-atomized powder at different elevated temperatures were investigated. Microstructure of the alloy fabricated at 1150 C consisted of a mixture of fine ({gamma} + {alpha}{sub 2}) equiaxed grains and coarse ordered B2 grains. Particles of ordered hexagonal {omega} phase were also observed in some B2 grains. The alloy containing B2 grains displayed a low-temperature superplastic behavior: a tensile elongation of 310% was measured when the alloy was tested at 800 C under a strain rate of 2 x 10{sup -5} s{sup -1}. Microstructure of the alloy fabricated at 1250 C consisted of a mixture of fine ({gamma} + {alpha}{sub 2}) equiaxed grains, coarse {alpha}{sub 2} grains, and lamellar ({gamma} + {alpha}{sub 2}) colonies. An observation of stacking faults associated with fine {gamma} lamellae in {alpha}{sub 2} grains reveals that the stacking fault of {alpha}{sub 2} phase plays an important role in the formation of lamellar ({gamma} + {alpha}{sub 2}) colonies. Unlike the alloy fabricated at 1150{sup o}, the alloy fabricated at 1250{sup o} displayed no low-temperature superplasticity, but a tensile elongation of 260% at 1000 C was measured. Microstructure of the alloy fabricated at 1400 C consisted of fully lamellar ({gamma} + {alpha}{sub 2}) colonies with the colony size ranging between 50 {micro}m and 100 {micro}m, in which the width of {gamma} lamella is in a range between 100 nm and 350 nm, and the width of {alpha}{sub 2} lamella is in a range between 10 nm and 50 nm. Creep behavior of the ultrafine lamellar alloy and the effects of alloying addition on the creep resistance of the fully lamellar alloy are also investigated.

  10. Analysing Enterprise Returns on Training.

    ERIC Educational Resources Information Center

    Moy, Janelle; McDonald, Rod

    Recent Australian and overseas studies on evaluation of enterprises' return on training investment (ROTI) were reviewed to identify key issues in encouraging increased evaluation of training benefits by enterprises and successful approaches that may inform future "enterprise-friendly" studies of ROTI. It was concluded that more practical,…

  11. Elevated temperature crack growth in advanced powder metallurgy aluminum alloys

    NASA Technical Reports Server (NTRS)

    Porr, William C., Jr.; Gangloff, Richard P.

    1990-01-01

    Rapidly solidified Al-Fe-V-Si powder metallurgy alloy FVS0812 is among the most promising of the elevated temperature aluminum alloys developed in recent years. The ultra fine grain size and high volume fraction of thermally stable dispersoids enable the alloy to maintain tensile properties at elevated temperatures. In contrast, this alloy displays complex and potentially deleterious damage tolerant and time dependent fracture behavior that varies with temperature. J-Integral fracture mechanics were used to determine fracture toughness (K sub IC) and crack growth resistance (tearing modulus, T) of extruded FVS0812 as a function of temperature. The alloy exhibits high fracture properties at room temperature when tested in the LT orientation, due to extensive delamination of prior ribbon particle boundaries perpendicular to the crack front. Delamination results in a loss of through thickness constraint along the crack front, raising the critical stress intensity necessary for precrack initiation. The fracture toughness and tensile ductility of this alloy decrease with increasing temperature, with minima observed at 200 C. This behavior results from minima in the intrinsic toughness of the material, due to dynamic strain aging, and in the extent of prior particle boundary delaminations. At 200 C FVS0812 fails at K levels that are insufficient to cause through thickness delamination. As temperature increases beyond the minimum, strain aging is reduced and delamination returns. For the TL orientation, K (sub IC) decreased and T increased slightly with increasing temperature from 25 to 316 C. Fracture in the TL orientation is governed by prior particle boundary toughness; increased strain localization at these boundaries may result in lower toughness with increasing temperature. Preliminary results demonstrate a complex effect of loading rate on K (sub IC) and T at 175 C, and indicate that the combined effects of time dependent deformation, environment, and strain aging

  12. Testing of electroformed deposited iridium/powder metallurgy rhenium rockets

    NASA Technical Reports Server (NTRS)

    Reed, Brian D.; Dickerson, Robert

    1996-01-01

    High-temperature, oxidation-resistant chamber materials offer the thermal margin for high performance and extended lifetimes for radiation-cooled rockets. Rhenium (Re) coated with iridium (Ir) allow hours of operation at 2200 C on Earth-storable propellants. One process for manufacturing Ir/Re rocket chambers is the fabrication of Re substrates by powder metallurgy (PM) and the application of Ir coatings by using electroformed deposition (ED). ED Ir coatings, however, have been found to be porous and poorly adherent. The integrity of ED Ir coatings could be improved by densification after the electroforming process. This report summarizes the testing of two 22-N, ED Ir/PM Re rocket chambers that were subjected to post-deposition treatments in an effort to densify the Ir coating. One chamber was vacuum annealed, while the other chamber was subjected to hot isostatic pressure (HIP). The chambers were tested on gaseous oxygen/gaseous hydrogen propellants, at mixture ratios that simulated the oxidizing environments of Earth-storable propellants. ne annealed ED Ir/PM Re chamber was tested for a total of 24 firings and 4.58 hr at a mixture ratio of 4.2. After only 9 firings, the annealed ED Ir coating began to blister and spall upstream of the throat. The blistering and spalling were similar to what had been experienced with unannealed, as-deposited ED Ir coatings. The HIP ED Ir/PM Re chamber was tested for a total of 91 firings and 11.45 hr at mixture ratios of 3.2 and 4.2. The HIP ED Ir coating remained adherent to the Re substrate throughout testing; there were no visible signs of coating degradation. Metallography revealed, however, thinning of the HIP Ir coating and occasional pores in the Re layer upstream of the throat. Pinholes in the Ir coating may have provided a path for oxidation of the Re substrate at these locations. The HIP ED Ir coating proved to be more effective than vacuum annealed and as-deposited ED Ir. Further densification is still required to

  13. Investigation of the Environmental Durability of a Powder Metallurgy Material

    NASA Technical Reports Server (NTRS)

    Ward, LaNita D.

    2004-01-01

    PM304 is a NASA-developed composite powder metallurgy material that is being developed for high temperature applications such as bushings in high temperature industrial furnace conveyor systems. My goal this summer was to analyze and evaluate the effects that heat exposure had on the PM304 material at 500 C and 650 C. The material is composed of Ni-Cr, Ag, Cr2O3, and eutectic BaF2-CaF2. PM304 is designed to eliminate the need for oil based lubricants in high temperature applications, while reducing friction and wear. However, further investigation was needed to thoroughly examine the properties of PM304. The effects of heat exposure on PM304 bushings were investigated. This investigation was necessary due to the high temperatures that the material would be exposed to in a typical application. Each bushing was cut into eight sections. The specimens were heated to 500 C or 650 C for time intervals from 1 hr to 5,000 hrs. Control specimens were kept at room temperature. Weight and thickness measurements were taken before and after the bushing sections were exposed to heat. Then the heat treated specimens were mounted and polished side by side with the control specimens. This enabled optical examination of the material's microstructure using a metallograph. The specimens were also examined with a scanning electron microscope (SEM). The microstructures were compared to observe the effects of the heat exposure. Chemical analysis was done to investigate the interactions between Ni-Cr and BaF2-CaF2 and between Cr2O3 and BaF2-CaF2 at high temperature. To observe this, the two compounds that were being analyzed were mixed in a crucible in varied weight percentages and heated to 1100 C in a furnace for approximately two hours. Then the product was allowed to cool and was then analyzed by X-ray diffraction. Interpretation of the results is in progress.

  14. The Higher Education Enterprise.

    ERIC Educational Resources Information Center

    Ottinger, Cecilia A.

    1991-01-01

    Higher education not only contributes to the development of the human resources and intellectual betterment of the nation but is also a major economic enterprise. This research brief reviews and highlights data on the size and growth of higher education and illustrates how higher education institutions are preparing the future labor force. It…

  15. Knowledge Management as Enterprise

    ERIC Educational Resources Information Center

    Kutay, Cat

    2007-01-01

    Indigenous people have been for a long time deprived of financial benefit from their knowledge. Campaigns around the stolen wages and the "Pay the Rent" campaign highlight this. As does the endemic poverty and economic disenfranchisement experienced by many Indigenous people and communities in Australia. Recent enterprises developed by Indigenous…

  16. The Enterprise Foundation.

    ERIC Educational Resources Information Center

    Szablya, Helen

    This document describes five demonstration programs administered by the Enterprise Foundation in the Washington, D.C., area. The purpose of the Partners for Success Program is to support and assist hard-to-employ jobseekers in setting and achieving both professional and personal goals. The Words for Life Program is a workplace literacy project to…

  17. Education and Enterprise.

    ERIC Educational Resources Information Center

    Emery, John S.

    1987-01-01

    In Australia, one effect of reduced government funding is to stimulate enterprise in higher education. This paper supports extending cooperation and joint ventures with industry and commerce and initiating new practices, such as exporting educational services or establishing a private education sector. A major drawback is the equity issue.…

  18. Advances in powder metallurgy - 1991. Vol. 5 - P/M materials; Proceedings of the Powder Metallurgy Conference and Exhibition, Chicago, IL, June 9-12, 1991

    SciTech Connect

    Pease, L.F. III; Sansoucy, R.J.

    1991-01-01

    The present volume powder metallurgy materials discusses the state of the PM industry, a metallurgical evaluation of new steel powders, design criteria for the manufacturing of low-alloy steel powders, and homogenization processing of a PM maraging steel. Attention is given to the corrosion resistance of full density sintered 316 SS, the performance characteristics of a new sinter-hardening low-alloy steel, wear performance of compositions made by low alloy iron/high alloy powder mixtures, and the strengthening of an AISI 1020 steel by aluminum-microalloying during liquid dynamic compaction. Topics addressed include the influence of alloying on the properties of water-atomized copper powders, fundamentals of high pressure gas atomization process control, advanced sensors and process control of gas atomization, and bimetallic tubulars via spray forming. Also discussed are factors affecting the delamination of PM molybdenum during stamping, applications of powder metallurgy molybdenum in the 1990s, and powder processing of high-temperature oxides.

  19. The Application of Thermal Plasma to Extraction Metallurgy and Related Fields

    NASA Technical Reports Server (NTRS)

    Akashi, K.

    1980-01-01

    Various applications of thermal plasma to extraction metallurgy and related fields are surveyed, chiefly on the basis of documents published during the past two or three years. Applications to melting and smelting, to thermal decomposition, to reduction, to manufacturing of inorganic compounds, and to other fields are considered.

  20. Mechanical properties of modified low cobalt powder metallurgy Udimet 700 type alloys

    NASA Technical Reports Server (NTRS)

    Harf, Fredric H.

    1989-01-01

    Eight superalloys derived from Udimet 700 were prepared by powder metallurgy, hot isostatically pressed, heat treated and their tensile and creep rupture properties determined. Several of these alloys displayed properties superior to those of Udimet 700 similarly prepared, in one case exceeding the creep rupture life tenfold. Filter clogging by extracted gamma prime, its measurement and significance are discussed in an appendix.

  1. The role of chemical metallurgy in the emerging field of materials science and engineering

    NASA Astrophysics Data System (ADS)

    Chang, Y. Austin

    1994-12-01

    Materials science and engineering has been emerging as a unique academic discipline during the last decade and a half. The role of chemical metallurgy in this emerging field is not well defined, yet it has played an important historical role in the intellectual development of the discipline of metallurgical engineering in terms of teaching, research, and technological appli-cations. In this lecture, I have attempted to define the role of chemical metallurgy in this emerg-ing field and, moreover, to propose using the broader term “chemical processing of material” instead of chemical metallurgy. The role is to educate materials scientists and engineers at the baccalaureate degree level as well as the graduate degree level. I believe that if materials sci-entists and engineers have a good grasp of the principles of chemical processing of materials, they will be in an excellent position to tackle many of the challenging and important problems facing us in the materials field. I have also given in this lecture three diverse examples of materials problems that have been studied using the basic principles of chemical processing of materials. These examples are used to demonstrate that the tools of chemical metallurgy can be used effectively to study many contemporary materials science and engineering problems.

  2. Powder metallurgy approaches to high temperature components for gas turbine engines

    NASA Technical Reports Server (NTRS)

    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.

  3. Power metallurgy approaches to high temperature components for gas turbine engines

    NASA Technical Reports Server (NTRS)

    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.

  4. A Guide for Planning Facilities for Occupational Preparation Programs in Metallurgy Technology. Interim Report. Research 28.

    ERIC Educational Resources Information Center

    German, Carl, Jr.

    The major purpose of this guide is to elicit the information necessary for writing educational specifications for facilities to house technical education programs in metallurgy. It is organized in these parts: (1) Part I discusses the major purpose, underlying assumptions, recent instructional trends, and guiding principles utilized in the…

  5. Solvent Extraction of Copper: An Extractive Metallurgy Exercise for Undergraduate Teaching Laboratories

    ERIC Educational Resources Information Center

    Smellie, Iain A.; Forgan, Ross S.; Brodie, Claire; Gavine, Jack S.; Harris, Leanne; Houston, Daniel; Hoyland, Andrew D.; McCaughan, Rory P.; Miller, Andrew J.; Wilson, Liam; Woodhall, Fiona M.

    2016-01-01

    A multidisciplinary experiment for advanced undergraduate students has been developed in the context of extractive metallurgy. The experiment serves as a model of an important modern industrial process that combines aspects of organic/inorganic synthesis and analysis. Students are tasked to prepare a salicylaldoxime ligand and samples of the…

  6. Iron's Role in Aluminum: A Powder Metallurgy and Sustainability Approach

    NASA Astrophysics Data System (ADS)

    Saller, Brandon Dale

    cryomilling. With respect to the powder, a differential scanning calorimetry and activation energy analysis elucidated the formation and phase transformation temperatures of the relevant intermetallic phases, and the microstructural factors that influenced them. With an understanding of the fundamental science behind the intermetallic formation in the Al-Fe system, the composition of helium atomized Al-2at.% Fe was chosen combined with high-pressure torsion processing to yield a bulk alloy that demonstrated an ultimate tensile strength of 488 MPa. This strength was achieved via a combination of two mechanisms: grain refinement (Hall-Petch) and dislocation-Al6Fe interactions (Orowan strengthening), with notable thermal stability present up until 450°C. Finally, the potential for Al-Fe as a sustainable alloy was studied and a link established between current environmental literature and metallurgy literature on the potential for incorporation of Fe into Al to create a structural alloy.

  7. Procedure improvement enterprises

    SciTech Connect

    Davis, P.L.

    1992-01-01

    At Allied-Signal's Kansas City Division (KCD), we recognize the importance of clear, concise and timely procedures for sharing information, promoting consistency and documenting the way we do business. For these reasons, the KCD has gathered a team of employees to analyze the process we currently use to publish procedures, identify the procedure needs of KCD employees, and design a system that meets or exceeds the requirements and expectations of DOE. The name of our group is the Procedure Improvement Enterprise Critical Process Team, or PIE CPT. The mission statement of Procedure Improvement Enterprise is to develop and implement within the Kansas City Division an effective nd flexible procedure system that will establish a model of excellence, will emphasize team work and open communication, and will ensure compliance with corporate/government requirements.

  8. Procedure improvement enterprises

    SciTech Connect

    Davis, P.L.

    1992-01-01

    At Allied-Signal`s Kansas City Division (KCD), we recognize the importance of clear, concise and timely procedures for sharing information, promoting consistency and documenting the way we do business. For these reasons, the KCD has gathered a team of employees to analyze the process we currently use to publish procedures, identify the procedure needs of KCD employees, and design a system that meets or exceeds the requirements and expectations of DOE. The name of our group is the Procedure Improvement Enterprise Critical Process Team, or PIE CPT. The mission statement of Procedure Improvement Enterprise is to develop and implement within the Kansas City Division an effective nd flexible procedure system that will establish a model of excellence, will emphasize team work and open communication, and will ensure compliance with corporate/government requirements.

  9. 2015 Enterprise Strategic Vision

    SciTech Connect

    2015-08-01

    This document aligns with the Department of Energy Strategic Plan for 2014-2018 and provides a framework for integrating our missions and direction for pursuing DOE’s strategic goals. The vision is a guide to advancing world-class science and engineering, supporting our people, modernizing our infrastructure, and developing a management culture that operates a safe and secure enterprise in an efficient manner.

  10. The Shuttle Enterprise

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The Shuttle Enterprise rolls out of the Palmdale manufacturing facilities with Star Trek television cast members. From left to right they are: Dr. James D. Fletcher, NASA Administrator, DeForest Kelley (Dr. 'Bones' McCoy), George Takei (Mr. Sulu), Nichelle Nichols (Lt. Uhura), Leonard Nimoy (the indefatigable Mr. Spock), Gene Rodenberry (The Great Bird of the Galaxy), and Walter Koenig (Ensign Pavel Checkov).

  11. High field performance of superconducting magnets using powder metallurgy processed Cu-Nb-Sn and Nb-Al

    SciTech Connect

    Zaleski, A.J.; Foner, S.

    1984-06-01

    Small superconducting magnets were fabricated with powder metallurgy processed Nb-Al wire and with powder metallurgy processed multistrand Cu-Nb--Sn wire with 19 tin cores. Tests in a background field of up to 15 T showed that short sample characteristics were achieved for three coils. Upper limits of resistivity were established for both powder metallurgy processed wires. The reacted wires in the magnets gave upper limits of resistivity at 10 T of less than 1.4 x 10/sup -14/ ..cap omega.. cm for the Nb/sub 3/Sn wire, and less than 9 x 10/sup -13/ ..cap omega.. cm for the Nb-Al wire.

  12. Grand Challenges of Enterprise Integration

    SciTech Connect

    Brosey, W.D; Neal, R.E.; Marks, D.

    2001-04-01

    Enterprise Integration connects and combines people, processes, systems, and technologies to ensure that the right people and the right processes have the right information and the right resources at the right time. A consensus roadmap for Technologies for Enterprise Integration was created as part of an industry/government/academia partnership in the Integrated Manufacturing Technology Initiative (IMTI). Two of the grand challenges identified by the roadmapping effort will be addressed here--Customer Responsive Enterprises and Totally Connected Enterprises. Each of these challenges is briefly discussed as to the current state of industry and the future vision as developed in the roadmap.

