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Sample records for aged plutonium alloys

  1. Spiked Alloy Production for Accelerated Aging of Plutonium

    SciTech Connect

    Wilk, P A; McNeese, J A; Dodson, K E; Williams, W L; Krikorian, O H; Blau, M S; Schmitz, J E; Bajao, F G; Mew, D A; Matz, T E; Torres, R A; Holck, D M; Moody, K J; Kenneally, J M

    2009-07-10

    The accelerated aging effects on weapons grade plutonium alloys are being studied using {sup 238}Pu-enriched plutonium metal to increase the rate of formation of defect structures. Pyrochemical processing methods have been used to produce two {sup 238}Pu-spiked plutonium alloys with nominal compositions of 7.5 wt% {sup 238}Pu. Processes used in the preparation of the alloys include direct oxide reduction of PuO{sub 2} with calcium and electrorefining. Rolled disks were prepared from the spiked alloys for sampling. Test specimens were cut out of the disks for physical property measurements.

  2. PLUTONIUM ALLOYS

    DOEpatents

    Chynoweth, W.

    1959-06-16

    The preparation of low-melting-point plutonium alloys is described. In a MgO crucible Pu is placed on top of the lighter alloying metal (Fe, Co, or Ni) and the temperature raised to 1000 or 1200 deg C. Upon cooling, the alloy slug is broke out of the crucible. With 14 at. % Ni the m.p. is 465 deg C; with 9.5 at. % Fe the m.p. is 410 deg C; and with 12.0 at. % Co the m.p. is 405 deg C. (T.R.H.) l6262 l6263 ((((((((Abstract unscannable))))))))

  3. Plutonium aging

    SciTech Connect

    Olivas, J.D.

    1999-03-01

    The author describes the plutonium aging program at the Los Alamos National Laboratory. The aging of plutonium components in the US nuclear weapons stockpile has become a concern due to several events: the end of the cold war, the cessation of full scale underground nuclear testing as a result of the Comprehensive Test Ban Treaty (CTBT) and the closure of the Rocky Flats Plant--the site where the plutonium components were manufactured. As a result, service lifetimes for nuclear weapons have been lengthened. Dr. Olivas will present a brief primer on the metallurgy of plutonium, and will then describe the technical approach to ascertaining the long-term changes that may be attributable to self-radiation damage. Facilities and experimental techniques which are in use to study aging will be described. Some preliminary results will also be presented.

  4. PLUTONIUM-THORIUM ALLOYS

    DOEpatents

    Schonfeld, F.W.

    1959-09-15

    New plutonium-base binary alloys useful as liquid reactor fuel are described. The alloys consist of 50 to 98 at.% thorium with the remainder plutonium. The stated advantages of these alloys over unalloyed plutonium for reactor fuel use are easy fabrication, phase stability, and the accompanying advantuge of providing a means for converting Th/sup 232/ into U/sup 233/.

  5. DELTA PHASE PLUTONIUM ALLOYS

    DOEpatents

    Cramer, E.M.; Ellinger, F.H.; Land. C.C.

    1960-03-22

    Delta-phase plutonium alloys were developed suitable for use as reactor fuels. The alloys consist of from 1 to 4 at.% zinc and the balance plutonium. The alloys have good neutronic, corrosion, and fabrication characteristics snd possess good dimensional characteristics throughout an operating temperature range from 300 to 490 deg C.

  6. PLUTONIUM-ZIRCONIUM ALLOYS

    DOEpatents

    Schonfeld, F.W.; Waber, J.T.

    1960-08-30

    A series of nuclear reactor fuel alloys consisting of from about 5 to about 50 at.% zirconium (or higher zirconium alloys such as Zircaloy), balance plutonium, and having the structural composition of a plutonium are described. Zirconium is a satisfactory diluent because it alloys readily with plutonium and has desirable nuclear properties. Additional advantages are corrosion resistance, excellent fabrication propenties, an isotropie structure, and initial softness.

  7. PLUTONIUM-CERIUM ALLOY

    DOEpatents

    Coffinberry, A.S.

    1959-01-01

    An alloy is presented for use as a reactor fuel. The binary alloy consists essentially of from about 5 to 90 atomic per cent cerium and the balance being plutonium. A complete phase diagram for the cerium--plutonium system is given.

  8. PLUTONIUM-URANIUM ALLOY

    DOEpatents

    Coffinberry, A.S.; Schonfeld, F.W.

    1959-09-01

    Pu-U-Fe and Pu-U-Co alloys suitable for use as fuel elements tn fast breeder reactors are described. The advantages of these alloys are ease of fabrication without microcracks, good corrosion restatance, and good resistance to radiation damage. These advantages are secured by limitation of the zeta phase of plutonium in favor of a tetragonal crystal structure of the U/sub 6/Mn type.

  9. PLUTONIUM-URANIUM-TITANIUM ALLOYS

    DOEpatents

    Coffinberry, A.S.

    1959-07-28

    A plutonium-uranium alloy suitable for use as the fuel element in a fast breeder reactor is described. The alloy contains from 15 to 60 at.% titanium with the remainder uranium and plutonium in a specific ratio, thereby limiting the undesirable zeta phase and rendering the alloy relatively resistant to corrosion and giving it the essential characteristic of good mechanical workability.

  10. PLUTONIUM-CERIUM-COPPER ALLOYS

    DOEpatents

    Coffinberry, A.S.

    1959-05-12

    A low melting point plutonium alloy useful as fuel is a homogeneous liquid metal fueled nuclear reactor is described. Vessels of tungsten or tantalum are useful to contain the alloy which consists essentially of from 10 to 30 atomic per cent copper and the balance plutonium and cerium. with the plutontum not in excess of 50 atomic per cent.