  13. Metals in Past Societies: A Global Perspective on Indigenous African Metallurgy Shadreck Chirikure

    SciTech Connect

    Devanathan, Ram

    2015-10-01

    This slim book (166 pages) shines a spotlight on pre-industrial African metallurgy, its global connections, and anthropological implications. It integrates seemingly disparate disciplines, such as history, geology, ethnography, archeology, and metallurgy, to illustrate the diversity and innovation in metallurgy across Africa and the role of metals in the rise of socio-economic inequalities and political power. The book has 7 chapters and the focus on metals as enablers of human needs and wants is evident in each chapter. The first chapter presents the context of the work and data sources. The second chapter focuses on the origin and development of mining and metallurgy in pre-industrial Africa. Chapter 3 is dedicated to the interaction of nature and culture in the process of mining. Chapter 4 deals with the transformation of the ore into metal by smelting and the sociocultural aspects of this process. Chapter 5 explores the social and cultural roles acquired by metals as a result of fabrication into objects. Chapter 6 examines the social role of metals, trade in metals, cultural contact, proto-globalization, and technology transfer. Finally, Chapter 7 draws lessons for global anthropology from the African experience. The sources of information are adequately cited and the long list of references at the end of each chapter will be a boon to researchers in this field. The author highlights the cultural aspects and social context of the adoption of metallurgy in Africa while drawing parallels between practices in pre-industrial Africa and those in other parts of the world. The book is peppered with delightful vignettes that offer insights into the process of transforming nature into culturally significant objects. For instance, African miners, like their counterparts in Nepal and Latin America, called upon deities, spirits and ancestors to mediate between nature and humans. Women had distinct roles in this process, but there were variations in these roles and in the

  14. NASA Enterprise Visual Analysis

    NASA Technical Reports Server (NTRS)

    Lopez-Tellado, Maria; DiSanto, Brenda; Humeniuk, Robert; Bard, Richard, Jr.; Little, Mia; Edwards, Robert; Ma, Tien-Chi; Hollifield, Kenneith; White, Chuck

    2007-01-01

    NASA Enterprise Visual Analysis (NEVA) is a computer program undergoing development as a successor to Launch Services Analysis Tool (LSAT), formerly known as Payload Carrier Analysis Tool (PCAT). NEVA facilitates analyses of proposed configurations of payloads and packing fixtures (e.g. pallets) in a space shuttle payload bay for transport to the International Space Station. NEVA reduces the need to use physical models, mockups, and full-scale ground support equipment in performing such analyses. Using NEVA, one can take account of such diverse considerations as those of weight distribution, geometry, collision avoidance, power requirements, thermal loads, and mechanical loads.

  15. Space Science Enterprise Strategy

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The 2003 Space Science Enterprise Strategy represents the efforts of hundreds of scientists, staff, and educators, as well as collaboration with the other NASA Enterprises. It reveals the progress we have made, our plans for the near future, and our opportunity to support the Agency's Mission to "explore the universe and search for life." Space science has made spectacular advances in the recent past, from the first baby pictures of the universe to the discovery of water ice on Mars. Each new discovery impels us to ask new questions or regard old ones in new ways. How did the universe begin? How did life arise? Are we alone? These questions continue to inspire all of us to keep exploring and searching. And, as we get closer to answers, we will continue to share our findings with the science community, educators, and the public as broadly and as rapidly as possible. In this Strategy, you will find science objectives that define NASA's quest for discovery. You will also find the framework of programs, such as flight missions and ground-based research, that will enable us to achieve these objectives. This Strategy is founded on recommendations from the community, as well as lessons learned from past programs, and maps the stepping-stones to the future of space science.

  16. Enterprise Skills for the Economy

    ERIC Educational Resources Information Center

    Galloway, Laura; Anderson, Maggie; Brown, Wendy; Wilson, Laura

    2005-01-01

    Purpose ? In response to the emergence of an enterprise economy, government claims that building an enterprise culture is vital. Correspondingly, provision of entrepreneurship education in higher education has expanded. The paper aims to assess the potential of entrepreneurship education to develop skills, and of whether students perceive them as…

  17. Virtual Enterprise: Transforming Entrepreneurship Education

    ERIC Educational Resources Information Center

    Borgese, Anthony

    2011-01-01

    Entrepreneurship education is ripe for utilizing experiential learning methods. Experiential methods are best learned when there is constant immersion into the subject matter. One such transformative learning methodology is Virtual Enterprise (VE). Virtual Enterprise is a multi-faceted, experiential learning methodology disseminated by the City…

  18. An introduction to enterprise modeling and simulation

    SciTech Connect

    Ostic, J.K.; Cannon, C.E.

    1996-09-01

    As part of an ongoing effort to continuously improve productivity, quality, and efficiency of both industry and Department of Energy enterprises, Los Alamos National Laboratory is investigating various manufacturing and business enterprise simulation methods. A number of enterprise simulation software models are being developed to enable engineering analysis of enterprise activities. In this document the authors define the scope of enterprise modeling and simulation efforts, and review recent work in enterprise simulation at Los Alamos National Laboratory as well as at other industrial, academic, and research institutions. References of enterprise modeling and simulation methods and a glossary of enterprise-related terms are provided.

  19. Investigation of machinability of iron based metal matrix composite (MMC) powder metallurgy parts

    NASA Astrophysics Data System (ADS)

    Szalay, Tibor; Czampa, Miklós; Markos, Sándor; Farkas, Balázs

    2012-09-01

    One of the advantages of powder metallurgy technology is that we may produce the final geometry of the required part saving considerable time and cost. However there are several applications that require parts need additional machining for example when the product contains threads, cross bore or slots. In these cases cutting of the hard and porous material may causes difficulties in manufacturing. The aim of the introduced research is the experimental investigation of the machinability of the iron based MMC powder metallurgy parts, determining the favourable composition of the powder and advantageous process parameters regarding the properties of the machinability. The research try to answer to the challenge of the poorly defined expression: machinability, and after defining the features and methods of the evaluation we develop advises for the proper technology parameters.

  20. Preparation of Three-Dimensional Graphene Foams Using Powder Metallurgy Templates.

    PubMed

    Sha, Junwei; Gao, Caitian; Lee, Seoung-Ki; Li, Yilun; Zhao, Naiqin; Tour, James M

    2016-01-26

    A simple and scalable method which combines traditional powder metallurgy and chemical vapor deposition is developed for the synthesis of mesoporous free-standing 3D graphene foams. The powder metallurgy templates for 3D graphene foams (PMT-GFs) consist of particle-like carbon shells which are connected by multilayered graphene that shows high specific surface area (1080 m(2) g(-1)), good crystallization, good electrical conductivity (13.8 S cm(-1)), and a mechanically robust structure. The PMT-GFs did not break under direct flushing with DI water, and they were able to recover after being compressed. These properties indicate promising applications of PMT-GFs for fields requiring 3D carbon frameworks such as in energy-based electrodes and mechanical dampening. PMID:26678869

  1. [Use of powder metallurgy for development of implants of Co-Cr-Mo alloy powder].

    PubMed

    Dabrowski, J R

    2001-04-01

    This paper discusses the application of powder metallurgy for the development of porous implantation materials. Powders obtained from Co-Cr-Mo alloy with different carbon content by water spraying and grinding, have been investigated. Cold pressing and rotary re-pressing methods were used for compressing the powder. It was found that the sintered materials obtained from water spraying have the most advantageous properties. PMID:11388037

  2. Environmental concerns in extractive metallurgy. (Latest citations from METADEX). Published Search

    SciTech Connect

    Not Available

    1994-09-01

    The bibliography contains citations concerning pollution control in the extractive metallurgical industry. Articles discuss disposal of waste solids resulting from ore processing, treatment of waste water, recovery of particulate fines, material recovery from waste water, and remediation of waste streams from extractive metallurgy. Citations address processing of copper, gold, zinc, uranium, iron, lead, and other metal materials and metal-bearing ores. (Contains a minimum of 152 citations and includes a subject term index and title list.)

  3. Hydrogen halide cleaning of powder metallurgy nickel-20 chromium-3 thoria.

    NASA Technical Reports Server (NTRS)

    Herbell, T. P.

    1972-01-01

    The Cr2O3 content of powder metallurgy nickel-20 chromium-3 thoria was reduced with atmospheres consisting of hydrogen plus hydrogen chloride (HCl) or hydrogen bromide (HBr). The nonthoria oxygen content or 'oxygen excess' was reduced from an initial amount of greater than 50,000 ppm to less than 100 ppm. Low temperatures were effective, but lowest oxygen levels were achieved with the highest cleaning temperature of 1200 C.

  4. LACBED characterization of dislocations in Cu-Al-Ni shape memory alloys processed by powder metallurgy

    NASA Astrophysics Data System (ADS)

    Rodriguez, P. P.; Ibarra, A.; San Jean, J.; Morniro, J. P.; No, M. L.

    2003-10-01

    Powder metallurgy Cu-AI-Ni shape memory alloys show excellent thermomechanical properties, being the fracture behavior close to the one observed in single crystals. However, the microstructural mechanisms responsible of such behavior are still under study. In this paper we present the characterization of the dislocations present in these alloys by Large Angle Convergent Beam Electron Diffraction (LACBED) in two different stages of the elaboration process: after HIP compaction and after hot rolling.

  5. Properties of WZ21 (%wt) alloy processed by a powder metallurgy route.

    PubMed

    Cabeza, Sandra; Garcés, Gerardo; Pérez, Pablo; Adeva, Paloma

    2015-06-01

    Microstructure, mechanical properties and corrosion behaviour of WZ21 (%wt) alloy prepared by a powder metallurgy route from rapidly solidified powders have been studied. Results were compared to those of the same alloy prepared through a conventional route of casting and extrusion. The microstructure of the extruded ingot consisted of α-Mg grains and Mg3Zn3Y2 (W-phase) and LPSO-phase particles located at grain boundaries. Moreover, stacking faults were also observed within α-Mg grains. The alloy processed by the powder metallurgy route exhibited a more homogeneous and finer microstructure, with a grain size of 2 μm. In this case W-phase and Mg24Y5 phase were identified, but not the LPSO-phase. The microstructural refinement induced by the use of rapidly solidified powders strengthened the alloy at room temperature and promoted superplasticity at higher strain rates. Corrosion behaviour in PBS medium evidenced certain physical barrier effect of the almost continuous arrangements of second phases aligned along the extrusion direction in conventionally processed WZ21 alloy, with a stable tendency around 7 mm/year. On the other hand, powder metallurgy processing promoted significant pitting corrosion, inducing accelerated corrosion rate during prolonged immersion times. PMID:25792409

  6. Enterprise Reference Library

    NASA Technical Reports Server (NTRS)

    Bickham, Grandin; Saile, Lynn; Havelka, Jacque; Fitts, Mary

    2011-01-01

    Introduction: Johnson Space Center (JSC) offers two extensive libraries that contain journals, research literature and electronic resources. Searching capabilities are available to those individuals residing onsite or through a librarian s search. Many individuals have rich collections of references, but no mechanisms to share reference libraries across researchers, projects, or directorates exist. Likewise, information regarding which references are provided to which individuals is not available, resulting in duplicate requests, redundant labor costs and associated copying fees. In addition, this tends to limit collaboration between colleagues and promotes the establishment of individual, unshared silos of information The Integrated Medical Model (IMM) team has utilized a centralized reference management tool during the development, test, and operational phases of this project. The Enterprise Reference Library project expands the capabilities developed for IMM to address the above issues and enhance collaboration across JSC. Method: After significant market analysis for a multi-user reference management tool, no available commercial tool was found to meet this need, so a software program was built around a commercial tool, Reference Manager 12 by The Thomson Corporation. A use case approach guided the requirements development phase. The premise of the design is that individuals use their own reference management software and export to SharePoint when their library is incorporated into the Enterprise Reference Library. This results in a searchable user-specific library application. An accompanying share folder will warehouse the electronic full-text articles, which allows the global user community to access full -text articles. Discussion: An enterprise reference library solution can provide a multidisciplinary collection of full text articles. This approach improves efficiency in obtaining and storing reference material while greatly reducing labor, purchasing and

  7. Enterprise data environment

    SciTech Connect

    Ricketts, B.

    1994-12-31

    This paper will report the progress of M3i`s evaluation of the communication challenges facing their client base and offer evidence that the puzzle is about to be solved. This paper will introduce the Enterprise Data Environment. In order to create a basis for Enterprise Data Environment (EDE), the fundamental data bases created and maintained by an average electrical utility must be discussed. The AM/FM industry began almost 30 years ago while the first {open_quotes}fast-pencil{close_quotes} system dates back to the 1960`s. The industry, which has undergone a series of transitions and name changes over the years, had its beginning as Computer Aided Drafting (CAD). As the name suggests, the technology drew lines and circles and was a tool for a draftsperson. One extension to CAD was Computer Assisted Mapping (CAD/CAM). This extension to CAD led to the creation of maps and was the technology renamed Automated Mapping (AM). One of the reasons for the name change was CAM also stood for Computer Aided Manufacturing. When data bases became more robust and popular (in the 1970`s), the natural extension to CAM (Computer Assisted Mapping) was to add a data base of the structures and facilities represented on the maps. Since data bases are managed, the technology was logically called Facilities Management (FM). Hence, Automated Mapping/Facilities Management or AM/FM. It is also called Geographic Information Systems or GIS. The main problem with AM/FM is that the data bases are created, maintained and updated by draftspersons from the AM perspective. Traditionally, these data bases have been as much as six months out-of-date. Because a utility relies on up-to-date data, it might be wondered how any work was achieved with AM/FM.

  8. Enterprise Middleware for Scientific Data

    SciTech Connect

    Thomson, Judi; Chappell, Alan R.; Almquist, Justin P.

    2003-02-27

    We describe an enterprise middleware system that integrates, from a user’s perspective, data located on disparate data storage devices without imposing additional requirements upon those storage mechanisms. The system provides advanced search capabilities by exploiting a repository of metadata that describes the integrated data. This search mechanism integrates information from a collection of XML metadata documents with diverse schema. Users construct queries using familiar search terms, and the enterprise system uses domain representations and vocabulary mappings to translate the user’s query, expanding the search to include other potentially relevant data. The enterprise architecture allows flexibility with respect to domain dependent processing of user data and metadata

  9. State Enterprise Zone Programs: Have They Worked?

    ERIC Educational Resources Information Center

    Peters, Alan H.; Fisher, Peter S.

    The effectiveness of state enterprise zone programs was examined by using a hypothetical-firm model called the Tax and Incentives Model-Enterprise Zones (TAIM-ez) model to analyze the value of enterprise zone incentives to businesses across the United States and especially in the 13 states that had substantial enterprise zone programs by 1990. The…

  10. Enterprise Training: This Changes Everything.

    ERIC Educational Resources Information Center

    Stamps, David

    1999-01-01

    In many companies, training management and knowledge management are merging. Enterprise-resource-planning software products promise seamless integration of all information flowing through a company. Training then becomes part of a process, not a course or event. (SK)

  11. Maturity model for enterprise interoperability

    NASA Astrophysics Data System (ADS)

    Guédria, Wided; Naudet, Yannick; Chen, David

    2015-01-01

    Historically, progress occurs when entities communicate, share information and together create something that no one individually could do alone. Moving beyond people to machines and systems, interoperability is becoming a key factor of success in all domains. In particular, interoperability has become a challenge for enterprises, to exploit market opportunities, to meet their own objectives of cooperation or simply to survive in a growing competitive world where the networked enterprise is becoming a standard. Within this context, many research works have been conducted over the past few years and enterprise interoperability has become an important area of research, ensuring the competitiveness and growth of European enterprises. Among others, enterprises have to control their interoperability strategy and enhance their ability to interoperate. This is the purpose of the interoperability assessment. Assessing interoperability maturity allows a company to know its strengths and weaknesses in terms of interoperability with its current and potential partners, and to prioritise actions for improvement. The objective of this paper is to define a maturity model for enterprise interoperability that takes into account existing maturity models while extending the coverage of the interoperability domain. The assessment methodology is also presented. Both are demonstrated with a real case study.

  12. 78 FR 48468 - Hewlett Packard Company, Hewlett Packard Enterprise Business Unit, EG HP Storage, Enterprise...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-08

    ... Employment and Training Administration Hewlett Packard Company, Hewlett Packard Enterprise Business Unit, EG HP Storage, Enterprise Storage, Servers and Networking Storage, APP Management, Research and... behalf of workers of Hewlett Packard Company, Hewlett Packard Enterprise Business Unit, EG HP...

  13. Building collaborative enterprise.

    PubMed

    Adler, Paul; Heckscher, Charles; Prusak, Laurence

    2011-01-01

    Can large companies be both innovative and efficient? Yes, argue Adler, of the University of Southern California; Heckscher, of Rutgers; and Prusak, an independent consultant. But they must develop new organizational capabilities that will create the atmosphere of trust that knowledge work requires--and the coordinating mechanisms to make it scalable. Specifically, such organizations must learn to: Define a shared purpose that guides what people at all levels of the organization are trying to achieve together; Cultivate an ethic of contribution in which the highest value is accorded to people who look beyond their specific roles and advance the common purpose; Develop scalable procedures for coordinating people's efforts so that process-management activities become truly interdependent; and Create an infrastructure in which individuals' spheres of influence overlap and collaboration is both valued and rewarded. These four goals may sound idealized, but the imperative to achieve them is practical, say the authors. Only the truly collaborative enterprises that can tap into everyone's ideas---in an organized way--will compete imaginatively, quickly, and cost-effectively enough to become the household names of this century. PMID:21800474

  14. Fabrication and characterization of americium, neptunium and curium bearing MOX fuels obtained by powder metallurgy process

    NASA Astrophysics Data System (ADS)

    Lebreton, Florent; Prieur, Damien; Jankowiak, Aurélien; Tribet, Magaly; Leorier, Caroline; Delahaye, Thibaud; Donnet, Louis; Dehaudt, Philippe

    2012-01-01

    MOX fuel pellets containing up to 1.4 wt% of Minor Actinides (MA), i.e. Am, Np and Cm, were fabricated to demonstrate the technical feasibility of powder metallurgy process involving, pelletizing and sintering in controlled atmosphere. The compounds were then characterized using XRD, SEM and EDX/EPMA. Dense pellets were obtained which closed porosity mean size is equal to 7 μm. The results indicate the formation of (U, Pu)O 2 solid solution. However, microstructure contains some isolated UO 2 grains. The distribution of Am and Cm appears to be homogeneous whereas Np was found to be clustered at some locations.

  15. Physical metallurgy: Scientific school of the Academician V.M. Schastlivtsev

    NASA Astrophysics Data System (ADS)

    Tabatchikova, T. I.

    2016-04-01

    This paper is to honor Academician Vadim Mikhailovich Schastlivtsev, a prominent scientist in the field of metal physics and materials science. The article comprises an analysis of the topical issues of the physical metallurgy of the early 21st century and of the contribution of V.M. Schastlivtsev and of his school to the science of phase and structural transformations in steels. In 2015, Vadim Mikhailovich celebrates his 80th birthday, and this paper is timed to this honorable date. The list of his main publications is given in it.