  11. TERNARY ALLOY-CONTAINING PLUTONIUM

    DOEpatents

    Waber, J.T.

    1960-02-23

    Ternary alloys of uranium and plutonium containing as the third element either molybdenum or zirconium are reported. Such alloys are particularly useful as reactor fuels in fast breeder reactors. The alloy contains from 2 to 25 at.% of molybdenum or zirconium, the balance being a combination of uranium and plutonium in the ratio of from 1 to 9 atoms of uranlum for each atom of plutonium. These alloys are prepared by melting the constituent elements, treating them at an elevated temperature for homogenization, and cooling them to room temperature, the rate of cooling varying with the oomposition and the desired phase structure. The preferred embodiment contains 12 to 25 at.% of molybdenum and is treated by quenching to obtain a body centered cubic crystal structure. The most important advantage of these alloys over prior binary alloys of both plutonium and uranium is the lack of cracking during casting and their ready machinability.

  12. PLUTONIUM-CERIUM-COBALT AND PLUTONIUM-CERIUM-NICKEL ALLOYS

    DOEpatents

    Coffinberry, A.S.

    1959-08-25

    >New plutonium-base teroary alloys useful as liquid reactor fuels are described. The alloys consist of 10 to 20 atomic percent cobalt with the remainder plutonium and cerium in any desired proportion, with the plutonium not in excess of 88 atomic percent; or, of from 10 to 25 atomic percent nickel (or mixture of nickel and cobalt) with the remainder plutonium and cerium in any desired proportion, with the plutonium not in excess of 86 atomic percent. The stated advantages of these alloys over unalloyed plutonium for reactor fuel use are a lower melting point and a wide range of permissible plutonium dilution.

  13. Plutonium age dating reloaded

    NASA Astrophysics Data System (ADS)

    Sturm, Monika; Richter, Stephan; Aregbe, Yetunde; Wellum, Roger; Mayer, Klaus; Prohaska, Thomas

    2014-05-01

    Although the age determination of plutonium is and has been a pillar of nuclear forensic investigations for many years, additional research in the field of plutonium age dating is still needed and leads to new insights as the present work shows: Plutonium is commonly dated with the help of the 241Pu/241Am chronometer using gamma spectrometry; in fewer cases the 240Pu/236U chronometer has been used. The age dating results of the 239Pu/235U chronometer and the 238Pu/234U chronometer are scarcely applied in addition to the 240Pu/236U chronometer, although their results can be obtained simultaneously from the same mass spectrometric experiments as the age dating result of latter. The reliability of the result can be tested when the results of different chronometers are compared. The 242Pu/238U chronometer is normally not evaluated at all due to its sensitivity to contamination with natural uranium. This apparent 'weakness' that renders the age dating results of the 242Pu/238U chronometer almost useless for nuclear forensic investigations, however turns out to be an advantage looked at from another perspective: the 242Pu/238U chronometer can be utilized as an indicator for uranium contamination of plutonium samples and even help to identify the nature of this contamination. To illustrate this the age dating results of all four Pu/U clocks mentioned above are discussed for one plutonium sample (NBS 946) that shows no signs of uranium contamination and for three additional plutonium samples. In case the 242Pu/238U chronometer results in an older 'age' than the other Pu/U chronometers, contamination with either a small amount of enriched or with natural or depleted uranium is for example possible. If the age dating result of the 239Pu/235U chronometer is also influenced the nature of the contamination can be identified; enriched uranium is in this latter case a likely cause for the missmatch of the age dating results of the Pu/U chronometers.

  14. METHOD FOR OBTAINING PLUTONIUM METAL AND ALLOYS OF PLUTONIUM FROM PLUTONIUM TRICHLORIDE

    DOEpatents

    Reavis, J.G.; Leary, J.A.; Maraman, W.J.

    1962-11-13

    A process is given for both reducing plutonium trichloride to plutonium metal using cerium as the reductant and simultaneously alloying such plutonium metal with an excess of cerium or cerium and cobalt sufficient to yield the desired nuclear reactor fuel composition. The process is conducted at a temperature from about 550 to 775 deg C, at atmospheric pressure, without the use of booster reactants, and a substantial decontamination is effected in the product alloy of any rare earths which may be associated with the source of the plutonium. (AEC)

  15. Effects of self-irradiation in plutonium alloys

    DOE PAGESBeta

    Chung, B. W.; Lema, K. E.; Allen, P. G.

    2015-09-16

    In this paper, we present updated results of self-irradiation effects on 238Pu-enriched 239Pu alloys measured by immersion density, dilatometry, and tensile tests. We obtained the self-irradiation equivalent time of nearly 200 years, nearly 100 years longer than in our previous papers. At this extended aging, we find the rate of decrease in density has slowed significantly, stabilizing around 15.73 g/cc, without signs of void swelling. The volume expansion measured at 35°C also shows apparent saturation at less than 0.25%. Quasi-static tensile measurement still show gradual increase in the strength of plutonium alloys with age.

  16. Real-time monitoring of plutonium content in uranium-plutonium alloys

    SciTech Connect

    Li, Shelly Xiaowei; Westphal, Brian Robert; Herrmann, Steven Douglas

    2015-09-01

    A method and device for the real-time, in-situ monitoring of Plutonium content in U--Pu Alloys comprising providing a crucible. The crucible has an interior non-reactive to a metallic U--Pu alloy within said interior of said crucible. The U--Pu alloy comprises metallic uranium and plutonium. The U--Pu alloy is heated to a liquid in an inert or reducing atmosphere. The heated U--Pu alloy is then cooled to a solid in an inert or reducing atmosphere. As the U--Pu alloy is cooled, the temperature of the U--Pu alloy is monitored. A solidification temperature signature is determined from the monitored temperature of the U--Pu alloy during the step of cooling. The amount of Uranium and the amount of Plutonium in the U--Pu alloy is then determined from the determined solidification temperature signature.

  17. Transmission Electron Microscopy Characterization of Helium Bubbles in Aged Plutonium

    SciTech Connect

    Schwartz, A J; Wall, M A; Zocco, T G; Blobaum, K M

    2004-11-02

    The self-irradiation damage generated by alpha decay of plutonium results in the formation of lattice defects, helium, and uranium atoms. Over time, microstructural evolution resulting from the self-irradiation may influence the physical and mechanical properties of the material. In order to assess microstructural changes, we have developed and applied procedures for the specimen preparation, handling, and transmission electron microscopy characterization of Pu alloys. These transmission electron microscopy investigations of Pu-Ga alloys ranging in age up to 42-years old reveal the presence of nanometer-sized helium bubbles. The number density of bubbles and the average size have been determined for eight different aged materials.

  18. PLUTONIUM ALLOYS CONTAINING CONTROLLED AMOUNTS OF PLUTONIUM ALLOTROPES OBTAINED BY APPLICATION OF HIGH PRESSURES

    DOEpatents

    Elliott, R.O.; Gschneidner, K.A. Jr.

    1962-07-10

    A method of making stabilized plutonium alloys which are free of voids and cracks and have a controlled amount of plutonium allotropes is described. The steps include adding at least 4.5 at.% of hafnium, indium, or erbium to the melted plutonium metal, homogenizing the resulting alloy at a temperature of 450 deg C, cooling to room temperature, and subjecting the alloy to a pressure which produces a rapid increase in density with a negligible increase in pressure. The pressure required to cause this rapid change in density or transformation ranges from about 800 to 2400 atmospheres, and is dependent on the alloying element. (AEC)

  19. Effects of self-irradiation in plutonium alloys

    NASA Astrophysics Data System (ADS)

    Chung, B. W.; Lema, K. E.; Allen, P. G.

    2016-04-01

    In this paper, we present updated results of self-irradiation effects on 238Pu-enriched 239Pu alloys measured by immersion density, dilatometry, and tensile tests. We obtained the self-irradiation equivalent time of nearly 200 years, nearly 100 years longer than in our previous papers. At this extended aging, we find the rate of decrease in density has slowed significantly, stabilizing around 15.73 g/cc, without signs of void swelling. The volume expansion measured at 35 °C also shows apparent saturation at less than 0.25%. Quasi-static tensile measurement still show gradual increase in the strength of plutonium alloys with age.

  20. Effects of self-irradiation in plutonium alloys

    SciTech Connect

    Chung, B. W.; Lema, K. E.; Allen, P. G.

    2015-09-16

    In this paper, we present updated results of self-irradiation effects on 238Pu-enriched 239Pu alloys measured by immersion density, dilatometry, and tensile tests. We obtained the self-irradiation equivalent time of nearly 200 years, nearly 100 years longer than in our previous papers. At this extended aging, we find the rate of decrease in density has slowed significantly, stabilizing around 15.73 g/cc, without signs of void swelling. The volume expansion measured at 35°C also shows apparent saturation at less than 0.25%. Quasi-static tensile measurement still show gradual increase in the strength of plutonium alloys with age.

  1. Overview of Modeling and Simulations of Plutonium Aging

    SciTech Connect

    Schwartz, A J; Wolfer, W G

    2007-04-24

    Computer-aided materials research is now an integral part of science and technology. It becomes particularly valuable when comprehensive experimental investigations and materials testing are too costly, hazardous, or of excessive duration; then, theoretical and computational studies can supplement and enhance the information gained from limited experimental data. Such is the case for improving our fundamental understanding of the properties of aging plutonium in the nuclear weapons stockpile. The question of the effects of plutonium aging on the safety, security, and reliability of the nuclear weapons stockpile emerged after the United States closed its plutonium manufacturing facility in 1989 and decided to suspend any further underground testing of nuclear weapons in 1992. To address this, the Department of Energy's National Nuclear Security Administration (NNSA) initiated a research program to investigate plutonium aging, i.e., the changes with time of properties of Pu-Ga alloys employed in the nuclear weapons and to develop models describing these changes sufficiently reliable to forecast them for several decades. The November 26, 2006 press release by the NNSA summarizes the conclusions of the investigation, '...there appear to be no serious or sudden changes occurring, or expected to occur, in plutonium that would affect performance of pits beyond the well-understood, gradual degradation of plutonium materials'. Furthermore, 'These studies show that the degradation of plutonium in our nuclear weapons will not affect warhead reliability for decades', then NNSA Administrator Linton Brooks said. 'It is now clear that although plutonium aging contributes, other factors control the overall life expectancy of nuclear weapons systems'. The origin of plutonium aging is the natural decay of certain plutonium isotopes. Specifically, it is the process of alpha decay in which a plutonium atom spontaneously splits into a 5 MeV alpha particle and an 85keV uranium recoil

  2. Plutonium microstructures. Part 2. Binary and ternary alloys

    SciTech Connect

    Cramer, E.M.; Bergin, J.B.

    1983-12-01

    This report is the second of three parts that exhibit illustrations of inclusions in plutonium metal from inherent and tramp impurities, of intermetallic and nonmetallic constituents from alloy additions, and of the effects of thermal and mechanical treatments. This part includes illustrations of the microstructures in binary cast alloys and a few selected ternary alloys that result from measured additions of diluent elements, and of the microconstituents that are characteristic of phase fields in extended alloy systems. Microhardness data are given and the etchant used in the preparation of each sample is described.

  3. Plutonium and americium recovery from spent molten-salt-extraction salts with aluminum-magnesium alloys

    SciTech Connect

    Cusick, M.J.; Sherwood, W.G.; Fitzpatrick, R.F.