  16. Accelerated Near-Threshold Fatigue Crack Growth Behavior of an Aluminum Powder Metallurgy Alloy

    NASA Technical Reports Server (NTRS)

    Piascik, Robert S.; Newman, John A.

    2002-01-01

    Fatigue crack growth (FCG) research conducted in the near threshold regime has identified a room temperature creep crack growth damage mechanism for a fine grain powder metallurgy (PM) aluminum alloy (8009). At very low DK, an abrupt acceleration in room temperature FCG rate occurs at high stress ratio (R = Kmin/Kmax). The near threshold accelerated FCG rates are exacerbated by increased levels of Kmax (Kmax less than 0.4 KIC). Detailed fractographic analysis correlates accelerated FCG with the formation of crack-tip process zone micro-void damage. Experimental results show that the near threshold and Kmax influenced accelerated crack growth is time and temperature dependent.

  17. Dose and Dose Risk Caused by Natural Phenomena - Proposed Powder Metallurgy Core Manufacturing Facility

    SciTech Connect

    Holmes, W.G.

    2001-08-16

    The offsite radiological effects from high velocity straight winds, tornadoes, and earthquakes have been estimated for a proposed facility for manufacturing enriched uranium fuel cores by powder metallurgy. Projected doses range up to 30 mrem/event to the maximum offsite individual for high winds and up to 85 mrem/event for very severe earthquakes. Even under conservative assumptions on meteorological conditions, the maximum offsite dose would be about 20 per cent of the DOE limit for accidents involving enriched uranium storage facilities. The total dose risk is low and is dominated by the risk from earthquakes. This report discusses this test.

  18. Materials for Advanced Turbine Engines. Volume 1; Power Metallurgy Rene 95 Rotating Turbine Engine Parts

    NASA Technical Reports Server (NTRS)

    Pfouts, W. R.; Shamblen, C. E.; Mosier, J. S.; Peebles, R. E.; Gorsler, R. W.

    1979-01-01

    An attempt was made to improve methods for producing powder metallurgy aircraft gas turbine engine parts from the nickel base superalloy known as Rene 95. The parts produced were the high pressure turbine aft shaft for the CF6-50 engine and the stages 5 through 9 compressor disk forgings for the CFM56/F101 engines. A 50% cost reduction was achieved as compared to conventional cast and wrought processing practices. An integrated effort involving several powder producers and a major forging source were included.

  19. The synthesis and characterization of Mg-Zn-Ca alloy by powder metallurgy process

    NASA Astrophysics Data System (ADS)

    Annur, Dhyah; Franciska P., L.; Erryani, Aprilia; Amal, M. Ikhlasul; Sitorus, Lyandra S.; Kartika, Ika

    2016-04-01

    Known for its biodegradation and biocompatible properties, magnesium alloys have gained many interests to be researched as implant material. In this study, Mg-3Zn-1Ca, Mg-29Zn-1Ca, and Mg-53Zn-4.3Ca (in wt%) were synthesized by means of powder metallurgy method. The compression strength and corrosion resistance of magnesium alloy were thoroughly examined. The microstructures of the alloy were characterized using optical microscopy, Scanning Electron Microscope, and also X-ray diffraction analysis. The corrosion resistance were evaluated using electrochemical analysis. The result indicated that Mg- Zn- Ca alloy could be synthesized using powder metallurgy method. This study showed that Mg-29Zn-1Ca would make the highest mechanical strength up to 159.81 MPa. Strengthening mechanism can be explained by precipitation hardening and grain refinement mechanism. Phase analysis had shown the formation of α Mg, MgO, and intermetallic phases: Mg2Zn11 and also Ca2Mg6Zn3. However, when the composition of Zn reach 53% weight, the mechanical strength will be decreasing. In addition, all of Mg-Zn-Ca alloy studied here had better corrosion resistance (Ecorr around -1.4 VSCE) than previous study of Mg. This study indicated that Mg- 29Zn- 1Ca alloy can be further analyzed to be a biodegradable implant material.

  20. Fatigue-crack propagation in aluminum-lithium alloys processed by power and ingot metallurgy

    SciTech Connect

    Venkateswara Rao, K.T.; Ritchie, R.O. ); Kim, N.J. ); Pizzo, P.P. )

    1990-04-01

    Fatigue-crack propagation behavior in powder-metallurgy (P/M) aluminum-lithium alloys, namely, mechanically-alloyed (MA) Al-4.0Mg-1.5Li-1.1C-0.80{sub 2} (Inco 905-XL) and rapid-solidification-processed (RSP) Al-2.6Li-1.0Cu-0.5Mg-0.5Zr (Allied 644-B) extrusions, has been studied, and results compared with data on an equivalent ingot-metallurgy (I/M) Al-Li alloy, 2090-T81 plate. Fatigue-crack growth resistance of the RSP Al-Li alloy is found to be comparable to the I/M Al-Li alloy; in contrast, crack velocities in MA 905-XL extrusions are nearly three orders of magnitude faster. Growth-rate response in both P/M Al-Li alloys, however, is high anisotropic. Results are interpreted in terms of the microstructural influence of strengthening mechanism, slip mode, grain morphology and texture on the development of crack-tip shielding from crack-path deflection and crack closure. 14 refs., 7 figs., 2 tabs.

  1. Microstructural and mechanical characteristics of porous iron prepared by powder metallurgy.

    PubMed

    Capek, Jaroslav; Vojtěch, Dalibor

    2014-10-01

    The demand for porous biodegradable load-bearing implants has been increasing recently. Based on investigations of biodegradable stents, porous iron may be a suitable material for such applications. In this study, we prepared porous iron samples with porosities of 34-51 vol.% by powder metallurgy using ammonium bicarbonate as a space-holder material. We studied sample microstructure (SEM-EDX and XRD), flexural and compressive behaviors (universal loading machine) and hardness HV5 (hardness tester) of the prepared samples. Sample porosity increased with the amount of spacer in the initial mixtures. Only the pore surfaces had insignificant oxidation and no other contamination was observed. Increasing porosity decreased the mechanical properties of the samples; although, the properties were still comparable with human bone and higher than those of porous non-metallic biomaterials and porous magnesium prepared in a similar way. Based on these results, powder metallurgy appears to be a suitable method for the preparation of porous iron for orthopedic applications. PMID:25175241

  2. Porous titanium scaffolds fabricated using a rapid prototyping and powder metallurgy technique.

    PubMed

    Ryan, Garrett E; Pandit, Abhay S; Apatsidis, Dimitrios P

    2008-09-01

    One of the main issues in orthopaedic implant design is the fabrication of scaffolds that closely mimic the biomechanical properties of the surrounding bone. This research reports on a multi-stage rapid prototyping technique that was successfully developed to produce porous titanium scaffolds with fully interconnected pore networks and reproducible porosity and pore size. The scaffolds' porous characteristics were governed by a sacrificial wax template, fabricated using a commercial 3D-printer. Powder metallurgy processes were employed to generate the titanium scaffolds by filling around the wax template with titanium slurry. In the attempt to optimise the powder metallurgy technique, variations in slurry concentration, compaction pressure and sintering temperature were investigated. By altering the wax design template, pore sizes ranging from 200 to 400 microm were achieved. Scaffolds with porosities of 66.8 +/- 3.6% revealed compression strengths of 104.4+/-22.5 MPa in the axial direction and 23.5 +/- 9.6 MPa in the transverse direction demonstrating their anisotropic nature. Scaffold topography was characterised using scanning electron microscopy and microcomputed tomography. Three-dimensional reconstruction enabled the main architectural parameters such as pore size, interconnecting porosity, level of anisotropy and level of structural disorder to be determined. The titanium scaffolds were compared to their intended designs, as governed by their sacrificial wax templates. Although discrepancies in architectural parameters existed between the intended and the actual scaffolds, overall the results indicate that the porous titanium scaffolds have the properties to be potentially employed in orthopaedic applications. PMID:18556060

  3. Environmental legacy of copper metallurgy and Mongol silver smelting recorded in Yunnan Lake sediments.

    PubMed

    Hillman, Aubrey L; Abbott, Mark B; Yu, JunQing; Bain, Daniel J; Chiou-Peng, TzeHuey

    2015-03-17

    Geochemical measurements on well-dated sediment cores from Lake Er (Erhai) are used to determine the timing of changes in metal concentrations over 4500 years in Yunnan, a borderland region in southwestern China noted for rich mineral deposits but with inadequately documented metallurgical history. Our findings add new insight into the impacts and environmental legacy of human exploitation of metal resources in Yunnan history. We observe an increase in copper at 1500 BC resulting from atmospheric emissions associated with metallurgy. These data clarify the chronological issues related to links between the onset of Yunnan metallurgy and the advent of bronze technology in adjacent Southeast Asia, subjects that have been debated for nearly half a century. We also observe an increase from 1100 to 1300 AD in a number of heavy metals including lead, silver, zinc, and cadmium from atmospheric emissions associated with silver smelting. Culminating during the rule of the Mongols, known as the Yuan Dynasty (1271-1368 AD), these metal concentrations approach levels three to four times higher than those from industrialized mining activity occurring within the catchment today. Notably, the concentrations of lead approach levels at which harmful effects may be observed in aquatic organisms. The persistence of this lead pollution over time created an environmental legacy that likely contributes to known issues in modern day sediment quality. We demonstrate that historic metallurgical production in Yunnan can cause substantial impacts on the sediment quality of lake systems, similar to other paleolimnological findings around the globe. PMID:25685905

  4. Mechanisms of fatigue crack retardation following single tensile overloads in powder metallurgy aluminum alloys

    NASA Technical Reports Server (NTRS)

    Bray, G. H.; Reynolds, A. P.; Starke, E. A., Jr.

    1992-01-01

    In ingot metallurgy (IM) alloys, the number of delay cycles following a single tensile overload typically increases from a minimum at an intermediate baseline stress intensity range, Delta-K(B), with decreasing Delta-K(B) approaching threshold and increasing Delta-K(B) approaching unstable fracture to produce a characteristic 'U' shaped curve. Two models have been proposed to explain this behavior. One model is based on the interaction between roughness and plasticity-induced closure, while the other model only utilizes plasticity-induced closure. This article examines these models, using experimental results from constant amplitude and single overload fatigue tests performed on two powder metallurgy (PM) aluminum alloys, AL-905XL and AA 8009. The results indicate that the 'U'-shaped curve is primarily due to plasticity-induced closure, and that the plasticity-induced retardation effect is through-thickness in nature, occurring in both the surface and interior regions. However, the retardation effect is greater at the surface, because the increase in plastic strain at the crack tip and overload plastic zone size are larger in the plane-stress surface regions than in the plane-strain interior regions. These results are not entirely consistent with either of the proposed models.

  5. Development of an extra-high strength powder metallurgy nickel-base superalloy

    NASA Technical Reports Server (NTRS)

    Kent, W. B.

    1977-01-01

    A program was conducted to optimize the composition of NASA IIb-11, an alloy originally developed as a wrought material, for thermal stability and to determine the feasibility for producing the alloy using powder metallurgy techniques. Seven compositions were melted and atomized, hot isostatically pressed, cross rolled to disks and heat treated. Tensile and stress rupture properties from room temperature to 870 C (1600 F) were determined in addition to thermal stability characteristics. Processing variables included hot isostatic pressing parameters and handling, cross rolling procedures and heat treatment cycles. NASA IIb-11E displayed the best combination of overall properties for service as a 760 C (1400 F) disk material. Its composition is 0.06 C, 8.5 Cr, 9.0 Co, 2.0 Mo, 7.1 W, 6.6 Ta, 4.5 Al, 0.75 Ti, 0.5 V, 0.7 Hf, 0.01 B, 0.05 Zr and balance Ni. While the alloy exhibits the highest 760 C (1400 F) rupture strength reported for any powder metallurgy disk alloy to date, additional studies to further evaluate the effects of heat treatment may be required. The alloy is not susceptible to topologically close-packed phase formation during thermal exposure at 870 C (1600 F) for 1,500 hours, but its mechanical property levels are lowered due to grain boundary carbide formation.

  6. Comparison of the creep properties of cast and powder metallurgy-extruded binary NiAl

    SciTech Connect

    Raj, S.V.; Garg, A.; Bieler, T.R.

    1997-12-31

    The current emphasis in developing NiAl-based alloys for use in gas-turbine aircraft engines requires a fundamental understanding of the creep mechanisms dominant in these materials. Here, a comparison of published creep data on binary NiAl showed that there is a discrepancy in the reported magnitudes of the stress exponents, n, which usually vary between about 4.5 and 6.5. In general, a close examination of the data suggested that n {approx} 4.5 for cast materials and 6.5 for powder-metallurgy extruded NiAl. Constant load compression creep tests were conducted on a cast and extruded binary NiAl between 800 and 1,200 K over a wide range of initial applied stresses varying between 4.0 and 200 MPa. The microstructures were characterized by transmission electron microscopy. The observed variations in the creep behavior of the extruded cast and powder-metallurgy NiAl appeared to be due to a grain size effect. Despite similarities in the values of n, no significant substructure was observed in most of the grains in the cast and extruded specimens at 1,100 and 1,200 K in contrast to the PM-extruded alloy, which revealed a wide range of substructural features in the power-law creep region. However, extensive subgrain formation and dislocations were widely observed at lower temperatures and higher stresses in the cast and extruded material.

  7. Influence of Sintering under Nitrogen Atmosphere on Microstructures of Powder Metallurgy Duplex Stainless Steels

    NASA Astrophysics Data System (ADS)

    García, C.; Martin, F.; Blanco, Y.; de Tiedra, M. P.; Aparicio, M. L.

    2009-02-01

    Duplex stainless steels (SS) obtained through powder metallurgy (PM) from austenitic AISI 316L and ferritic AISI 430L powders were mixed in different amounts to obtain a biphasic structure with an austenite/ferrite ratio of 50/50, 65/35, and 85/15. Prepared powders were compacted at 750 MPa and sintered in N2-H2 (95 pct-5 pct) at 1250 °C for 1 hour. Some samples sintered in vacuum were taken as references. Optical metallography, X-ray diffraction, and scanning electron microscopy/energy dispersive analysis of X-rays were used for microstructural characterization. Powder metallurgy base materials, AISI 430L and 316L, showed a single lamellar constituent after sintering in nitrogen. A mixed constituent was identified in PM duplex SS sintered in nitrogen and in vacuum. However, coarse and fine lamellar constituents were only present in PM duplex SS sintered in nitrogen. The effects of annealing solution heat treatment (1150 °C) on microstructures were evaluated. Homogeneous structures were obtained for the PM base materials, while for PM duplex SS, annealing dissolved lamellar constituents but mixed constituent were still present.

  8. 26 CFR 509.106 - Control of a United States enterprise by a Swiss enterprise.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 19 2011-04-01 2010-04-01 true Control of a United States enterprise by a Swiss enterprise. 509.106 Section 509.106 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY... States enterprise by a Swiss enterprise. In effect, Article IV of the convention provides that, if...

  9. 26 CFR 509.106 - Control of a United States enterprise by a Swiss enterprise.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 19 2013-04-01 2010-04-01 true Control of a United States enterprise by a Swiss enterprise. 509.106 Section 509.106 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY... States enterprise by a Swiss enterprise. In effect, Article IV of the convention provides that, if...

  10. 26 CFR 509.106 - Control of a United States enterprise by a Swiss enterprise.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 19 2014-04-01 2010-04-01 true Control of a United States enterprise by a Swiss enterprise. 509.106 Section 509.106 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY... States enterprise by a Swiss enterprise. In effect, Article IV of the convention provides that, if...

  11. 26 CFR 509.106 - Control of a United States enterprise by a Swiss enterprise.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 19 2012-04-01 2010-04-01 true Control of a United States enterprise by a Swiss enterprise. 509.106 Section 509.106 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY... States enterprise by a Swiss enterprise. In effect, Article IV of the convention provides that, if...

  12. Enterprise 3.0 in Engineering Education

    ERIC Educational Resources Information Center

    Ahrens, Andreas; Zascerinska, Jelena

    2011-01-01

    Enterprise 3.0 offers potential solutions for the quality, maintenance and sustainable development of services. The synergy between Enterprise 3.0 and engineering education advances the development of innovative products, processes and services in the European economy. Aim of the research is to analyze student engineers' use of Enterprise 3.0…

  13. Do "Some" Enterprise Zones Create Jobs?

    ERIC Educational Resources Information Center

    Kolko, Jed; Neumark, David

    2010-01-01

    We study how the employment effects of enterprise zones vary with their location, implementation, and administration, based on evidence from California. We use new establishment-level data and geographic mapping methods, coupled with a survey of enterprise zone administrators. Overall, the evidence indicates that enterprise zones do not increase…

  14. The Adaptability Evaluation of Enterprise Information Systems

    NASA Astrophysics Data System (ADS)

    Liu, Junjuan; Xue, Chaogai; Dong, Lili

    In this paper, a set of evaluation system is proposed by GQM (Goal-Question-Metrics) for enterprise information systems. Then based on Similarity to Ideal Solution (TOPSIS), the evaluation model is proposed to evaluate enterprise information systems' adaptability. Finally, the application of the evaluation system and model is proved via a case study, which provides references for optimizing enterprise information systems' adaptability.

  15. Technical Education in the Enterprise Zone.

    ERIC Educational Resources Information Center

    Friedman, Howard

    Support is growing for the concept of the enterprise zone. Congress has before it a bill, the Enterprise Zone Tax Act of 1982, that would provide incentives and create a climate in which entrepreneurs and business executives would locate businesses in areas of pervasive poverty and unemployment. A potential urban enterprise zone in New York City…

  16. Animal Enterprise Record Book. Agricultural Education.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Agricultural Curriculum Materials Service.

    This record book is intended for use by agricultural education students who have ownership arrangements in animal enterprise experience programs. A major purpose of this book is to aid in separating out or allocating the costs and returns to a specific enterprise. The financial, labor, and management aspects of each enterprise can then be studied…

  17. Evaluating Enterprise Education: Why Do It?

    ERIC Educational Resources Information Center

    Edwards, Louise-Jayne; Muir, Elizabeth J.

    2012-01-01

    Purpose: The purpose of this paper is to argue that evaluations of enterprise education need to develop beyond the economist viewpoint of business start-up and business growth and promote the notion that evaluations of enterprise education should encompass prime pedagogical objectives of enterprise education, enabling students to grow and develop…

  18. Advances in powder metallurgy - 1991. Vol. 6 - Aerospace, refractory and advanced materials; Proceedings of the Powder Metallurgy Conference and Exhibition, Chicago, IL, June 9-12, 1991

    SciTech Connect

    Pease, L.F. III; Sansoucy, R.J.

    1991-01-01

    Various papers on aerospace, refractory, and advanced materials are presented. Individual topics addressed include: nonequilibrium processing of powder alloys for aerospace applications, chemical conditioning of rapidly solidified aluminum alloy particulate, fabrication of rapidly solidified high temperature aluminum alloys, fatigue and fracture of an advanced PM-aluminum alloy, thermal and mechanical properties of extruded 7075-Al P/M alloys, reactive sintering and reactive hot isostatic pressing of iron aluminides, P/M processing and applications of Fe3Al-based intermetallics, properties of plasma atomized NiAl powders, processing of continuous fiber reinforced NiAl matrix composite. Also discussed are: powder forging process on an alumimum alloy, P/M magnesium particle composites, P/M short-fiber-reinforced magnesium, mechanical properties of a TiAl6V4 alloy processed by powder metallurgy, porous core/Be Ti-6-4 development for aerospace structures, consolidation and plasticity of Bi-Sr-Ca-Cu-O superconductors, development of a new W-Ni-Mn heavy alloy.

  19. Self-Paced Tutorial Courses for Mineral Science - Metallurgy Departments. Final Progress Report (July 1975-August 1980).

    ERIC Educational Resources Information Center

    Twidwell, L. G.

    Four courses in extractive metallurgy (Pyrometallurgy, Hydrometallurgy, Electrometallurgy; and Physical Chemistry of Iron and Steel) were prepared in a modular, self-paced format. Development of the course materials included: (1) preparation of course outlines by unit coordinators and advisory committees; (2) approval of course outlines (included…

  20. Designing normative open virtual enterprises

    NASA Astrophysics Data System (ADS)

    Garcia, Emilia; Giret, Adriana; Botti, Vicente

    2016-03-01

    There is an increasing interest on developing virtual enterprises in order to deal with the globalisation of the economy, the rapid growth of information technologies and the increase of competitiveness. In this paper we deal with the development of normative open virtual enterprises (NOVEs). They are systems with a global objective that are composed of a set of heterogeneous entities and enterprises that exchange services following a specific normative context. In order to analyse and design systems of this kind the multi-agent paradigm seems suitable because it offers a specific solution for supporting the social and contractual relationships between enterprises and for formalising their business processes. This paper presents how the Regulated Open Multi-agent systems (ROMAS) methodology, an agent-oriented software methodology, can be used to analyse and design NOVEs. ROMAS offers a complete development process that allows identifying and formalising of the structure of NOVEs, their normative context and the interactions among their members. The use of ROMAS is exemplified by means of a case study that represents an automotive supply chain.

  1. Value Modeling for Enterprise Resilience

    SciTech Connect

    Henderson, Dale L.; Lancaster, Mary J.

    2015-10-20

    Abstract. The idea that resilience is a tangible, measureable, and desirable system attribute has grown rapidly over the last decade beyond is origins in explaining ecological, physiological, psychological, and social systems. Operational enterprise resilience requires two types of measurement. First, the system must monitor various operational conditions in order to respond to disruptions. These measurements are part of one or more observation, orientation, decision, and action (OODA) loops The OODA control processes that implement a resilience strategy use these measurements to provide robustness, rapid recovery and reconstitution. In order to assess the effectiveness of the resilience strategy, a different class of measurements is necessary. This second type consists of measurements about how well the OODA processes cover critical enterprise functions and the hazards to which the enterprise is exposed. They allow assessment of how well enterprise management processes anticipate, mitigate, and adapt to a changing environment and the degree to which the system is fault tolerant. This paper nominates a theoretical framework, in the form of definitions, a model, and a syntax, that accounts for this important distinction, and in so doing provides a mechanism for bridging resilience management process models and the many proposed cyber-defense metric enumerations.

  2. Governance Failure in Social Enterprise

    ERIC Educational Resources Information Center

    Low, Chris; Chinnock, Chris

    2008-01-01

    This article aims to evaluate the effectiveness of the participative, democratic model of governance commonly found within social enterprises. This model has its origins in the broader not-for-profit sector where it is widely adopted. A core assumption of this governance form is that it ensures that the organisation will take a range of views into…

  3. Ethics, Governance, Research and Enterprise

    ERIC Educational Resources Information Center

    Lategan, Laetus; Hooper, Peter

    2009-01-01

    The focus of this paper is to reflect on research ethics practices at universities and particularly on the additional considerations needed as "enterprise" becomes a key driver across the sector internationally. The outcome of the paper is to identify suitable guidelines for dealing with the management of research ethics in this changing…

  4. Obstacles to Financing Minority Enterprises.

    ERIC Educational Resources Information Center

    District of Columbia Advisory Committee to the United States Commission on Civil Rights.

    In 1972, the District of Columbia Advisory Committee initiated an inquiry to determine the role that discrimination has played in limiting minority business enterprises in the Washington area. Meetings were held in which businessmen, representatives of technical assistance organizations, government officials, and bankers examined the question of…

  5. The Enterprise of the Future

    ERIC Educational Resources Information Center

    Murray, Dennis J.

    2009-01-01

    Last year, IBM Corporation conducted a study to determine what the successful enterprise of the future would look like. Its research was based on surveys of 1,130 CEOs, general managers, and senior public sector and business leaders from around the world. A few college and university presidents also were asked to participate. After 30 years as a…

  6. PPEPR for Enterprise Healthcare Integration

    NASA Astrophysics Data System (ADS)

    Fox, Ronan; Sahay, Ratnesh; Hauswirth, Manfred

    PPEPR is software to connect healthcare enterprises. Healthcare is a complex domain and any integration system that connects healthcare enterprise applications must facilitate heterogeneous healthcare systems at all levels - data, services, processes, healthcare vendors, standards, legacy systems, and new information systems, all of which must interoperate to provide healthcare services. The lack of interoperability within healthcare standards (e.g. HL7) adds complexity to the interoperability initiatives. HL7’s user base has been growing since the early 2000s. There are many interoperability issues between the widely adopted HL7 v2 and its successor, HL7 v3, in terms of consistency, data/message modeling, precision, and useability. We have proposed an integration platform called PPEPR: (Plug and Play Electronic Patient Records) which is based on a semantic Service-oriented Architecture (sSOA). PPEPR connects HL7 (v2 & v3) compliant healthcare enterprises. Our main goal is to provide seamless integration between healthcare enterprises without imposing any constraint on existing or proposed EPRs.

  7. INTEGRATED TAXONOMIC INFORMATION SYSTEM (ITIS) - BACILLARIOPHYTA

    EPA Science Inventory

    Access to consistent, scientifically credible taxomonic information is essential to many governmental activities. These activities include natural resource management for sustained use, land owner assistance, environmental regulation, and biotechnology development. As part of the...

  8. Gametogenesis and Auxospore Development in Actinocyclus (Bacillariophyta)

    PubMed Central

    Idei, Masahiko; Osada, Keigo; Sato, Shinya; Toyoda, Kensuke; Nagumo, Tamotsu; Mann, David G.

    2012-01-01

    cGametogenesis and auxospore development have been studied in detail in surprisingly few centric diatoms. We studied the development of sperm, eggs and auxospores in Actinocyclus sp., a radially symmetrical freshwater diatom collected from Japan, using LM and electron microscopy of living cultures and thin sections. Actinocyclus represents a deep branch of the ‘radial centric’ diatoms and should therefore contribute useful insights into the evolution of sexual reproduction in diatoms. Spermatogenesis was examined by LM and SEM and involved the formation of two spermatogonia (sperm mother-cells) in each spermatogonangium through an equal mitotic division. The spermatogonia produced a reduced ‘lid’ valve, resembling a large flat scale with irregular radial thickenings. Sperm formation was merogenous, producing four sperm per spermatogonium, which were released by dehiscence of the ‘lid’ valve. The sperm were spindle-shaped with numerous surface globules and, as usual for diatoms, the single anterior flagellum bore mastigonemes. One egg cell was produced per oogonium. Immature eggs produced a thin layer of circular silica scales before fertilization, while the eggs were still contained within the oogonium. Sperm were attracted in large numbers to each egg and were apparently able to contact the egg surface via a gap formed between the long hypotheca and shorter epitheca of the oogonium and a small underlying hole in the scale-case. Auxospores expanded isodiametrically and many new scales were added to its envelope during expansion. Finally, new slightly-domed initial valves were produced at right angles to the oogonium axis, after a strong contraction of the cell away from the auxospore wall. At different stages, Golgi bodies were associated with chloroplasts or mitochondria, contrasting with the constancy of Golgi–ER–mitochondrion (G-ER-M) units in some other centric diatoms, which has been suggested to have phylogenetic significance. Electron-dense bodies in the vacuole of Actinocyclus are probably acidocalcisomes containing polyphosphate. PMID:22870259

  9. Causal Factors of Weld Porosity in Gas Tungsten Arc Welding of Powder Metallurgy Produced Titanium Alloys

    SciTech Connect

    Muth, Thomas R; Yamamoto, Yukinori; Frederick, David Alan; Contescu, Cristian I; Chen, Wei; Lim, Yong Chae; Peter, William H; Feng, Zhili

    2013-01-01

    ORNL undertook an investigation using gas tungsten arc (GTA) welding on consolidated powder metallurgy (PM) titanium (Ti) plate, to identify the causal factors behind observed porosity in fusion welding. Tramp element compounds of sodium and magnesium, residual from the metallothermic reduction of titanium chloride used to produce the titanium, were remnant in the starting powder and were identified as gas forming species. PM-titanium made from revert scrap where sodium and magnesium were absent, showed fusion weld porosity, although to a lesser degree. We show that porosity was attributable to hydrogen from adsorbed water on the surface of the powders prior to consolidation. The removal / minimization of both adsorbed water on the surface of titanium powder and the residues from the reduction process prior to consolidation of titanium powders, are critical to achieve equivalent fusion welding success similar to that seen in wrought titanium produced via the Kroll process.

  10. Crack Formation in Powder Metallurgy Carbon Nanotube (CNT)/Al Composites During Post Heat-Treatment

    NASA Astrophysics Data System (ADS)

    Chen, Biao; Imai, Hisashi; Li, Shufeng; Jia, Lei; Umeda, Junko; Kondoh, Katsuyoshi

    2015-12-01

    After the post heat-treatment (PHT) process of powder metallurgy carbon nanotubes (CNT)/Al composites, micro-cracks were observed in the composites, leading to greatly degraded mechanical properties. To understand and suppress the crack formation, an in situ observation of CNT/Al composites was performed at elevated temperatures. PHT was also applied to various bulk pure Al and CNT/Al composites fabricated under different processes. It was observed that the composites consolidated by hot-extrusion might form micro-cracks, but those consolidated by spark plasma sintering (SPS) showed no crack after PHT. A high-temperature SPS process before hot-extrusion was effective to prevent crack formation. The release of residual stress in severe plastic deformed (SPD) materials was responsible for the cracking phenomena during the PHT process. Furthermore, a good particle bonding was essential and effective to suppress cracks for SPD materials in the PHT process.

  11. Physical and mechanical metallurgy of high purity Nb for accelerator cavities

    SciTech Connect

    Bieler, T. R.; Wright, N. T.; Pourboghrat, F.; Compton, C.; Hartwig, K. T.; Baars, D.; Zamiri, A.; Chandrasekaran, S.; Darbandi, P.; Jiang, H.; Skoug, E.; Balachandran, S.; Ice, Gene E; Liu, W.

    2010-01-01

    In the past decade, high Q values have been achieved in high purity Nb superconducting radio frequency (SRF) cavities. Fundamental understanding of the physical metallurgy of Nb that enables these achievements is beginning to reveal what challenges remain to establish reproducible and cost-effective production of high performance SRF cavities. Recent studies of dislocation substructure development and effects of recrystallization arising from welding and heat treatments and their correlations with cavity performance are considered. With better fundamental understanding of the effects of dislocation substructure evolution and recrystallization on electron and phonon conduction, as well as the interior and surface states, it will be possible to design optimal processing paths for cost-effective performance using approaches such as hydroforming, which minimizes or eliminates welds in a cavity.

  12. Corrosion Resistance of Powder Metallurgy Processed TiC/316L Composites with Mo Additions

    NASA Astrophysics Data System (ADS)

    Lin, Shaojiang; Xiong, Weihao

    2015-06-01

    To find out the effects of Mo addition on corrosion resistance of TiC/316L stainless steel composites, TiC/316L composites with addition of different contents of Mo were prepared by powder metallurgy. The corrosion resistance of these composites was evaluated by the immersion tests and polarization curves experiments. Results indicated that Mo addition decreased the corrosion rates of TiC/316L composites in H2SO4 solution in the case of Mo content below 2% whereas it displayed an opposite effect when Mo content was above that value. It was found that with an increase in the Mo content, the pitting corrosion resistance increased monotonically for TiC/316L composites in NaCl solution.

  13. Mechanical cycling effects at Fe-Mn-Si-Cr-Ni SMAs obtained by powder metallurgy

    NASA Astrophysics Data System (ADS)

    Pricop, B.; Söyler, U.; Comčneci, R. I.; Özkal, B.; Bujoreanu, L. G.

    Specimens from Fe-Mn-Si-Cr-Ni SMA, obtained by powder metallurgy and compacted through hot rolling, were subjected to tensile loading-unloading cycles. The pseudoelastic parameters were determined based on recorded stress-strain curves, and their variation tendency with increasing the number of mechanical cycles was discussed. The gauges of tensile specimens were cut after mechanical cycling and were subjected to structural and dilatometric analysis. The structure was analyzed by XRD and SEM, aiming to reveal mechanical cycling effects. The thermomechanical response on heating, of mechanically cycled specimens, was recorded by dilatometry and revealed a tendency to enhance thermal expansion as an effect of increasing the number of cycles. The microstructural changes, induced by mechanical cycling, consisted in the stress induced formation of α' martensite.

  14. Effects of fine porosity on the fatigue behavior of a powder metallurgy superalloy

    NASA Technical Reports Server (NTRS)

    Miner, R. V., Jr.; Dreshfield, R. L.

    1980-01-01

    Hot isostatically pressed powder metallurgy Astroloy was obtained which contained 1.4 percent fine porosity at the grain boundaries produced by argon entering the powder container during pressing. This material was tested at 650 C in fatigue, creep fatigue, tension, and stress-rupture and the results compared with previous data on sound Astroloy. The pores averaged about 2 micrometers diameter and 20 micrometers spacing. They did influence fatigue crack initiation and produced a more intergranular mode of propagation. However, fatigue life was not drastically reduced. A large 25 micrometers pore in one specimen resulting from a hollow particle did not reduce life by 60 percent. Fatigue behavior of the porous material showed typical correlation with tensile behavior. The plastic strain range life relation was reduced proportionately with the reduction in tensile ductility, but the elastic strain range-life relation was little changed reflecting the small reduction in sigma sub u/E for the porous material.

  15. Effect of glow discharge sintering in the properties of a composite material fabricated by powder metallurgy

    NASA Astrophysics Data System (ADS)

    Cardenas, A.; Pineda, Y.; Sarmiento Santos, A.; Vera, E.

    2016-02-01

    Composite samples of 316 stainless steel and SiC were produced by powder metallurgy. Starting materials were mixed in different proportions and compacted to 700MPa. Sintering stage was performed by abnormal glow discharge plasma with direct current in an inert atmosphere of argon. The process was conducted at a temperature of 1200°C±5°C with a heating rate of 100°C/min. This work shows, the effectiveness of plasma sintering process to generate the first contacts between particles and to reduce vacancies. This fact is confirmed by comparing green and sintered density of the material. The results of porosity show a decrease after plasma sintering. Wear tests showed the wear mechanisms, noting that at higher SiC contents, the wear resistance decreases due to poor matrix-reinforcement interaction and by the porosity presence which causes matrix-reinforcement sliding.

  16. Effects of fine porosity on the fatigue behavior of a powder metallurgy superalloy

    NASA Technical Reports Server (NTRS)

    Miner, R. V.; Dreshfield, R. L.

    1980-01-01

    Hot-isostatically-pressed powder-metallurgy Astroloy was obtained which contained 1.4 percent porosity at the grain boundaries produced by argon entering the powder container during pressing. This material was tested at 650 C in fatigue, creep-fatigue, tension, and stress-rupture and the results compared with data on sound Astroloy. They influenced fatigue crack initiation and produced a more intergranular mode of propagation but fatigue life was not drastically reduced. Fatigue behavior of the porous material showed typical correlation with tensile behavior. The plastic strain range-life relation was reduced proportionately with the reduction in tensile ductility, but the elastic strain range-life relation was changed little.

  17. Studies on ancient silver metallurgy using SR XRF and micro-PIXE

    NASA Astrophysics Data System (ADS)

    Vasilescu, Angela; Constantinescu, Bogdan; Stan, Daniela; Radtke, Martin; Reinholz, Uwe; Buzanich, Guenter; Ceccato, Daniele

    2015-12-01

    This work presents a complex evaluation of a series of Geto-Thracian silver adornments found on Romanian territory, part of the 4th century BC Agighiol (Northern Dobruja) hoard and of an ingot from the 1st century BC Geto-Dacian Surcea (Transylvania) hoard, using Synchrotron Radiation X-Ray Fluorescence and micro- Proton Induced X-ray Emission analysis and mapping in order to investigate aspects related to the elemental composition of the metal and the metallurgy implied in their manufacture. One of the samples can be linked to Laurion as the source of metal, and several items contain silver probably originated in Macedonia. The set of silver items was found to be heteregenous as composition and microstructure, and corrosion-related elements could be also identified in the X-Ray maps.

  18. Abnormal magnetic behaviour of powder metallurgy austenitic stainless steels sintered in nitrogen

    NASA Astrophysics Data System (ADS)

    García, C.; Martin, F.; Blanco, Y.

    2009-10-01

    The magnetic response of AISI 304L and AISI 316L obtained through powder metallurgy and sintered in nitrogen were studied. AISI 304L sintered in nitrogen showed a ferromagnetic behaviour in as-sintered state while AISI 316L was paramagnetic. After solution annealing both were paramagnetic. Magnetic behaviour was analysed by using a vibrating sample magnetometer, a magnetic ferritscope and magnetic etching. A microstructural characterization was performed by means of optical metallography, X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive analysis of X-rays (EDS). Some samples when needed were submitted to aged heat treatments at 675 and 875 °C for 90 min, 4, 6, 8 or 48 h. The main microstructural feature found was the presence of a lamellar constituent formed by nitride precipitates and an interlamellar matrix of austenite and/or ferrite. The abnormal magnetic response was explained based on this.