    1984-04-23

    Development work was performed to determine the feasibility of removing plutonium and americium from spent molten-salt-extraction (MSE) salts using Al-Mg alloys. If the product buttons from this process are compatible with subsequent aqueous processing, the complex chloride-to-nitrate aqueous conversion step which is presently required for these salts may be eliminated. The optimum alloy composition used to treat spent 8 wt % MSE salts in the past yielded poor phase-disengagement characteristics when applied to 30 mol % salts. After a limited investigation of other alloy compositions in the Al-Mg-Pu-Am system, it was determined that the Al-Pu-Am system could yield a compatible alloy. In this system, experiments were performed to investigate the effects of plutonium loading in the alloy, excess magnesium, age of the spent salt on actinide recovery, phase disengagement, and button homogeneity. Experimental results indicate that 95 percent plutonium recoveries can be attained for fresh salts. Further development is required for backlog salts generated prior to 1981. A homogeneous product alloy, as required for aqueous processing, could not be produced.

  4. Thermodynamics and Structure of Plutonium Alloys

    SciTech Connect

    Allen, P G; Turchi, P A; Gallegos, G F

    2004-01-30

    The goal of this project was to investigate the chemical and structural effects of gallium and impurity elements, iron and nickel, on the phase behavior and crystallography of Pu-Ga alloys. This was done utilizing a theoretical chemical approach to predict binary and ternary alloy energetics, phase stability, and transformations. The modeling results were validated with experimental data derived from the synthesis of selected alloys and advanced characterization tools. The ultimate goal of this work was to develop a robust predictive capability for studying the thermodynamics and the structure-properties relationships in complex materials of high relevance to the Laboratory and DOE mission.

  5. Distillation of cadmium from uranium plutonium cadmium alloy

    NASA Astrophysics Data System (ADS)

    Kato, Tetsuya; Iizuka, Masatoshi; Inoue, Tadashi; Iwai, Takashi; Arai, Yasuo

    2005-04-01

    Uranium-plutonium alloy was prepared by distillation of cadmium from U-Pu-Cd ternary alloy. The initial ternary alloy contained 2.9 wt% U and 8.7 wt% Pu other than Cd, which were recovered by molten salt electrolysis with liquid Cd cathode. The distillation experiments were conducted in 10 g scale of the initial alloy using a small-scale distillation furnace equipped with an evaporator and a condenser in a vacuum vessel. After distillation at 1073 K, the weight of the residue was in good agreement with that of the loaded actinides, where the content of Cd decreased to less than 0.05 wt%. The uranium-plutonium alloy product was recovered without adhering to the yttria crucible. The cross section of the product was observed using electron probe micro-analyzer and it was found to consist of a dense material. Almost all of the evaporated Cd was recovered in the condenser and so enclosed well in the apparatus.

  6. The solubility of hydrogen and deuterium in alloyed, unalloyed and impure plutonium metal

    SciTech Connect

    Richmond, Scott; Bridgewater, Jon S; Ward, John W; Allen, Thomas A

    2009-01-01

    Pressure-Composition-Temperature (PCT) data are presented for the plutonium-hydrogen (Pu-H) and plutonium-deuterium (Pu-D) systems in the solubility region up to terminal solubility (precipitation of PuH{sub 2}). The heats of solution for PuH{sub s} and PuD{sub s} are determined from PCT data in the ranges 350-625 C for gallium alloyed Pu and 400-575 C for unalloyed Pu. The solubility of high purity plutonium alloyed with 2 at.% gallium is compared to high purity unalloyed plutonium. Significant differences are found in hydrogen solubility for unalloyed Pu versus gallium alloyed Pu. Differences in hydrogen solubility due to an apparent phase change are observable in the alloyed and unalloyed solubilities. The effect of iron impurities on Pu-Ga alloyed Pu is shown via hydrogen solubility data as preventing complete homogenization.

  7. In situ purification, alloying and casting methodology for metallic plutonium

    NASA Astrophysics Data System (ADS)

    Lashley, Jason C.; Blau, Michael S.; Staudhammer, Karl P.; Pereyra, Ramiro A.

    Plutonium metal that has been double ER (electrorefined/electrorefining) was further purified via zone refining, using a floating molten zone to minimize the introduction of impurities. The temperature of the molten zone was 750°C, and the atmosphere was 10 -5 Pa. A total of ten zone refining passes were made at a travel rate of 1.5 cm/h. There were 19 elements reduced to quantities below the minimum detectable limits (MDL) by zone refining, while P, K, and W were significantly reduced. The zone-refined metal was then used in an in situ distillation, alloying, and casting step to prepare tapered specimens for single-crystal growth experiments. Specifically, 241Am was distilled from Pu metal by levitating Pu metal with 1 wt% Ga in the melt in a Crystallox vertical electromagnetic levitation crucible at 10 -5 Pa. The Pu is alloyed with Ga to stabilize the δ phase (fcc symmetry) upon solidification. The Pu was chill-cast directly from the electromagnetic levitation field into 1- cm tapered specimens. A water-cooled ceramic mold was used, and the Pu metal was cooled at a rate of 100°C/min. A microstructure examination of the specimen showed 10 × 25 μm acicular grains with a density of 15.938 g/cm 3 (±0.002 g/cm 3).

  8. Plutonium: Aging mechanisms and weapon pit lifetime assessment

    NASA Astrophysics Data System (ADS)

    Martz, Joseph C.; Schwartz, Adam J.

    2003-09-01

    Planning for future refurbishment and manufacturing needs of the U.S. nuclear weapons complex critically depends on credible estimates for component lifetimes. One of the most important of these components is the pit, that portion of the weapon that contains the fissile element plutonium. The U.S. government has proposed construction of a new Modern Pit Facility, and a key variable in planning both the size and schedule for this facility is the minimum estimated lifetime for stockpile pits. This article describes the current understanding of aging effects in plutonium, provides a lifetime estimate range, and outlines in some detail methodology that will improve this estimate over the next few years.