  19. Accelerated Threshold Fatigue Crack Growth Effect-Powder Metallurgy Aluminum Alloy

    NASA Technical Reports Server (NTRS)

    Piascik, R. S.; Newman, J. A.

    2002-01-01

    Fatigue crack growth (FCG) research conducted in the near threshold regime has identified a room temperature creep crack growth damage mechanism for a fine grain powder metallurgy (PM) aluminum alloy (8009). At very low (Delta) K, an abrupt acceleration in room temperature FCG rate occurs at high stress ratio (R = K(sub min)/K(sub max)). The near threshold accelerated FCG rates are exacerbated by increased levels of K(sub max) (K(sub max) = 0.4 K(sub IC)). Detailed fractographic analysis correlates accelerated FCG with the formation of crack-tip process zone micro-void damage. Experimental results show that the near threshold and K(sub max) influenced accelerated crack growth is time and temperature dependent.

  20. The alloy with a memory, 55-Nitinol: Its physical metallurgy, properties, and applications

    NASA Technical Reports Server (NTRS)

    Jackson, C. M.; Wagner, H. J.; Wasilewski, R. J.

    1972-01-01

    A series of nickel titanium alloys (55-Nitinol), which are unique in that they possess a shape memory, are described. Components made of these materials that are altered in their shapes by deformation under proper conditions return to predetermined shapes when they are heated to the proper temperature range. The shape memory, together with the force exerted and the ability of the material to do mechanical work as it returns to its predetermined shape, suggest a wide variety of industrial applications for the alloy. Also included are discussions of the physical metallurgy and the mechanical, physical, and chemical properties of 55-Nitinol; procedures for melting and processing the material into useful shapes; and a summary of applications.

  1. Microstructure and mechanical properties of P/M (powder metallurgy) Fe sub 3 Al alloys

    SciTech Connect

    Knibloe, J.R.; Wright, R.N. ); Sikka, V.K. )

    1990-01-01

    Alloys based on Fe{sub 3}Al have an equilibrium DO{sub 3} structure at low temperatures and transform to a B2 structure above about 550{degree}C. The influence of different rates of quenching from the B2 region to room temperature on the microstructure and mechanical properties of powder metallurgy (P/M) alloys with two different Cr contents has been examined. By optimizing the processing to maximize the amount of B2 order, room temperature ductility approaching 20% has been achieved although the fracture mode is primarily brittle cleavage. The refined microstructure resulting from P/M processing contributes to enhanced yield strength compared to ingot processed materials with similar ductility. Increasing the Cr content from 2 to 5% has little effect on mechanical properties. 8 refs., 12 figs., 2 tabs.

  2. Emission of PCDD/Fs and dioxin-like PCBs from metallurgy industries in S. Korea.

    PubMed

    Yu, Byeong-Woon; Jin, Guang-Zhu; Moon, Young-Hoon; Kim, Min-Kwan; Kyoung, Jong-Dai; Chang, Yoon-Seok

    2006-01-01

    The metallurgy industry and municipal waste incinerators are considered the main sources of polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) in many countries. This study investigated the emission factors and total emissions of PCDD/Fs and dioxin-like polychlorinated biphenyls (PCBs) emitted from metallurgy industries (including ferrous and nonferrous foundries) in Korea. The toxic equivalency (TEQ) emission factor of PCDD/Fs was the highest for secondary copper production, at 24451 ng I-TEQ/ton. The total estimated emissions of PCDD/Fs from these sources were 35.259 g I-TEQ/yr, comprising 0.088 g I-TEQ/yr from ferrous foundries, 31.713 g I-TEQ/yr from copper production, 1.716 g I-TEQ/yr from lead production, 0.111 g I-TEQ/yr from zinc production, and 1.631 g I-TEQ/yr from aluminum production. The total estimated annual amounts of dioxin-like PCBs emitted from these sources were 13.260 g WHO-TEQ/yr, comprising 0.014 g WHO-TEQ/yr from ferrous foundries, 12.675 g WHO-TEQ/yr from copper production, 0.170 g WHO-TEQ/yr from lead production, 0.017 g WHO-TEQ/yr from zinc production, and 0.384 g WHO-TEQ/yr from aluminum production. The highest emission factor was found for secondary copper smelting, at 9770 ng WHO-TEQ/ton. PMID:15939459

  3. Assessment of Low Cycle Fatigue Behavior of Powder Metallurgy Alloy U720

    NASA Technical Reports Server (NTRS)

    Gabb, Tomothy P.; Bonacuse, Peter J.; Ghosn, Louis J.; Sweeney, Joseph W.; Chatterjee, Amit; Green, Kenneth A.

    2000-01-01

    The fatigue lives of modem powder metallurgy disk alloys are influenced by variabilities in alloy microstructure and mechanical properties. These properties can vary as functions of variables the different steps of materials/component processing: powder atomization, consolidation, extrusion, forging, heat treating, and machining. It is important to understand the relationship between the statistical variations in life and these variables, as well as the change in life distribution due to changes in fatigue loading conditions. The objective of this study was to investigate these relationships in a nickel-base disk superalloy, U720, produced using powder metallurgy processing. Multiple strain-controlled fatigue tests were performed at 538 C (1000 F) at limited sets of test conditions. Analyses were performed to: (1) assess variations of microstructure, mechanical properties, and LCF failure initiation sites as functions of disk processing and loading conditions; and (2) compare mean and minimum fatigue life predictions using different approaches for modeling the data from assorted test conditions. Significant variations in life were observed as functions of the disk processing variables evaluated. However, the lives of all specimens could still be combined and modeled together. The failure initiation sites for tests performed at a strain ratio R(sub epsilon) = epsilon(sub min)/epsilon(sub max) of 0 were different from those in tests at a strain ratio of -1. An approach could still be applied to account for the differences in mean and maximum stresses and strains. This allowed the data in tests of various conditions to be combined for more robust statistical estimates of mean and minimum lives.

  4. Analysis of Enterprise Workflow Solutions

    NASA Astrophysics Data System (ADS)

    Chen, Cui-E.; Wang, Shulin; Chen, Ying; Meng, Yang; Ma, Hua

    Since the 90’s, workflow technology has been widely applied in various industries, such as office automation(OA), manufacturing, telecommunications services, banking, securities, insurance and other financial services, research institutes and education services, and so on, to improve business process automation and integration capabilities. In this paper, based on Workflow theory, the author proposed a set of policy-based workflow approach in order to support dynamic workflow patterns. Through the expansion of the functions of Shark, it implemented a Workflow engine component-OAShark which can support retrieval / rollback function. The related classes were programmed. The technology was applied to the OA system of an enterprise project. The realization of the enterprise workflow solutions greatly improved the efficiency of the office automation.

  5. Infrastructure for distributed enterprise simulation

    SciTech Connect

    Johnson, M.M.; Yoshimura, A.S.; Goldsby, M.E.

    1998-01-01

    Traditional discrete-event simulations employ an inherently sequential algorithm and are run on a single computer. However, the demands of many real-world problems exceed the capabilities of sequential simulation systems. Often the capacity of a computer`s primary memory limits the size of the models that can be handled, and in some cases parallel execution on multiple processors could significantly reduce the simulation time. This paper describes the development of an Infrastructure for Distributed Enterprise Simulation (IDES) - a large-scale portable parallel simulation framework developed to support Sandia National Laboratories` mission in stockpile stewardship. IDES is based on the Breathing-Time-Buckets synchronization protocol, and maps a message-based model of distributed computing onto an object-oriented programming model. IDES is portable across heterogeneous computing architectures, including single-processor systems, networks of workstations and multi-processor computers with shared or distributed memory. The system provides a simple and sufficient application programming interface that can be used by scientists to quickly model large-scale, complex enterprise systems. In the background and without involving the user, IDES is capable of making dynamic use of idle processing power available throughout the enterprise network. 16 refs., 14 figs.

  6. Haise Commands First Enterprise Test Flights

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The first crew members for the Space Shuttle Approach and Landing Tests (ALT) are photographed at the Rockwell International Space Division's Orbiter Assembly Facility at Palmdale, California. The Shuttle Enterprise is Commanded by former Apollo 13 Lunar Module pilot, Fred Haise (left) with C. Gordon Fullerton as pilot. The Shuttle Orbiter Enterprise was named after the fictional Starship Enterprise from the popular 1960's television series, Star Trek.

  7. Bio-mimetic scaling of mechanical behavior of thin films, coatings, and surfaces by Laser Interference Metallurgy

    SciTech Connect

    Daniel, Claus; Balk, Thomas John; Wobben, Thomas; M�cklich, Frank

    2005-01-01

    Biological solutions to enhance strength and stability often use hierarchical composite structures. The effect is not based on large chemical variations, but instead is realized by structural composites with long-range order. Laser Interference Metallurgy is a newly developed technique that utilizes this biological approach to optimize the mechanical properties of surfaces and thin films. The possibility of scaling mechanical properties is quantitatively analyzed and compared with the biological approach.

  8. The Impact of Enterprise Education on Attitudes to Enterprise in Young People: An Evaluation Study

    ERIC Educational Resources Information Center

    Athayde, Rosemary

    2012-01-01

    Purpose: The purpose of the paper is to present evidence on the impact of enterprise education on young people still at school in London, UK. The study was designed to measure the effect of participation in a Young Enterprise (YE) Company Program on young people's attitudes toward starting a business, and on their enterprise potential.…

  9. 26 CFR 509.106 - Control of a United States enterprise by a Swiss enterprise.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 19 2010-04-01 2010-04-01 false Control of a United States enterprise by a Swiss enterprise. 509.106 Section 509.106 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) REGULATIONS UNDER TAX CONVENTIONS SWITZERLAND General Income Tax § 509.106 Control of a United States enterprise by a...

  10. Analysis of Load Transfer Mechanism in Cu Reinforced with Carbon Nanotubes Fabricated by Powder Metallurgy Route

    NASA Astrophysics Data System (ADS)

    Akbarpour, Mohammad Reza

    2016-04-01

    Abstract: In this research, ductile and high-strength Cu-carbon nanotube (Cu-CNT) composites with different volume fractions of CNTs were fabricated using powder metallurgy route including mechanical milling and hot pressing and microstructure and tensile properties of the resulting materials were studied. Microstructural characterization through scanning electron microscope and quantifying the CNT agglomeration revealed that uniform dispersion of CNTs in Cu matrix decreases with increasing CNT volume fraction. In case of the higher volume fraction of CNTs (i.e., 8 vol.%), ~ 40% of CNTs were observed as agglomerates in the microstructure. Compared to unreinforced Cu, the yield and ultimate tensile strengths increased considerably (about 33% and 12%, respectively) with incorporation of CNTs up to 4 vol.%, but remained constant afterward. Meanwhile, the elongation decreased from 15.6% for Cu to 6.9% for Cu with 8 vol.% CNT. The relationship between the change in yield strength of the composite and the microstructure was investigated using analytical models. The results showed good consistency between calculated and measured data when the negative effect of CNT agglomerates in the models were taken into account.

  11. Laser Interference Metallurgy - using interference as a tool for micro/nano structuring

    SciTech Connect

    M�cklich, Frank; Lasagni, Andres Fabian; Daniel, Claus

    2006-01-01

    Interfering laser beams of a high-power pulsed laser provide the opportunity of applying a direct lateral interaction with the surface microstructure of metals in micro/nanoscale based on photo-thermal nature mechanisms. This "Laser interference metallurgy" allows the creation of periodic patterns of features with a well defined long-range order on metallic surfaces at the scale of typical microstructures (from the sub micrometer level up to micrometers). This technique is an approach to initiate metallurgical processes such as melting, recrystallization, recovery, and defect and phase formation in the lateral scale of the microstructure itself and with an additional long range order given by the interference periodicity. In this work, the laser interference theory is described and used to calculate multi-beam interference patterns. A method to calculate the numbers of laser beams as well as the geometrical arrangement of the beams to obtain a desired periodical pattern prior to experiments is presented. The formation of long-range-ordered intermetallic compounds as well as macroscopic and microscopic variations of mechanical properties on structured metallic thin films are presented as examples.

  12. Tribological Properties of the Fe-Al-Cr Alloyed Layer by Double Glow Plasma Surface Metallurgy

    NASA Astrophysics Data System (ADS)

    Luo, Xixi; Yao, Zhengjun; Zhang, Pingze; Zhou, Keyin; Wang, Zhangzhong

    2016-07-01

    A Fe-Al-Cr alloyed layer was deposited onto the surface of Q235 low-carbon steel via double glow plasma surface metallurgy (DGPSM) to improve the steel's wear resistance. After the DGPSM treatment, the Fe-Al-Cr alloyed layer grown on the Q235 low-carbon steel was homogeneous and compact and had a thickness of 25 µm. The layer was found to be metallurgically adhered to the substrate. The frictional coefficient and specific wear rate of the sample with a Fe-Al-Cr alloyed layer (treated sample) were both lower than those of the bare substrate (untreated sample) at the measured temperatures (25, 250 and 450 °C). The results indicated that the substrate and the alloyed layer suffered oxidative wear and abrasive wear, respectively, and that the treated samples exhibited much better tribological properties than did the substrate. The formation of Fe2AlCr, Fe3Al(Cr), FeAl(Cr), Fe(Cr) sosoloid and Cr23C6 phases in the alloyed layer dramatically enhanced the wear resistance of the treated sample. In addition, the alloyed layer's oxidation film exhibited a self-healing capacity with lubrication action that also contributed to the improvement of the wear resistance at high temperature. In particular, at 450 °C, the specific wear rate of treated sample was 2.524 × 10-4 mm3/N m, which was only 45.2% of the untreated sample.

  13. Effect of porosity on the thermal conductivity of copper processed by powder metallurgy

    NASA Astrophysics Data System (ADS)

    Vincent, C.; Silvain, J. F.; Heintz, J. M.; Chandra, N.

    2012-03-01

    Powder metallurgy is a preferred method of processing copper-carbon composites due to the non-wetting nature of these materials. Porosities are inherently introduced in these material systems, and adversely affect the thermal conductivity of the composite material, among other factors including interfaces and reinforcement distribution. In this work, we focus on the matrix material of pure copper and systematically analyzed the effect of volume fraction of porosities on the thermal conductivity. Spherical and dendritic copper powder materials were processed and it was found that the surface chemistry and morphology of particles affected the thermal conductivity apart from the porosity values. In order to study the effect of porosities alone, dentritic powder was used in the study. The thermal conductivity vs. porosity behavior showed three distinct domains. In all the domains the thermal conductivity decreases as volume fraction of porosities increases; however, in domain II, the decrease was much steeper than the other two. We are able to explain the variation based on the presence of interconnected and open pores in domain III to closed pores in domain I, and the transition occurring in domain II. None of the existing models capture the overall behavior. However, if we specifically account for the variation of number of grain boundaries with sintering, then the modified EMT model can match the experimental data.

  14. Study of Metallic Carbide (MC) in a Ni-Co-Cr-Based Powder Metallurgy Superalloy

    NASA Astrophysics Data System (ADS)

    Ma, Wen-Bin; Liu, Guo-Quan; Hu, Ben-Fu; Hu, Peng-Hui; Zhang, Yi-Wen

    2014-01-01

    The evolution of carbides in a Ni-Cr-Co-based powder metallurgy (PM) superalloy in the as-atomized, as-atomized + annealed, hot isostatic pressed (HIPed) and HIPed + annealed conditions were systematically analyzed to understand the formation of blocky metallic carbide (MC) along the previous particle boundary (PPB). The results show that the carbides both on the powder surfaces and in the bulk of the powder particles are mainly fan-shaped MC whose decomposition temperatures are in the range of 1473 K to 1493 K (1200 °C to 1220 °C). PPB carbides in the HIPed alloy are mainly block-shaped MC, and the fan-shaped MC densely distributed in the area that have not been consumed by the recrystallized grains. The formation mechanism of PPB carbides can be described as follows: When the powders are HIPed at 1453 K (1180 °C), the fan-shaped carbides are decomposed at the migrating boundaries of recrystallized grains, and the preferential precipitation of block-shaped MC at PPB is promoted by the carbide-forming elements released by the fan-shaped carbides. When the HIPed alloy is annealed at 1453 K (1180 °C), the area fraction of PPB carbides increases with an increase in annealing time but that of the fan-shaped carbides exhibits opposite behavior. This proves the above formation mechanism of PPB carbides.

  15. A Novel Ni-Containing Powder Metallurgy Steel with Ultrahigh Impact, Fatigue, and Tensile Properties

    NASA Astrophysics Data System (ADS)

    Wu, Ming-Wei; Shu, Guo-Jiun; Chang, Shih-Ying; Lin, Bing-Hao

    2014-08-01

    The impact toughness of powder metallurgy (PM) steel is typically inferior, and it is further impaired when the microstructure is strengthened. To formulate a versatile PM steel with superior impact, fatigue, and tensile properties, the influences of various microstructures, including ferrite, pearlite, bainite, and Ni-rich areas, were identified. The correlations between impact toughness with other mechanical properties were also studied. The results demonstrated that ferrite provides more resistance to impact loading than Ni-rich martensite, followed by bainite and pearlite. However, Ni-rich martensite presents the highest transverse rupture strength (TRS), fatigue strength, tensile strength, and hardness, followed by bainite, pearlite, and ferrite. With 74 pct Ni-rich martensite and 14 pct bainite, Fe-3Cr-0.5Mo-4Ni-0.5C steel achieves the optimal combination of impact energy (39 J), TRS (2170 MPa), bending fatigue strength at 2 × 106 cycles (770 MPa), tensile strength (1323 MPa), and apparent hardness (38 HRC). The impact energy of Fe-3Cr-0.5Mo-4Ni-0.5C steel is twice as high as those of the ordinary high-strength PM steels. These findings demonstrate that a high-strength PM steel with high-toughness can be produced by optimized alloy design and microstructure.

  16. Uranium silicide pellet fabrication by powder metallurgy for accident tolerant fuel evaluation and irradiation

    SciTech Connect

    Harp, Jason Michael; Lessing, Paul Alan; Hoggan, Rita Elaine

    2015-06-21

    In collaboration with industry, Idaho National Laboratory is investigating uranium silicide for use in future light water reactor fuels as a more accident resistant alternative to uranium oxide base fuels. Specifically this project was focused on producing uranium silicide (U3Si2) pellets by conventional powder metallurgy with a density greater than 94% of the theoretical density. This work has produced a process to consistently produce pellets with the desired density through careful optimization of the process. Milling of the U3Si2 has been optimized and high phase purity U3Si2 has been successfully produced. Results are presented from sintering studies and microstructural examinations that illustrate the need for a finely ground reproducible particle size distribution in the source powder. The optimized process was used to produce pellets for the Accident Tolerant Fuel-1 irradiation experiment. The average density of these pellets was 11.54 ±0.06 g/cm3. Additional characterization of the pellets by scaning electron microscopy and X-ray diffraction has also been performed. As a result, pellets produced in this work have been encapsulated for irradiation, and irradiation in the Advanced Test Reactor is expected soon.