  9. Age determination of single plutonium particles after chemical separation

    NASA Astrophysics Data System (ADS)

    Shinonaga, T.; Donohue, D.; Ciurapinski, A.; Klose, D.

    2009-01-01

    Age determination of single plutonium particles was demonstrated using five particles of the standard reference material, NBS 947 (Plutonium Isotopic Standard. National Bureau of Standards, Washington, D.C. 20234, August 19, 1982, currently distributed as NBL CRM-137) and the radioactive decay of 241Pu into 241Am. The elemental ratio of Am/Pu in Pu particles found on a carbon planchet was measured by wavelength dispersive X-ray spectrometry (WDX) coupled to a scanning electron microscope (SEM). After the WDX measurement, each plutonium particle, with an average size of a few μm, was picked up and relocated to a silicon wafer inside the SEM chamber using a micromanipulator. The silicon wafer was then transferred to a quartz tube for dissolution in an acid solution prior to chemical separation. After the Pu was chemically separated from Am and U, the isotopic ratios of Pu ( 240Pu/ 239Pu, 241Pu/ 239Pu and 242Pu/ 239Pu) were measured with a thermal ionization mass spectrometer (TIMS) for the calculation of Pu age. The age of particles determined in this study was in good agreement with the expected age (35.9 a) of NBS 947 within the measurement uncertainty.

  10. Experimental validation of plutonium ageing by Monte Carlo correlated sampling

    SciTech Connect

    Litaize, O.; Bernard, D.; Santamarina, A.

    2006-07-01

    Integral measurements of Plutonium Ageing were performed in two homogeneous MOX cores (MISTRAL2 and MISTRALS) of the French MISTRAL Programme between 1996 and year 2000. The analysis of the MISTRAL2 experiment with JEF-2.2 nuclear data library high-lightened an underestimation of {sup 241}Am capture cross section. The next experiment (MISTRALS) did not conclude in the same way. This paper present a new analysis performed with the recent JEFF-3.1 library and a Monte Carlo perturbation method (correlated sampling) available in the French TRIPOLI4 code. (authors)

  11. Properties of plutonium and its alloys for use as fast reactor fuels

    NASA Astrophysics Data System (ADS)

    Hecker, Siegfried S.; Stan, Marius

    2008-12-01

    Early interest in metallic plutonium fuels for fast reactors led to much research on plutonium alloy systems including binary solid solutions with the addition of aluminum, gallium, or zirconium and low melting eutectic alloys with iron and nickel or cobalt. There was also interest in ternaries of these elements with plutonium and cerium. The solid solution and eutectic alloys have most unusual properties, including negative thermal expansion in some solid-solution alloys and the highest viscosity known for liquid metals in the Pu-Fe system. Although metallic fuels have many potential advantages over ceramic fuels, the early attempts were unsuccessful because these fuels suffered from high swelling rates during burn up and high smearing densities. The liquid metal fuels experienced excessive corrosion. Subsequent work on higher melting U-Pu-Zr metallic fuels was much more promising. In light of the recent rebirth of interest in fast reactors, we review some of the key properties of the early fuels and discuss the challenges presented by the ternary alloys.

  12. METHOD OF MAKING ALLOYS OF BERYLLIUM WITH PLUTONIUM AND THE LIKE

    DOEpatents

    Runnals, O.J.C.

    1959-02-24

    The production of alloys of beryllium with one or more of the metals uranium, plutonium, actinium, americium, curium, thorium, and cerium are described. A halide salt of the metal to be alloyed with the beryllium is heated at 1300 deg C in the presence of beryllium to reduce the halide to metal and cause the latter to alloy directly with the beryllium. Although the heavy metal halides are more stable, thermodynamically, than the beryllium halides, the reducing reaction proceeds to completion if the beryllium halide product is continuously removed by vacuum distillation.

  13. Method of making alloys of beryllium with plutonium and the like

    DOEpatents

    Runnals, O J.C.

    1959-02-24

    The production or alloys of beryllium with one or more of the metals uranium, plutonium, actinium, americium, curium, thorium, and cerium is described. A halide salt or the metal to be alloyed with the beryllium is heated at l3O0 deg C in the presence of beryllium to reduce the halide to metal and cause the latter to alloy directly with the beryllium. Although the heavy metal halides are more stable, thermodynamically, than the beryllium halides, the reducing reaction proceeds to completion if the beryllium halide product is continuously removed by vacuum distillation.

  14. Plutonium

    NASA Astrophysics Data System (ADS)

    Clark, David L.; Hecker, Siegfried S.; Jarvinen, Gordon D.; Neu, Mary P.

    The element plutonium occupies a unique place in the history of chemistry, physics, technology, and international relations. After the initial discovery based on submicrogram amounts, it is now generated by transmutation of uranium in nuclear reactors on a large scale, and has been separated in ton quantities in large industrial facilities. The intense interest in plutonium resulted fromthe dual-use scenario of domestic power production and nuclear weapons - drawing energy from an atomic nucleus that can produce a factor of millions in energy output relative to chemical energy sources. Indeed, within 5 years of its original synthesis, the primary use of plutonium was for the release of nuclear energy in weapons of unprecedented power, and it seemed that the new element might lead the human race to the brink of self-annihilation. Instead, it has forced the human race to govern itself without resorting to nuclear war over the past 60 years. Plutonium evokes the entire gamut of human emotions, from good to evil, from hope to despair, from the salvation of humanity to its utter destruction. There is no other element in the periodic table that has had such a profound impact on the consciousness of mankind.