  17. Active Thermography for the Detection of Defects in Powder Metallurgy Compacts

    NASA Astrophysics Data System (ADS)

    Benzerrouk, Souheil; Ludwig, Reinhold; Apelian, Diran

    2007-03-01

    Active thermography is an established NDE technique that has become the method of choice in many industrial applications which require non-contact access to the parts under test. Unfortunately, when conducting on-line infrared (IR) inspection of powder metallic compacts, complications can arise due the generally low emissivity of metals and the thermally noisy environment typically encountered in manufacturing plants. In this paper we present results of an investigation that explores the suitability of active IR imaging of powder metallurgy compacts for the detection of surface and sub-surface defects in the pre-sinter state and in an on-line manufacturing setting to ensure complete quality assurance. Additional off-line tests can be carried out for statistical quality analyses. In this research, the IR imaging of sub-surface defects is based on a transient instrumentation approach that relies on an electric control system which synchronizes and monitors the thermal response due to an electrically generated heat source. Preliminary testing reveals that this newly developed pulsed thermography system can be employed for the detection of subsurface defects in green-state parts. Practical measurements agree well with theoretical predictions. The inspection approach being developed can be used for the testing of green-state compacts as they exit the compaction press at speeds of up to 1,000 parts per hour.

  18. Characterisation of titanium-titanium boride composites processed by powder metallurgy techniques

    SciTech Connect

    Selva Kumar, M.; Chandrasekar, P.; Chandramohan, P.; Mohanraj, M.

    2012-11-15

    In this work, a detailed characterisation of titanium-titanium boride composites processed by three powder metallurgy techniques, namely, hot isostatic pressing, spark plasma sintering and vacuum sintering, was conducted. Two composites with different volume percents of titanium boride reinforcement were used for the investigation. One was titanium with 20% titanium boride, and the other was titanium with 40% titanium boride (by volume). Characterisation was performed using X-ray diffraction, electron probe micro analysis - energy dispersive spectroscopy and wavelength dispersive spectroscopy, image analysis and scanning electron microscopy. The characterisation results confirm the completion of the titanium boride reaction. The results reveal the presence of titanium boride reinforcement in different morphologies such as needle-shaped whiskers, short agglomerated whiskers and fine plates. The paper also discusses how mechanical properties such as microhardness, elastic modulus and Poisson's ratio are influenced by the processing techniques as well as the volume fraction of the titanium boride reinforcement. - Highlights: Black-Right-Pointing-Pointer Ti-TiB composites were processed by HIP, SPS and vacuum sintering. Black-Right-Pointing-Pointer The completion of Ti-TiB{sub 2} reaction was confirmed by XRD, SEM and EPMA studies. Black-Right-Pointing-Pointer Hardness and elastic properties of Ti-TiB composites were discussed. Black-Right-Pointing-Pointer Processing techniques were compared with respect to their microstructure.

  19. Emissions from Pre-Hispanic Metallurgy in the South American Atmosphere

    PubMed Central

    De Vleeschouwer, François; Vanneste, Heleen; Mauquoy, Dmitri; Piotrowska, Natalia; Torrejón, Fernando; Roland, Thomas; Stein, Ariel; Le Roux, Gaël

    2014-01-01

    Metallurgical activities have been undertaken in northern South America (NSA) for millennia. However, it is still unknown how far atmospheric emissions from these activities have been transported. Since the timing of metallurgical activities is currently estimated from scarce archaeological discoveries, the availability of reliable and continuous records to refine the timing of past metal deposition in South America is essential, as it provides an alternative to discontinuous archives, as well as evidence for global trace metal transport. We show in a peat record from Tierra del Fuego that anthropogenic metals likely have been emitted into the atmosphere and transported from NSA to southern South America (SSA) over the last 4200 yrs. These findings are supported by modern time back-trajectories from NSA to SSA. We further show that apparent anthropogenic Cu and Sb emissions predate any archaeological evidence for metallurgical activities. Lead and Sn were also emitted into the atmosphere as by-products of Inca and Spanish metallurgy, whereas local coal-gold rushes and the industrial revolution contributed to local contamination. We suggest that the onset of pre-Hispanic metallurgical activities is earlier than previously reported from archaeological records and that atmospheric emissions of metals were transported from NSA to SSA. PMID:25353346

  20. Selective wet chemical etching of metallic thin films designed by laser interference metallurgy (LIMET)

    NASA Astrophysics Data System (ADS)

    Catrin, Rodolphe; Gachot, Carsten; Marchand, Günter; Schmid, Ulrich; Mücklich, Frank

    2009-05-01

    The physical and chemical behaviour of materials is strongly correlated with their microstructure. Therefore, much effort is invested in the advanced microstructural design of metallic thin films. Laser Interference Metallurgy (LIMET) is used to locally tune the grain architecture of metallic thin films from the nanoto the microscale. This means a defined size and orientation of the grains with lateral periodicity, by interfering on the sample surface two or more laser beams of a high power nanosecond pulsed Nd:YAG laser. This technique enables the local nucleation and crystallization of amorphous or nanocrystalline metallic thin films, thus combining nano- and microcrystalline regions ordered in periodic line- or lattice-like arrangements in a composite architecture. After having locally modified the microstructure of e-beam evaporated Pt and Au thin films by laser irradiation a wet chemical etching procedure was induced in hot aqua regia. Doing so, a selective etching is achieved without using conventional lithography. Due to the laser-induced recrystallization in periodic structures, these microcrystalline zones of specific oriented grains show a higher resistance against the wet chemical etchant than the as-deposited, nanocrystalline areas, which are completely removed down to the substrate. Therefore, this procedure may have the potential to be an alternative, low cost approach to conventional lithographic techniques and provides a novel method for a straight-forward patterning of metallic thin films.

  1. The substitution of nickel for cobalt in hot isostatically pressed powder metallurgy UDIMET 700 alloys

    NASA Technical Reports Server (NTRS)

    Harf, F. H.

    1985-01-01

    Nickel was substituted in various proportions for cobalt in a series of five hot-isostatically-pressed powder metallurgy alloys based on the UDIMET 700 composition. These alloys were given 5-step heat treatments appropriate for use in turbine engine disks. The resultant microstructures displayed three distinct sizes of gamma-prime particles in a gamma matrix. The higher cobalt-content alloys contained larger amounts of the finest gamma-prime particles, and had the lowest gamma-gamma-prime lattice mismatch. While all alloys had approximately the same tensile properties at 25 and 650 gamma C, the rupture lives at 650 and 760 C peaked in the alloys with cobalt contents between 12.7 and 4.3 pct. Minimum creep rates increased as cobalt contents were lowered, suggesting their correlation with the gamma-prime particle size distribution and the gamma-gamma-prime mismatch. It was also found that, on overaging at temperatures higher than suitable for turbine disk use, the high cobalt-content alloys were prone to sigma phase formation.

  2. Uranium silicide pellet fabrication by powder metallurgy for accident tolerant fuel evaluation and irradiation

    DOE PAGESBeta

    Harp, Jason Michael; Lessing, Paul Alan; Hoggan, Rita Elaine

    2015-06-21

    In collaboration with industry, Idaho National Laboratory is investigating uranium silicide for use in future light water reactor fuels as a more accident resistant alternative to uranium oxide base fuels. Specifically this project was focused on producing uranium silicide (U3Si2) pellets by conventional powder metallurgy with a density greater than 94% of the theoretical density. This work has produced a process to consistently produce pellets with the desired density through careful optimization of the process. Milling of the U3Si2 has been optimized and high phase purity U3Si2 has been successfully produced. Results are presented from sintering studies and microstructural examinationsmore » that illustrate the need for a finely ground reproducible particle size distribution in the source powder. The optimized process was used to produce pellets for the Accident Tolerant Fuel-1 irradiation experiment. The average density of these pellets was 11.54 ±0.06 g/cm3. Additional characterization of the pellets by scaning electron microscopy and X-ray diffraction has also been performed. As a result, pellets produced in this work have been encapsulated for irradiation, and irradiation in the Advanced Test Reactor is expected soon.« less

  3. The substitution of nickel for cobalt in hot isostatically pressed powder metallurgy UDIMET 700 alloys

    NASA Astrophysics Data System (ADS)

    Harf, Fredric H.

    1985-06-01

    Nickel was substituted in various proportions for cobalt in a series of five hot-isostatically-pressed powder metallurgy alloys based on the UDIMET 700 composition. These alloys were given 5-step heat treatments appropriate for use in turbine engine disks. The resultant microstructures displayed three distinct sizes of γ' particles in a γ matrix. The higher cobalt-content alloys contained larger amounts of the finest γ' particles, and had the lowest γ-γ' lattice mismatch. While all alloys had approximately the same tensile properties at 25 and 650°C, the rupture lives at 650 and 760°C peaked in the alloys with cobalt contents between 12.7 and 4.3 pct. Minimum creep rates increased as cobalt contents were lowered, suggesting their correlation with the γ' particle size distribution and the γ-γ' mismatch. It was also found that, on overaging at temperatures higher than suitable for turbine disk use, the high cobalt-content alloys were prone to sigma phase formation.

  4. Uranium silicide pellet fabrication by powder metallurgy for accident tolerant fuel evaluation and irradiation

    NASA Astrophysics Data System (ADS)

    Harp, Jason M.; Lessing, Paul A.; Hoggan, Rita E.

    2015-11-01

    In collaboration with industry, Idaho National Laboratory is investigating uranium silicide for use in future light water reactor fuels as a more accident resistant alternative to uranium oxide base fuels. Specifically this project was focused on producing uranium silicide (U3Si2) pellets by conventional powder metallurgy with a density greater than 94% of the theoretical density. This work has produced a process to consistently produce pellets with the desired density through careful optimization of the process. Milling of the U3Si2 has been optimized and high phase purity U3Si2 has been successfully produced. Results are presented from sintering studies and microstructural examinations that illustrate the need for a finely ground reproducible particle size distribution in the source powder. The optimized process was used to produce pellets for the Accident Tolerant Fuel-1 irradiation experiment. The average density of these pellets was 11.54 ± 0.06 g/cm3. Additional characterization of the pellets by scanning electron microscopy and X-ray diffraction has also been performed. Pellets produced in this work have been encapsulated for irradiation, and irradiation in the Advanced Test Reactor is expected soon.

  5. Application of powder metallurgy techniques to produce improved bearing elements for liquid rocket engines

    NASA Technical Reports Server (NTRS)

    Moracz, D. J.; Shipley, R. J.; Moxson, V. S.; Killman, R. J.; Munson, H. E.

    1992-01-01

    The objective was to apply powder metallurgy techniques for the production of improved bearing elements, specifically balls and races, for advanced cryogenic turbopump bearings. The materials and fabrication techniques evaluated were judged on the basis of their ability to improve fatigue life, wear resistance, and corrosion resistance of Space Shuttle Main Engine (SSME) propellant bearings over the currently used 440C. An extensive list of candidate bearing alloys in five different categories was considered: tool/die steels, through hardened stainless steels, cobalt-base alloys, and gear steels. Testing of alloys for final consideration included hardness, rolling contact fatigue, cross cylinder wear, elevated temperature wear, room and cryogenic fracture toughness, stress corrosion cracking, and five-ball (rolling-sliding element) testing. Results of the program indicated two alloys that showed promise for improved bearing elements. These alloys were MRC-2001 and X-405. 57mm bearings were fabricated from the MRC-2001 alloy for further actual hardware rig testing by NASA-MSFC.

  6. Development and Processing of Novel Aluminum Powder Metallurgy Materials for Heat Sink Applications

    NASA Astrophysics Data System (ADS)

    Smith, L. J. B.; Corbin, S. F.; Hexemer, R. L.; Donaldson, I. W.; Bishop, Donald Paul

    2014-02-01

    The objective of this research was to design aluminum powder metallurgy (PM) alloys and processing strategies that yielded sintered products with thermal properties that rivaled those of the cast and wrought aluminum alloys traditionally employed in heat sink manufacturing. Research has emphasized PM alloys within the Al-Mg-Sn system. In one sub-theme of research, the general processing response of each PM alloy was investigated through a combination of sintering trials, sintered density measurements, and microstructural assessments. In the second, the thermal properties of sintered products were studied in detail. Thermal conductivity was first determined using a calculated approach through discrete measurements of specific heat capacity, thermal diffusivity, and density and subsequently verified using a transient plane source technique on larger specimens. Experimental PM alloys achieved >99 pct theoretical density and exhibited thermal conductivity that ranged from 179 to 225 W/m K. Thermal performance was largely dominated by the amount of magnesium present within the aluminum grains and, in turn, bulk alloy chemistry. Data confirmed that the novel PM alloys were highly competitive with even the most advanced heat sink materials such as wrought 6063 and 6061.

  7. Interfacial metallurgy study of brazed joints between tungsten and fusion related materials for divertor design

    NASA Astrophysics Data System (ADS)

    Zhang, Yuxuan; Galloway, Alexander; Wood, James; Robbie, Mikael Brian Olsson; Easton, David; Zhu, Wenzhong

    2014-11-01

    In the developing DEMO divertor, the design of joints between tungsten to other fusion related materials is a significant challenge as a result of the dissimilar physical metallurgy of the materials to be joined. This paper focuses on the design and fabrication of dissimilar brazed joints between tungsten and fusion relevant materials such as EUROFER 97, oxygen-free high thermal conductivity (OFHC) Cu and SS316L using a gold based brazing foil. The main objectives are to develop acceptable brazing procedures for dissimilar joining of tungsten to other fusion compliant materials and to advance the metallurgical understanding within the interfacial region of the brazed joint. Four different butt-type brazed joints were created and characterised, each of which were joined with the aid of a thin brazing foil (Au80Cu19Fe1, in wt.%). Microstructural characterisation and elemental mapping in the transition region of the joint was undertaken and, thereafter, the results were analysed as was the interfacial diffusion characteristics of each material combination produced. Nano-indentation tests are performed at the joint regions and correlated with element composition information in order to understand the effects of diffused elements on mechanical properties. The experimental procedures of specimen fabrication and material characterisation methods are presented. The results of elemental transitions after brazing are reported. Elastic modulus and nano-hardness of each brazed joints are reported.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    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. Project supported by the National Natural Science Foundation of China (Grant Nos. 50974016 and 50071014).

  9. Bridging the gap between metallurgy and fatigue reliability of hydraulic turbine runners

    NASA Astrophysics Data System (ADS)

    Thibault, D.; Gagnon, M.; Godin, S.

    2014-03-01

    The failure of hydraulic turbine runners is a very rare event. Hence, in order to assess the reliability of these components, one cannot rely on statistical models based on the number of failures in a given population. However, as there is a limited number of degradation mechanisms involved, it is possible to use physically-based reliability models. Such models are more complicated but have the advantage of being able to account for physical parameters in the prediction of the evolution of runner degradation. They can therefore propose solutions to help improve reliability. With the use of such models, the effect of materials properties on runner reliability can easily be illustrated. This paper will present a brief review of the Kitagawa-Takahashi diagram that links the damage tolerance approach, based on fracture mechanics, to the stress or strain-life approaches. This diagram is at the centre of the reliability model used in this study. Using simplified response spectra obtained from on-site runner stress measurements, the paper will show how fatigue reliability is impacted by materials fatigue properties, namely fatigue crack propagation behaviour and fatigue limit obtained on S-N curves. It will also present a review of the most important microstructural features of 13%Cr- 4%Ni stainless steels used for runner manufacturing and will review how they influence fatigue properties in an effort to bridge the gap between metallurgy and turbine runners reliability.

  10. Emissions from pre-Hispanic metallurgy in the South American atmosphere.

    PubMed

    De Vleeschouwer, François; Vanneste, Heleen; Mauquoy, Dmitri; Piotrowska, Natalia; Torrejón, Fernando; Roland, Thomas; Stein, Ariel; Le Roux, Gaël

    2014-01-01

    Metallurgical activities have been undertaken in northern South America (NSA) for millennia. However, it is still unknown how far atmospheric emissions from these activities have been transported. Since the timing of metallurgical activities is currently estimated from scarce archaeological discoveries, the availability of reliable and continuous records to refine the timing of past metal deposition in South America is essential, as it provides an alternative to discontinuous archives, as well as evidence for global trace metal transport. We show in a peat record from Tierra del Fuego that anthropogenic metals likely have been emitted into the atmosphere and transported from NSA to southern South America (SSA) over the last 4200 yrs. These findings are supported by modern time back-trajectories from NSA to SSA. We further show that apparent anthropogenic Cu and Sb emissions predate any archaeological evidence for metallurgical activities. Lead and Sn were also emitted into the atmosphere as by-products of Inca and Spanish metallurgy, whereas local coal-gold rushes and the industrial revolution contributed to local contamination. We suggest that the onset of pre-Hispanic metallurgical activities is earlier than previously reported from archaeological records and that atmospheric emissions of metals were transported from NSA to SSA. PMID:25353346

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

    NASA Astrophysics Data System (ADS)

    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).

  12. Ultra-High Strength and Ductile Lamellar-Structured Powder Metallurgy Binary Ti-Ta Alloys

    NASA Astrophysics Data System (ADS)

    Liu, Yong; Xu, Shenghang; Wang, Xin; Li, Kaiyang; Liu, Bin; Wu, Hong; Tang, Huiping

    2016-03-01

    Ultra-high strength and ductile powder metallurgy (PM) binary Ti-20at.%Ta alloy has been fabricated via sintering from elemental Ti and Ta powders and subsequent hot swaging and annealing. The microstructural evolution and mechanical properties in each stage were evaluated. Results show that inhomogeneous microstructures with Ti-rich and Ta-rich areas formed in the as-sintered Ti-Ta alloys due to limited diffusion of Ta. In addition, Kirkendall porosity was observed as a result of the insufficient diffusion of Ta. Annealing at 1000°C for up to 24 h failed to eliminate the pores. Hot swaging eliminated the residual sintering porosity and created a lamellar microstructure, consisting of aligned Ta-enriched and Ti-enriched phases. The hot-swaged and annealed PM Ti-20Ta alloy achieved an ultimate tensile strength of 1600 MPa and tensile elongation of more than 25%, due to its unique lamellar microstructure including the high toughness of Ta-enriched phases, the formation of α phase in the β matrix and the refined lamellae.