  15. Thermal aging effects in refractory metal alloys

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.

    1986-01-01

    The alloys of niobium and tantalum are attractive from a strength and compatibility viewpoint for high operating temperatures required in materials for fuel cladding, liquid metal transfer, and heat pipe applications in space power systems that will supply from 100 kWe to multi-megawatts for advanced space systems. To meet the system requirements, operating temperatures ranging from 1100 to 1600 K have been proposed. Expected lives of these space power systems are from 7 to 10 yr. A program is conducted at NASA Lewis to determine the effects of long-term, high-temperature exposure on the microstructural stability of several commercial tantalum and niobium alloys. Variables studied in the investigation include alloy composition, pre-age annealing temperature, aging time, temperature, and environment (lithium or vacuum), welding, and hydrogen doping. Alloys are investigated by means of cryogenic bend tests and tensile tests. Results show that the combination of tungsten and hafnium or zirconium found in commercial alloys such as T-111 and Cb-752 can lead to aging embrittlement and increased susceptibility to hydrogen embrittlement of ternary and more complex alloys. Modification of alloy composition helps to eliminate the embrittlement problem.

  16. Thermal aging effects in refractory metal alloys

    NASA Technical Reports Server (NTRS)

    Stephens, Joseph R.

    1987-01-01

    The alloys of niobium and tantalum are attractive from a strength and compatibility viewpoint for high operating temperatures required in materials for fuel cladding, liquid metal transfer, and heat pipe applications in space power systems that will supply from 100 kWe to multi-megawatts for advanced space systems. To meet the system requirements, operating temperatures ranging from 1100 to 1600 K have been proposed. Expected lives of these space power systems are from 7 to 10 yr. A program is conducted at NASA Lewis to determine the effects of long-term, high-temperature exposure on the microstructural stability of several commercial tantalum and niobium alloys. Variables studied in the investigation include alloy composition, pre-age annealing temperature, aging time, temperature, and environment (lithium or vacuum), welding, and hydrogen doping. Alloys are investigated by means of cryogenic bend tests and tensile tests. Results show that the combination of tungsten and hafnium or zirconium found in commercial alloys such as T-111 and Cb-752 can lead to aging embrittlement and increased susceptibility to hydrogen embrittlement of ternary and more complex alloys. Modification of alloy composition helps to eliminate the embrittlement problem.

  17. PRODUCTION OF PLUTONIUM METAL

    DOEpatents

    Lyon, W.L.; Moore, R.H.

    1961-01-17

    A process is given for producing plutonium metal by the reduction of plutonium chloride, dissolved in alkali metal chloride plus or minus aluminum chloride, with magnesium or a magnesium-aluminum alloy at between 700 and 800 deg C and separating the plutonium or plutonium-aluminum alloy formed from the salt.

  18. Plutonium Immobilization Task 5.6 Metal Conversion: Milestone Report - Perform Feasibility Demonstrations on Pu-Al Alloys

    SciTech Connect

    Zundelevich, Y; Kerns, J; Bannochie, C

    2001-04-12

    The Plutonium Conversion Task within the Plutonium Immobilization Program (PIP) transforms incoming plutonium (Pu) feed materials into an oxide acceptable for blending with ceramic precursors. One of the feed materials originally planned for PIP was unirradiated fuel, which consisted mainly of the Zero Power Plutonium Reactor (ZPPR) fuel. Approximately 3.5 metric tons of Pu is in ZPPR fuel. The ZPPR fuel is currently stored at the Argonne National Laboratory-West as stainless steel clad metal plates and oxide pellets, with the vast majority of the Pu in the metal plates. The metal plates consist of a Pu-U-Mo alloy (containing 90% of the ZPPR plutonium metal) and a Pu-Al alloy (containing 10% of the ZPPR plutonium metal). The Department of Energy (DOE) decided that ZPPR fuel is a national asset and, therefore, not subject to disposition. This report documents work done prior to that decision. The Hydnde-Oxidation (HYDOX) Process was selected as the method for Metal Conversion in PIP because it provides a universal means for preparing oxide from all feed materials. HYDOX incorporates both the hydride process, originally developed to separate Pu from other pit materials, as well as the oxide formation step. Plutonium hydride is very reactive and is readily converted to either the nitride or the oxide. A previous feasibility study demonstrated that the Pu-U-Mo alloy could be successfully converted to oxide via the HYDOX Process. Another Metal Conversion milestone was to demonstrate the feasibility of the HYDOX Process for converting plutonium-aluminum (Pu-Al) alloy in ZPPR fuel plates to an acceptable oxide. This report documents the results of the latter feasibility study which was performed before the DOE decision to retain ZPPR fuel rather than immobilize it.

  19. Strength and fracture of uranium, plutonium and several their alloys under shock wave loading

    NASA Astrophysics Data System (ADS)

    Golubev, V. K.

    2012-08-01

    Results on studying the spall fracture of uranium, plutonium and several their alloys under shock wave loading are presented in the paper. The problems of influence of initial temperature in a range of - 196 - 800∘C and loading time on the spall strength and failure character of uranium and two its alloys with molybdenum and both molybdenum and zirconium were studied. The results for plutonium and its alloy with gallium were obtained at a normal temperature and in a temperature range of 40-315∘C, respectively. The majority of tests were conducted with the samples in the form of disks 4 mm in thickness. They were loaded by the impact of aluminum plates 4 mm thick through a copper screen 12 mm thick serving as the cover or bottom part of a special container. The character of spall failure of materials and the damage degree of samples were observed on the longitudinal metallographic sections of recovered samples. For a concrete test temperature, the impact velocity was sequentially changed and therefore the loading conditions corresponding to the consecutive transition from microdamage nucleation up to complete macroscopic spall fracture were determined. The conditions of shock wave loading were calculated using an elastic-plastic computer program. The comparison of obtained results with the data of other researchers on the spall fracture of examined materials was conducted.

  20. Spall fracture and strength of uranium, plutonium and their alloys under shock wave loading

    NASA Astrophysics Data System (ADS)

    Golubev, Vladimir

    2015-06-01

    Numerous results on studying the spall fracture phenomenon of uranium, two its alloys with molybdenum and zirconium, plutonium and its alloy with gallium under shock wave loading are presented in the paper. The majority of tests were conducted with the samples in the form of disks 4mm in thickness. They were loaded by the impact of aluminum plates 4mm thick through a copper screen serving as the cover or bottom part of a special container. The initial temperature of samples was changed in the range of -196 - 800 C degree for uranium and 40 - 315 C degree for plutonium. The character of spall failure of materials and the degree of damage for all tested samples were observed on the longitudinal metallographic sections of recovered samples. For a concrete test temperature, the impact velocity was sequentially changed and therefore the loading conditions corresponding to the consecutive transition from microdamage nucleation up to complete macroscopic spall fracture were determined. Numerical calculations of the conditions of shock wave loading and spall fracture of samples were performed in the elastoplastic approach. Several two- and three-dimensional effects of loading were taken into account. Some results obtained under conditions of intensive impulse irradiation and intensive explosive loading are presented too. The rather complete analysis and comparison of obtained results with the data of other researchers on the spall fracture of examined materials were conducted.

  1. Spent fuel temperature and age determination from the analysis of uranium and plutonium isotopics

    SciTech Connect

    Scott, Mark R; Eccleston, George W; Bedell, Jeffrey J; Lockard, Chanelle M

    2009-01-01

    The capability to determine the age (time since irradiation) of spent fuel can be useful for verification and safeguards. While the age of spent fuel can be determined based on measurements of short-lived fission products, these measurements are not routinely done nor generally reported. As an alternative, age can also be determined if the uranium (U) and plutonium (Pu) isotopic values are available. Uranium isotopics are not strongly affected by fuel temperature, and bumup is determined from the {sup 235}U and {sup 236}U isotopic values. Age is calculated after estimating the {sup 241}Pu at the end of irradiation while accounting for the fuel temperature, which is determined from {sup 239}Pu or {sup 240}Pu. Burnup and age determinations are calibrated to reactor models that provide uranium and plutonium isotopics over the range of fuel irradiation. The reactor model must contain sufficient fidelity on details of the reactor type, fuel burnup, irradiation history, initial fuel enrichment and fuel temperature to obtain accurate isotopic calculations. If the latter four are unknown, they can be derived from the uranium and plutonium isotopics. Fuel temperature has a significant affect on the production of plutonium isotopics; therefore, one group cross section reactor models, such as ORIGEN, cannot be used for these calculations. Multi-group cross section set codes, such as Oak Ridge National Laboratory's TRITON code, must be used.

  2. FORM AND AGING OF PLUTONIUM IN SAVANNAH RIVER SITE WASTE TANK 18

    SciTech Connect

    Hobbs, D.

    2012-02-24

    This report provides a summary of the effects of aging on and the expected forms of plutonium in Tank 18 waste residues. The findings are based on available information on the operational history of Tank 18, reported analytical results for samples taken from Tank 18, and the available scientific literature for plutonium under alkaline conditions. These findings should apply in general to residues in other waste tanks. However, the operational history of other waste tanks should be evaluated for specific conditions and unique operations (e.g., acid cleaning with oxalic acid) that could alter the form of plutonium in heel residues. Based on the operational history of other tanks, characterization of samples from the heel residues in those tanks would be appropriate to confirm the form of plutonium. During the operational period and continuing with the residual heel removal periods, Pu(IV) is the dominant oxidation state of the plutonium. Small fractions of Pu(V) and Pu(VI) could be present as the result of the presence of water and the result of reactions with oxygen in air and products from the radiolysis of water. However, the presence of Pu(V) would be transitory as it is not stable at the dilute alkaline conditions that currently exists in Tank 18. Most of the plutonium that enters Savannah River Site (SRS) high-level waste (HLW) tanks is freshly precipitated as amorphous plutonium hydroxide, Pu(OH){sub 4(am)} or hydrous plutonium oxide, PuO{sub 2(am,hyd)} and coprecipitated within a mixture of hydrous metal oxide phases containing metals such as iron, aluminum, manganese and uranium. The coprecipitated plutonium would include Pu{sup 4+} that has been substituted for other metal ions in crystal lattice sites, Pu{sup 4+} occluded within hydrous metal oxide particles and Pu{sup 4+} adsorbed onto the surface of hydrous metal oxide particles. The adsorbed plutonium could include both inner sphere coordination and outer sphere coordination of the plutonium. PuO{sub 2

  3. Fundamental and applied studies of helium ingrowth and aging in plutonium

    SciTech Connect

    Stevens, M.F.; Zocco, T.; Albers, R.; Becker, J.D.; Walter, K.; Cort, B.; Paisley, D.; Nastasi, M.

    1998-12-31

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The purpose of this project was to develop new capabilities to assess the nucleation and growth of helium-associated defects in aged plutonium metal. This effort involved both fundamental and applied models to assist in predicting the transport and kinetics of helium in the metal lattice as well as ab initio calculations of the disposition of gallium in the fcc plutonium lattice and its resulting effects on phase stability. Experimentally this project aimed to establish experimental capabilities crucial to the prediction of helium effects in metals, such as transmission electron microscopy, thermal helium effusion, and the development of a laser-driven mini-flyer for understanding the role of helium and associated defects on shock response of plutonium surrogates.

  4. 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.