  13. Application of powder metallurgy technique to produce improved bearing elements for cryogenic aerospace engine turbopumps

    NASA Technical Reports Server (NTRS)

    Moxson, V. S.; Moracz, D. J.; Bhat, B. N.; Dolan, F. J.; Thom, R.

    1987-01-01

    Traditionally, vacuum melted 440C stainless steel is used for high performance bearings for aerospace cryogenic systems where corrosion due to condensation is a major concern. For the Space Shuttle Main Engine (SSME), however, 440C performance in the high-pressure turbopumps has been marginal. A basic assumption of this study was that powder metallurgy, rather than cast/wrought, processing would provide the finest, most homogeneous bearing alloy structure. Preliminary testing of P/M alloys (hardness, corrosion resistance, wear resistance, fatigue resistance, and fracture toughness) was used to 'de-select' alloys which did perform as well as baseline 440C. Five out of eleven candidate materials (14-4/6V, X-405, MRC-2001, T-440V, and D-5) based on preliminary screening were selected for the actual rolling-sliding five-ball testing. The results of this test were compared with high-performance vacuum-melted M50 bearing steel. The results of the testing indicated outstanding performance of two P/M alloys, X-405 and MRC-2001, which eventually will be further evaluated by full-scale bearing testing.

  14. Development of Cu-E-Glass Fiber Composites by Powder Metallurgy Route

    NASA Astrophysics Data System (ADS)

    Bhuyan, Pallabi; Singh, Harspreet; Kumar, Lailesh; Sharma, Nidhi; Panda, Deepankar; Verma, Deepanshu; NasmulAlam, Syed

    2016-02-01

    Cu-E glass fiber composites were developed with different vol. % of E-glass fiber (10, 20, 30 and 40 vol. %) by powder metallurgy route. Both as-received Cu and nanostructured Cu developed by milling as-received Cu powder for 20 h were used to develop various Cu-E-glass fiber composites. The effect of using as-received Cu powder and nanostructured Cu powder on the properties of the various Cu-E-glass fiber composites was analysed. The samples were sintered at 900oC for 1 h in inert atmosphere. The results show good bonding between the matrix and the reinforcement and there is homogeneous distribution of the reinforcement in the matrix.. The hardness of the Cu-E-glass fiber composites was found to increase from 0.8GPa to 2.7GPa with increase in vol. % of the glass fiber in case of unmilled and from 1.2GPa to 2.9GPa for the milled Cu-E-glass fiber composites. The as-milled Cu-E- glass fiber composites shows better densification and sinterability compared to the unmilled CuE-glass fiber composites

  15. An investigation of wear behaviors of different Monel alloys produced by powder metallurgy

    NASA Astrophysics Data System (ADS)

    Esgin, U.; Özyürek, D.; Kaya, H.

    2016-04-01

    In the present study, wear behaviors of Monel 400, Monel 404, Monel R-405 and Monel K-500 alloys produced by Powder Metallurgy (P/M) method were investigated. These compounds prepared from elemental powders were cold-pressed (600 MPa) and then, sintered at 1150°C for 2 hours and cooled down to the room temperature in furnace environment. Monel alloys produced by the P/M method were characterized through scanning electron microscope (SEM+EDS), X-ray diffraction (XRD), hardness and density measurements. In wear tests, standard pin-on-disk type device was used. Specimens produced within four different Monel Alloys were tested under 1ms-1 sliding speed, under three different loads (20N, 30N and 40N) and five different sliding distances (400-2000 m). The results show that Monel Alloys have γ matrix and that Al0,9Ni4,22 intermetallic phase was formed in the structure. Also, the highest hardness value was measured with the Monel K-500 alloy. In wear tests, the maximum weight loss according to the sliding distance, was observed in Monel 400 and Monel 404 alloys while the minimum weight loss was achieved by the Monel K-500 alloy.

  16. Active Thermography for the Detection of Defects in Powder Metallurgy Compacts

    SciTech Connect

    Benzerrouk, Souheil; Ludwig, Reinhold; Apelian, Diran

    2007-03-21

    Active thermography is an established NDE technique that has become the method of choice in many industrial applications which require non-contact access to the parts under test. Unfortunately, when conducting on-line infrared (IR) inspection of powder metallic compacts, complications can arise due the generally low emissivity of metals and the thermally noisy environment typically encountered in manufacturing plants. In this paper we present results of an investigation that explores the suitability of active IR imaging of powder metallurgy compacts for the detection of surface and sub-surface defects in the pre-sinter state and in an on-line manufacturing setting to ensure complete quality assurance. Additional off-line tests can be carried out for statistical quality analyses. In this research, the IR imaging of sub-surface defects is based on a transient instrumentation approach that relies on an electric control system which synchronizes and monitors the thermal response due to an electrically generated heat source. Preliminary testing reveals that this newly developed pulsed thermography system can be employed for the detection of subsurface defects in green-state parts. Practical measurements agree well with theoretical predictions. The inspection approach being developed can be used for the testing of green-state compacts as they exit the compaction press at speeds of up to 1,000 parts per hour.

  17. Tribological properties of PM212 - A high temperature, self-lubricating, powder metallurgy composite

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Sliney, Harold E.

    1990-01-01

    This paper describes a research program to develop and evaluate a new high temperature, self-lubricating powder metallurgy composite, PM212. PM212 has the same composition as the plasma-sprayed coating, PS212, which contains 70 wt percent metal-bonded chromium carbide, 15 wt percent silver and 15 wt percent barium fluoride/calcium fluoride eutectic. The carbide acts as a wear resistant matrix and the silver and fluorides act as low and high temperature lubricants, respectively. The material is prepared by sequential cold press, cold isostatic pressing and sintering techniques. In this study, hemispherically tipped wear pins of PM212 were prepared and slid against superalloy disks at temperatures from 25 to 850 C in air in a pin-on-disk tribometer. Friction coefficients range from 0.29 to 0.38 and the wear of both the composite pins and superalloy disks was moderate to low in the 10(exp -5) to 10(exp -6) cubic mm/N-m range. Preliminary tests indicate that the material has a compressive strength of at least 130 MPa over the entire temperature range of 25 to 900 C. This material has promise for use as seal inserts, bushings, small inside diameter parts and other applications where plasma-sprayed coatings are impractical or too costly.

  18. Characterization of the carbides and the martensite phase in powder-metallurgy high-speed steel

    SciTech Connect

    Godec, Matjaz; Batic, Barbara Setina; Mandrino, Djordje; Nagode, Ales; Leskovsek, Vojteh; Skapin, Sreco D.; Jenko, Monika

    2010-04-15

    A microstructural characterization of the powder-metallurgy high-speed-steel S390 Microclean was performed based on an elemental distribution of the carbide phase as well as crystallographic analyses. The results showed that there were two types of carbides present: vanadium-rich carbides, which were not chemically homogeneous and exhibited a tungsten-enriched or tungsten-depleted central area; and chemically homogeneous tungsten-rich M{sub 6}C-type carbides. Despite the possibility of chemical inhomogenities, the crystallographic orientation of each of the carbides was shown to be uniform. Using electron backscatter diffraction the vanadium-rich carbides were determined to be either cubic VC or hexagonal V{sub 6}C{sub 5}, while the tungsten-rich carbides were M{sub 6}C. The electron backscatter diffraction results were also verified using X-ray diffraction. Several electron backscatter diffraction pattern maps were acquired in order to define the fraction of each carbide phase as well as the amount of martensite phase. The fraction of martensite was estimated using band-contrast images, while the fraction of carbides was calculated using the crystallographic data.

  19. Tribological properties of PM212: A high-temperature, self-lubricating, powder metallurgy composite

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Sliney, Harold E.

    1989-01-01

    This paper describes a research program to develop and evaluate a new high temperature, self-lubricating powder metallurgy composite, PM212. PM212 has the same composition as the plasma-sprayed coating, PS212, which contains 70 wt percent metal-bonded chromium carbide, 15 wt percent silver and 15 wt percent barium fluoride/calcium fluoride eutectic. The carbide acts as a wear resistant matrix and the silver and fluorides act as low and high temperature lubricants, respectively. The material is prepared by sequential cold press, cold isostatic pressing and sintering techniques. In this study, hemispherically tipped wear pins of PM212 were prepared and slid against superalloy disks at temperatures from 25 to 850 C in air in a pin-on-disk tribometer. Friction coefficients range from 0.29 to 0.38 and the wear of both the composite pins and superalloy disks was moderate to low in the 10(exp -5) to 10(exp -6) cubic mm/N-m range. Preliminary tests indicate that the material has a compressive strength of at least 130 MPa over the entire temperature range of 25 to 900 C. This material has promise for use as seal inserts, bushings, small inside diameter parts and other applications where plasma-sprayed coatings are impractical or too costly.

  20. Effects of Under Bump Metallurgy (UBM) Materials on the Corrosion of Electroless Nickel Films

    NASA Astrophysics Data System (ADS)

    Yu, Jin; Kim, Kyoungdoc

    2015-07-01

    The "black pad" phenomenon, which refers to the blackening of electroless-plated nickel-phosphorus [Ni(P)] films during the immersion Au process, is reproduced using pure chemicals and its fundamental mechanisms are investigated. In the present analysis, under bump metallurgy (UBM) materials have profound effects on the black pad susceptibility, and the presence of abnormally large nodules (ALNs) is essential to the black pad occurrence. The Ni(P) films over Cu, Ag, and Au substrates all exhibit ALNs and are susceptible to black pads, while those over Ni and Co substrates do not have ALNs and therefore are not susceptible to black pad. In the former cases, submicron scale nodular variations of the surface curvature lead to variations in the P concentration in the Ni(P) films, which induces sufficiently large potential differences to drive galvanic corrosion when exposed to the electrolyte, which is a gold cyanide solution in this study. The UBM effect is ascribed to differences in the Ni(P) film growth mode, where the transition from a layer-by-layer growth mode to an island growth mode is easier over Cu, Ag, and Au UBMs.

  1. Analysis of Load Transfer Mechanism in Cu Reinforced with Carbon Nanotubes Fabricated by Powder Metallurgy Route

    NASA Astrophysics Data System (ADS)

    Akbarpour, Mohammad Reza

    2016-05-01

    In this research, ductile and high-strength Cu-carbon nanotube (Cu-CNT) composites with different volume fractions of CNTs were fabricated using powder metallurgy route including mechanical milling and hot pressing and microstructure and tensile properties of the resulting materials were studied. Microstructural characterization through scanning electron microscope and quantifying the CNT agglomeration revealed that uniform dispersion of CNTs in Cu matrix decreases with increasing CNT volume fraction. In case of the higher volume fraction of CNTs (i.e., 8 vol.%), ~ 40% of CNTs were observed as agglomerates in the microstructure. Compared to unreinforced Cu, the yield and ultimate tensile strengths increased considerably (about 33% and 12%, respectively) with incorporation of CNTs up to 4 vol.%, but remained constant afterward. Meanwhile, the elongation decreased from 15.6% for Cu to 6.9% for Cu with 8 vol.% CNT. The relationship between the change in yield strength of the composite and the microstructure was investigated using analytical models. The results showed good consistency between calculated and measured data when the negative effect of CNT agglomerates in the models were taken into account.

  2. Niobium-titanium superconductors produced by powder metallurgy having artificial flux pinning centers

    DOEpatents

    Jablonski, Paul D.; Larbalestier, David C.

    1993-01-01

    Superconductors formed by powder metallurgy have a matrix of niobium-titanium alloy with discrete pinning centers distributed therein which are formed of a compatible metal. The artificial pinning centers in the Nb-Ti matrix are reduced in size by processing steps to sizes on the order of the coherence length, typically in the range of 1 to 10 nm. To produce the superconductor, powders of body centered cubic Nb-Ti alloy and the second phase flux pinning material, such as Nb, are mixed in the desired percentages. The mixture is then isostatically pressed, sintered at a selected temperature and selected time to produce a cohesive structure having desired characteristics without undue chemical reaction, the sintered billet is reduced in size by deformation, such as by swaging, the swaged sample receives heat treatment and recrystallization and additional swaging, if necessary, and is then sheathed in a normal conducting sheath, and the sheathed material is drawn into a wire. The resulting superconducting wire has second phase flux pinning centers distributed therein which provide enhanced J.sub.ct due to the flux pinning effects.

  3. Factors Influencing Dwell Fatigue Cracking in Notches of Powder Metallurgy Superalloys

    NASA Technical Reports Server (NTRS)

    Gabb, T. P.; Telesman, J.; Ghosn, L.; Garg, A.; Gayda, J.

    2011-01-01

    The influences of heat treatment and cyclic dwells on the notch fatigue resistance of powder metallurgy disk superalloys were investigated for low solvus high refractory (LSHR) and ME3 disk alloys. Disks were processed to produce material conditions with varied microstructures and associated mechanical properties. Notched specimens were first subjected to baseline dwell fatigue cycles having a dwell at maximum load, as well as tensile, stress relaxation, creep rupture, and dwell fatigue crack growth tests at 704 C. Several material heat treatments displayed a bimodal distribution of fatigue life with the lives varying by two orders-of-magnitude, while others had more consistent fatigue lives. This response was compared to other mechanical properties, in search of correlations. The wide scatter in baseline dwell fatigue life was observed only for material conditions resistant to stress relaxation. For selected materials and conditions, additional tests were then performed with the dwells shifted in part or in total to minimum tensile load. The tests performed with dwells at minimum load exhibited lower fatigue lives than max dwell tests, and also exhibited early crack initiation and a substantial increase in the number of initiation sites. These results could be explained in part by modeling evolution of peak stresses in the notch with continued dwell fatigue cycling. Fatigue-environment interactions were determined to limit life for the fatigue cycles with dwells.

  4. Dwell Notch Low Cycle Fatigue Behavior of a Powder Metallurgy Nickel Disk Alloy

    NASA Technical Reports Server (NTRS)

    Telesman, J.; Gabb, T. P.; Yamada, Y.; Ghosn, L. J.; Jayaraman, N.

    2012-01-01

    A study was conducted to determine the processes which govern dwell notch low cycle fatigue (NLCF) behavior of a powder metallurgy (P/M) ME3 disk superalloy. The emphasis was placed on the environmentally driven mechanisms which may embrittle the highly stressed notch surface regions and reduce NLCF life. In conjunction with the environmentally driven notch surface degradation processes, the visco-plastic driven mechanisms which can significantly change the notch root stresses were also considered. Dwell notch low cycle fatigue testing was performed in air and vacuum on a ME3 P/M disk alloy specimens heat treated using either a fast or a slow cooling rate from the solutioning treatment. It was shown that dwells at the minimum stress typically produced a greater life debit than the dwells applied at the maximum stress, especially for the slow cooled heat treatment. Two different environmentally driven failure mechanisms were identified as the root cause of early crack initiation in the min dwell tests. Both of these failure mechanisms produced mostly a transgranular crack initiation failure mode and yet still resulted in low NLCF fatigue lives. The lack of stress relaxation during the min dwell tests produced higher notch root stresses which caused early crack initiation and premature failure when combined with the environmentally driven surface degradation mechanisms. The importance of environmental degradation mechanisms was further highlighted by vacuum dwell NLCF tests which resulted in considerably longer NLCF lives, especially for the min dwell tests.

  5. State-of-the-art of recycling e-wastes by vacuum metallurgy separation.

    PubMed

    Zhan, Lu; Xu, Zhenming

    2014-12-16

    In recent era, more and more electric and electronic equipment wastes (e-wastes) are generated that contain both toxic and valuable materials in them. Most studies focus on the extraction of valuable metals like Au, Ag from e-wastes. However, the recycling of metals such as Pb, Cd, Zn, and organics has not attracted enough attentions. Vacuum metallurgy separation (VMS) processes can reduce pollution significantly using vacuum technique. It can effectively recycle heavy metals and organics from e-wastes in an environmentally friendly way, which is beneficial for both preventing the heavy metal contaminations and the sustainable development of resources. VMS can be classified into several methods, such as vacuum evaporation, vacuum carbon reduction and vacuum pyrolysis. This paper respectively reviews the state-of-art of these methods applied to recycling heavy metals and organics from several kinds of e-wastes. The method principle, equipment used, separating process, optimized operating parameters and recycling mechanism of each case are illustrated in details. The perspectives on the further development of e-wastes recycling by VMS are also presented. PMID:25407107

  6. Tribological behavior of liquid metallurgy-processed AA 6061-B4C composites

    NASA Astrophysics Data System (ADS)

    Monikandan, V. V.; Joseph, M. A.; Rajendrakumar, P. K.; Sreejith, M.

    2015-01-01

    Aluminum metal matrix composites (AMMCs) possess improved properties compared to their monolithic counterparts and serve as a reliable alternative to replace them for applications that are considered as their niche. In the present investigation, 6061 Al alloy-10 wt% B4C composite is fabricated through liquid metallurgy stir casting technique and analyzed for its tribological characteristics. The uniform distribution of B4C reinforcement particles in the composite is achieved by the above route and is characterized using microstructure analysis and x-ray diffraction spectrum. The dry wear tests have been conducted under ambient conditions using a pin-on-disc tribometer. The worn surface and debris of the composite are also characterized using a scanning electron microscope (SEM) and energy-dispersive x-ray spectroscopy (EDS). It is found that the combination of adhesion, delamination and abrasion constitute the predominant wear mechanism and this is influenced by the B4C particles, applied load, sliding distance and speed. The wear and friction coefficient increase with increase in applied load for all the load conditions studied. While the sliding speed fosters the engendering of a mechanically mixed layer (MML) to reduce the wear and friction coefficient, in contrast, the increase in sliding distance scuttles the MML formation owing to abrasion induced by the hard B4C particles.

  7. Tuned wettability of material surfaces for tribological applications in miniaturized systems by laser interference metallurgy

    NASA Astrophysics Data System (ADS)

    Gachot, C.; Hans, M.; Catrin, R.; Schmid, U.; Mücklich, F.

    2009-05-01

    Innovative surfaces are successful, if we succeed to put in the correct place the correct property with technological efficiency. Until now, material surfaces can be systematically structured in different ways in order to fulfil chemical or mechanical requirements such as corrosion protection or wear resistance for example. Moreover, the properties of materials are strongly related to their microstructure as well as to their spatial distribution. For that reason, the design of materials with tailored microstructures is a key for the functionalization of surfaces. This is possible by an artificial fabrication technique called Laser Interference Metallurgy. In this context, textured or functionalized surfaces are beneficial in overcoming stiction and adhesion in MEMS devices. With regard to tribological applications, a systematic study of the effect of geometrically differing laser interference patterns on the wetting behaviour of metallic gold thin films with a thickness of about 300 nm and 125 μm thick polyimide foils should be presented. It could be shown that in case of gold films, a laser interference patterning reinforces the hydrophilic sample behavior whereas the polyimide foils reveal a significant increase in hydrophobicity after the laser patterning process. Both wetting regimes are advantageous under dry or lubricated friction conditions. The corresponding geometrical limits of the abovementioned method concerning the structure depth, periodicity and pattern form has been determined. All the samples have been characterized by scanning electron and focused ion beam microscopy and white light interferometry. Additionally, IR spectroscopy has been applied to the polyimide samples in order to separate topographic and chemical influences.

  8. Copper-Carbon and Aluminum-Carbon Composites Fabricated by Powder Metallurgy Processes

    NASA Astrophysics Data System (ADS)

    Silvain, Jean-François; Veillère, Amélie; Lu, Yongfeng

    2014-07-01

    The increase in both power and packing densities in power electronic devices has led to an increase in the market demand for effective heat-dissipating materials, with high thermal conductivity and thermal- expansion coefficient compatible with chip materials still ensuring the reliability of the power modules. In this context, metal matrix composites: carbon fibers and diamond-reinforced copper and aluminum matrix composites among them are considered very promising as a next generation of thermal-management materials in power electronic packages. These composites exhibit enhanced thermal properties compared to pure copper combined with lower density. This article presents the fabrication techniques of copper/carbon fibers and copper/diamond and aluminum/carbon fibers composite films by powder metallurgy and hot pressing. The thermal analyses clearly indicate that interfacial treatments are required in these composites to achieve high thermomechanical properties. Interfaces (through novel chemical and processing methods), when selected carefully and processed properly will form the right chemical/mechanical link between metal and carbon, enhancing all the desired thermal properties while minimizing the deleterious effect.

  9. Unique Challenges to (Federal) Enterprise Streaming

    NASA Technical Reports Server (NTRS)

    Walls, Bryan

    2006-01-01

    Enterprise streaming has different parameters than consumer Streaming. The government enterprise has some differences on top of that. I'd like to highlight some issues shared by the Federal government as a whole, with a closer look at streaming within NASA. Then we'll look at NASA's strategy for streaming.

  10. 29 CFR 779.21 - Enterprise.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Enterprise. 779.21 Section 779.21 Labor Regulations... OR SERVICES General Some Basic Definitions § 779.21 Enterprise. (a) Section 3(r) of the Act provides, in pertinent part that “enterprise” as used in the Act: means the related activities...

  11. Defining and Assessing Enterprise Capability in Schools

    ERIC Educational Resources Information Center

    Davies, Peter; Hughes, Amanda

    2015-01-01

    This paper describes the development of an instrument for assessing enterprise capability in schools. The approach to assessing enterprise capability builds on previous work by including three dimensions: self-efficacy, aspirations and knowledge and awareness. We find significant but weak associations between these three constructs suggesting that…

  12. 29 CFR 779.21 - Enterprise.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Enterprise. 779.21 Section 779.21 Labor Regulations... OR SERVICES General Some Basic Definitions § 779.21 Enterprise. (a) Section 3(r) of the Act provides, in pertinent part that “enterprise” as used in the Act: means the related activities...

  13. Enterprise Education: For All, or Just Some?

    ERIC Educational Resources Information Center

    Jones, Colin; Matlay, Harry; Maritz, Alex

    2012-01-01

    Purpose: The purpose of this paper is to provocatively enter four imagined worlds of enterprise education with the express aim of contemplating an emerging future. The authors do so not to expressly determine what positioning is most appropriate for enterprise/entrepreneurship education, but rather to consider the issues associated with each of…

  14. 29 CFR 779.21 - Enterprise.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Enterprise. 779.21 Section 779.21 Labor Regulations... OR SERVICES General Some Basic Definitions § 779.21 Enterprise. (a) Section 3(r) of the Act provides, in pertinent part that “enterprise” as used in the Act: means the related activities...

  15. 29 CFR 779.21 - Enterprise.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Enterprise. 779.21 Section 779.21 Labor Regulations... OR SERVICES General Some Basic Definitions § 779.21 Enterprise. (a) Section 3(r) of the Act provides, in pertinent part that “enterprise” as used in the Act: means the related activities...

  16. The Enterprise Campus at Midlands Technical College

    ERIC Educational Resources Information Center

    Rhames, Ronald L.; Ledbetter, J. Tom, Jr.

    2008-01-01

    The Commission established the Midlands Technical College (MTC) Enterprise Campus through special legislation. The Enterprise Campus provides for partnerships with private developers using private resources to create a unique business environment. Participants learn about the legislative process, the need for public/private partnerships, and what…

  17. 29 CFR 779.21 - Enterprise.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Enterprise. 779.21 Section 779.21 Labor Regulations... OR SERVICES General Some Basic Definitions § 779.21 Enterprise. (a) Section 3(r) of the Act provides, in pertinent part that “enterprise” as used in the Act: means the related activities...

  18. Enterprise Education: Revisiting Whitehead to Satisfy Gibbs

    ERIC Educational Resources Information Center

    Jones, Colin

    2006-01-01

    Purpose: This paper seeks to demonstrate that a truly learner-centered enterprise education programmer can be developed within a traditional business school environment. Design/methodology/approach: This paper unites the broad teaching philosophy of Alfred Whitehead with that of Allan Gibbs's enterprise specific teaching philosophies to consider…

  19. Stakeholder Analysis To Shape the Enterprise

    NASA Astrophysics Data System (ADS)

    McCaughin, Keith; Derosa, Joseph

    An enterprise is a complex adaptive social system that should maximize stakeholder, not shareholder, value — value to employees, customers, shareholders and others. We expand upon Russell Ackoff s direction to distribute value among stakeholders, to propose a schema of rules that guide the interactions among autonomous agents in the transactional environment of an enterprise. We define an enterprise as an organization and its transactional environment interacting with and adapting to each other. Enterprise behavior can only be understood in the context of this transactional environment where everything depends on everything else and interactions cannot be controlled, but can be influenced if they are guided by an understanding of the internal rules of the autonomous agents. The schema has four complementary rules (control, autonomy, return and value) derived from the work of Russell Ackoff and Michael Porter. The basic rules are applied in combination to eight stakeholder types derived from Richard Hopeman and Raymond McLeod (Leaders, Competitors, Customers, Public, Workers, Collaborators, Suppliers and Regulators). An enterprise can use this schema and rules in a process of stakeholder analysis to develop and continually refine strategies to encourage behaviors that benefit the enterprise and discourage behaviors that harm the enterprise. These strategies are implemented in a relationship management program in support of enterprise strategic management to consciously and explicitly shape the environment to reduce risks and increase opportunities for success.

  20. Enterprise Standard Industrial Classification Manual. 1974.

    ERIC Educational Resources Information Center

    Executive Office of the President, Washington, DC. Statistical Policy Div.

    This classification is presented to provide a standard for use with statistics about enterprises (i.e., companies, rather than their individual establishments) by kind of economic activity. The enterprise unit consists of all establishments under common direct or indirect ownership. It is defined to include all entities, including subsidiaries,…

  1. Fishing Facts Unlimited. Enterprise: Man & Technology.

    ERIC Educational Resources Information Center

    Southern Illinois Univ., Carbondale. Dept. of Technical and Industrial Education.

    Fishing Facts Unlimited, a student conducted enterprise in Technical and Industrial Education at Southern Illinois University, Carbondale has been a very successful operation, both financially and in providing a community service. The service provided by the enterprise was the production and sales of a 48-page fishing guide to Southern Illinois.…

  2. Embedding Enterprise in Science and Engineering Departments

    ERIC Educational Resources Information Center

    Handscombe, Robert D.; Rodriguez-Falcon, Elena; Patterson, Eann A.

    2008-01-01

    Purpose: This paper aims to focus on the attempts to implement the challenges of teaching enterprise to science and engineering students by the embedding approach chosen by the White Rose Centre for Enterprise (WRCE), one of the centres formed under the Science Engineering Challenge in the UK. Design/methodology/approach: WRCE's objective was to…

  3. Assessing Enterprise Capability: Guidance for Schools

    ERIC Educational Resources Information Center

    National Foundation for Educational Research, 2007

    2007-01-01

    This document offers guidance to schools on how assessment can support enterprise education. It presents the interim findings from research carried out by the National Foundation for Educational Research (NFER) for the Department for Education and Skills (DfES) in secondary schools in England. Enterprise capability is the key outcome of enterprise…

  4. New Management Practices and Enterprise Training.

    ERIC Educational Resources Information Center

    Smith, Andrew; Oczkowski, Eddie; Noble, Charles; Macklin, Robert

    The changing nature of the demand for training in Australian enterprises adopting new management practices and the implications of those changes for training providers were examined. More than 3,400 private sector enterprises were surveyed by mail, after which follow-up telephone interviews were conducted with 80 human resource practitioners from…

  5. Divergence in Male and Female Manipulative Behaviors with the Intensification of Metallurgy in Central Europe

    PubMed Central

    Macintosh, Alison A.; Pinhasi, Ron; Stock, Jay T.

    2014-01-01

    Humeral morphology has been shown to reflect, in part, habitual manipulative behaviors in humans. Among Central European agricultural populations, long-term social change, increasing task specialization, and technological innovation all had the potential to impact patterns of habitual activity and upper limb asymmetry. However, systematic temporal change in the skeletal morphology of agricultural populations in this region has not been well-characterized. This study investigates diachronic patterns in humeral biomechanical properties and lengths among 174 adult Central European agriculturalists through the first ∼5400 years of farming in the region. Greater asymmetry in biomechanical properties was expected to accompany the introduction of metallurgy, particularly in males, while upper limb loading patterns were expected to be more similar between the Bronze and Iron Ages. Results revealed a divergence in the lateralization of upper limb biomechanical properties by sex between the Early/Middle Neolithic and Early/Middle Bronze Age. Neolithic females had significantly more variable properties than males in both humeri, while Bronze Age female properties became homogeneous and very symmetrical relative to the right-biased lateralization of contemporaneous males. The Bronze Age to Iron Age transition was associated with morphological change among females, with a significant increase in right-biased asymmetry and a concomitant reduction in sexual dimorphism. Relative to biomechanical properties, humeral length variation and asymmetry were low though some significant sexual dimorphism and temporal change was found. It was among females that the lateralization of humeral biomechanical properties, and variation within them, changed most profoundly through time. This suggests that the introduction of the ard and plow, metallurgical innovation, task specialization, and socioeconomic change through ∼5400 years of agriculture impacted upper limb loading in Central

  6. Liquid Phase Sintering of Boron-Containing Powder Metallurgy Steel with Chromium and Carbon

    NASA Astrophysics Data System (ADS)

    Wu, Ming-Wei; Fan, Yu-Chi; Huang, Her-Yueh; Cai, Wen-Zhang

    2015-11-01

    Liquid phase sintering is an effective method to improve the densification of powder metallurgy materials. Boron is an excellent alloying element for liquid phase sintering of Fe-based materials. However, the roles of chromium and carbon, and particularly that of the former, on liquid phase sintering are still undetermined. This study demonstrated the effects of chromium and carbon on the microstructure, elemental distribution, boride structure, liquid formation, and densification of Fe-B-Cr and Fe-B-Cr-C steels during liquid phase sintering. The results showed that steels with 0.5 wt pct C densify faster than those without 0.5 wt pct C. Moreover, although only one liquid phase forms in Fe-B-Cr steel, adding 0.5 wt pct C reduces the formation temperature of the liquid phase by about 50 K (°C) and facilitates the formation of an additional liquid, resulting in better densification at 1473 K (1200 °C). In both Fe-B-Cr and Fe-B-Cr-C steels, increasing the chromium content from 1.5 to 3 wt pct raises the temperature of liquid formation by about 10 K (°C). Thermodynamic simulations and experimental results demonstrated that carbon atoms dissolved in austenite facilitate the eutectic reaction and reduce the formation temperature of the liquid phase. In contrast, both chromium and molybdenum atoms dissolved in austenite delay the eutectic reaction. Furthermore, the 3Cr-0.5Mo additive in the Fe-0.4B steel does not change the typical boride structure of M2B. With the addition of 0.5 wt pct C, the crystal structure is completely transformed from M2B boride to M3(B,C) boro-carbide.

  7. In vitro degradation and cytotoxicity of Mg/Ca composites produced by powder metallurgy.

    PubMed

    Zheng, Y F; Gu, X N; Xi, Y L; Chai, D L

    2010-05-01

    Mg/Ca (1 wt.%, 5 wt.%, 10 wt.% Ca) composites were prepared from pure magnesium and calcium powders using the powder metallurgy method, aiming to enlarge the addition of Ca content without the formation of Mg(2)Ca. The microstructures, mechanical properties and cytotoxicities of Mg/Ca composite samples were investigated. The corrosion of Mg/Ca composites in Dulbecco's modified Eagle's medium (DMEM) for various immersion intervals was studied by electrochemical impedance spectroscopy measurements and environmental scanning electron microscope, with the concentrations of released Mg and Ca ions in DMEM for various immersion time intervals being measured. It was shown that the main constitutional phases were Mg and Ca, which were uniformly distributed in the Mg matrix. The ultimate tensile strength (UTS) and elongation of experimental composites decreased with increasing Ca content, and the UTS of Mg/1Ca composite was comparable with that of as-extruded Mg-1Ca alloy. The corrosion potential increased with increasing Ca content, whereas the current density and the impedance decreased. It was found that the protective surface film formed quickly at the initial immersion stage. With increasing immersion time, the surface film became compact, and the corrosion rate of Mg/Ca composites slowed down. The surface film consisted mainly of CaCO(3), MgCO(3)x3H(2)O, HA and Mg(OH)(2) after 72 h immersion in DMEM. Mg/1Ca and Mg/5Ca composite extracts had no significant toxicity (p>0.05) to L-929 cells, whereas Mg/10Ca composite extract induced approximately 40% reduced cell viability. PMID:19815098

  8. Divergence in male and female manipulative behaviors with the intensification of metallurgy in Central Europe.

    PubMed

    Macintosh, Alison A; Pinhasi, Ron; Stock, Jay T

    2014-01-01

    Humeral morphology has been shown to reflect, in part, habitual manipulative behaviors in humans. Among Central European agricultural populations, long-term social change, increasing task specialization, and technological innovation all had the potential to impact patterns of habitual activity and upper limb asymmetry. However, systematic temporal change in the skeletal morphology of agricultural populations in this region has not been well-characterized. This study investigates diachronic patterns in humeral biomechanical properties and lengths among 174 adult Central European agriculturalists through the first ∼ 5400 years of farming in the region. Greater asymmetry in biomechanical properties was expected to accompany the introduction of metallurgy, particularly in males, while upper limb loading patterns were expected to be more similar between the Bronze and Iron Ages. Results revealed a divergence in the lateralization of upper limb biomechanical properties by sex between the Early/Middle Neolithic and Early/Middle Bronze Age. Neolithic females had significantly more variable properties than males in both humeri, while Bronze Age female properties became homogeneous and very symmetrical relative to the right-biased lateralization of contemporaneous males. The Bronze Age to Iron Age transition was associated with morphological change among females, with a significant increase in right-biased asymmetry and a concomitant reduction in sexual dimorphism. Relative to biomechanical properties, humeral length variation and asymmetry were low though some significant sexual dimorphism and temporal change was found. It was among females that the lateralization of humeral biomechanical properties, and variation within them, changed most profoundly through time. This suggests that the introduction of the ard and plow, metallurgical innovation, task specialization, and socioeconomic change through ∼ 5400 years of agriculture impacted upper limb loading in Central

  9. Interfacial reactions and wetting in Al-Mg sintered by powder metallurgy process

    NASA Astrophysics Data System (ADS)

    Faisal, Heny; Darminto, Triwikantoro, Zainuri, M.

    2016-04-01

    Was conducted to analyze the effect of temperature variation on the bonding interface sintered composite Al-Mg and analyze the effect of variations of the density and hardness sinter. Research carried out by the base material powders of Al, Mg powder and solvent n-butanol. The method used in this study is a powder metallurgy, with a composition of 60% volume fraction of Al - 40% Mg. Al-Mg mixing with n-butanol for 1 hour at 500 rpm. Then the emphasis (cold comression) with a size of 1.4 cm in diameter dies and height of 2.8 cm, is pressed with a force of 20 MPa and held for 15 minutes. After the sample into pellets, then sintered at various temperatures 300 °C, 350 °C, 400 °C and 450 °C. Characterization is done by using the testing green density, sintered density, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), vickers microhardness, and press test. XRD data analysis done by using X'Pert High Score Plus (HSP) to determine whether there is a new phase is formed. Test results show that the sintered density increasing sintering temperature, the resulting density is also increasing (shrinkage). However, at a temperature of 450 °C decreased (swelling). With the increased sinter density, interfacial bonding getting Kuta and more compact so that its hardness is also increased. From the test results of SEM / EDX, there Mg into Al in the border area. At temperatures of 300 °C, 350 °C, 400 °C, the phase formed is Al, Mg and MgO. While phase is formed at a temperature of 450 °C is aluminum magnesium (Al3Mg2), Aluminum Magnesium Zinc (AlMg2Zn).

  10. Effects of porosity on corrosion resistance of Mg alloy foam produced by powder metallurgy technology

    SciTech Connect

    Aghion, E. Perez, Y.

    2014-10-15

    Magnesium alloy foams have the potential to serve as structural material for regular light-weight applications as well as for biodegradable scaffold implants. However, their main disadvantage relates to the high reactivity of magnesium and consequently their natural tendency to corrode in regular service conditions and in physiological environments. The present study aims at evaluating the effect of porosity on the corrosion resistance of MRI 201S magnesium alloy foams in 0.9% NaCl solution and in phosphate buffer saline solution as a simulated physiological electrolyte. The magnesium foams were produced by powder metallurgy technology using space-holding particles to control the porosity content. Machined chips were used as raw material for the production of Mg alloy powder by milling process. The microstructure of the foams was examined using optical and scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analysis. The corrosion behavior was evaluated by immersion test and potentiodynamic polarization analysis. The results obtained clearly demonstrate that the porosity has a significant effect on the corrosion resistance of the tested foams. Foams with 14–19% porosity have a corrosion rate of 4–10 mcd and 7–15 mcd in NaCl and phosphate buffer saline solution, respectively, compared to only 0.10 mcd for the same alloy in as cast conditions. This increased corrosion degradation of the Mg foams by more than one order of magnitude compared to the cast alloy may limit their potential application in regular and physiological environments. - Highlights: • Porosity has a detrimental effect on corrosion resistance of MRI 201S Mg foams. • 14–19% porosity increases the corrosion rate by more than one order of magnitude. • Accelerated corrosion limits the use of foams in regular/physiological environments.