  5. Ab initio study of gallium stabilized δ-plutonium alloys and hydrogen-vacancy complexes.

    PubMed

    Hernandez, Sarah C; Schwartz, Daniel S; Taylor, Christopher D; Ray, Asok K

    2014-06-11

    All-electron density functional theory was used to investigate δ-plutonium (δ-Pu) alloyed with gallium (Ga) impurities at 3.125, 6.25, 9.375 atomic (at)% Ga concentrations. The results indicated that the lowest energy structure is anti-ferromagnetic, independent of the Ga concentration. At higher Ga concentrations (>3.125 at%), the position of the Ga atoms are separated by four nearest neighbor Pu-Pu shells. The results also showed that the lattice constant contracts with increasing Ga concentration, which is in agreement with experimental data. Furthermore with increasing Ga concentration, the face-centered-cubic structure becomes more stably coupled with increasing short-range disorder. The formation energies show that the alloying process is exothermic, with an energy range of -0.028 to -0.099 eV/atom. The analyses of the partial density of states indicated that the Pu-Ga interactions are dominated by Pu 6d and Ga 4p hybridizations, as well as Ga 4s-4p hybridizations. Finally, the computed formation energies for vacancy and hydrogen-vacancy complexes within the 3.125 at% Ga cell were 1.12 eV (endothermic) and -3.88 eV (exothermic), respectively. In addition, the hydrogen atom prefers to interact much more strongly to the Pu atom than the Ga atom in the hydrogen-vacancy complex. PMID:24832613

  6. Atomistic model of helium bubbles in gallium-stabilized plutonium alloys

    SciTech Connect

    Valone, S. M.; Baskes, M. I.; Martin, R. L.

    2006-06-01

    The varying thermodynamic stability of gallium- (Ga-) stabilized plutonium (Pu) alloys with temperature affords a unique setting for the development of self-irradiation damage. Here, fundamental characteristics of helium (He) bubbles in these alloys with respect to temperature, gallium concentration, and He-to-vacancy ratio are modeled at the atomistic level with a modified embedded atom potential that takes account of this varying stability. Aside from the bubbles themselves, the surrounding matrix material is single-crystal metal or alloy. As a function of temperature, with a 2:1 He-to-vacancy ratio in a 5-at. % Ga fcc lattice, a 1.25-nm bubble is very stable up to about 1000 K. At 1000 K, the bubble distorts the surrounding lattice and precipitates a liquid zone, as is consistent with the phase diagram for the model material. Between 300 and 500 K, this same bubble relaxes slightly through interstitial emission. At 300 K, with a 2:1 He-to-vacancy ratio in a 2.5-at. % Ga fcc lattice, the Ga stabilization is less effective in the model to the point where the bubble distorts the local lattice and expands significantly. Similarly, at 300 K, if the He-to-vacancy ratio is increased to 3:1, there is significant local lattice distortion, as well as ejection of some He atoms into the lattice. The formation of new bubbles is not observed, because those events take place on a longer time scale than can be simulated with the present approach.

  7. THERMODYNAMICS AND KINETICS OF PHASE TRANSFORMATIONS IN PLUTONIUM ALLOYS - PART I

    SciTech Connect

    Turchi, P A; Kaufman, L; Liu, Z; Zhou, S

    2004-08-18

    In this report we investigate order, stability, and phase transformations for a series of actinide-based alloys. The statics and kinetics of precipitation and ordering in this class of alloys are modeled with a scheme that couples fundamental information on the alloy energetics obtained from experimental and assessed thermo-chemical data to the CALPHAD approach commonly used in industry for designing alloys with engineering specificity with the help of the Thermo-Calc software application. The CALPHAD approach is applied to the study of the equilibrium thermodynamic properties of Pu-based alloys, Pu-X, where X=Al, Fe, Ga. The assessment of the equilibrium phase diagrams in the whole range of alloy composition has been performed with the PARROT module of the Thermo-Calc application software. Predictions are made on the low temperature and Pu-rich side of the phase diagrams of Pu-Ga and Pu-Al for which controversy has been noted in the past. The validity of the assessed thermo-chemical database will be discussed by comparing predicted heats of transformation for pure Pu with measured values from differential scanning calorimetry analysis. An overall picture for the stability properties of Pu-Ga and Pu-Al that reconciles the results of past studies carried out on these alloys is proposed. Results on phase stability in the ternary Fe-Ga-Pu and Al-Fe-Pu alloys are discussed. The information collected in this study is then used to model metastability, long-term stability and aging for this class of alloys by coupling Thermo-Calc with DICTRA, a series of modules that allow the analysis of DIffusion Controlled TRAnsformations. Kinetics information is then summarized in so-called TTT (temperature-time-transformations) diagrams for the most relevant phases of actinide alloys. Specifically, results are presented on kinetics of phase transformations associated with the eutectoid-phase decomposition reaction occurring at low temperature, and with the martensitic transformation

  8. Temperature and concentration dependences of the electrical resistivity for alloys of plutonium with americium under normal conditions

    SciTech Connect

    Tsiovkin, Yu. Yu. Povzner, A. A.; Tsiovkina, L. Yu.; Dremov, V. V.; Kabirova, L. R.; Dyachenko, A. A.; Bystrushkin, V. B.; Ryabukhina, M. V.; Lukoyanov, A. V.; Shorikov, A. O.

    2010-01-15

    The temperature and concentration dependences of the electrical resistivity for alloys of americium with plutonium are analyzed in terms of the multiband conductivity model for binary disordered substitution-type alloys. For the case of high temperatures (T > {Theta}{sub D}, {Theta}{sub D} is the Debye temperature), a system of self-consistent equations of the coherent potential approximation has been derived for the scattering of conduction electrons by impurities and phonons without any constraints on the interaction intensity. The definitions of the shift and broadening operator for a single-electron level are used to show qualitatively and quantitatively that the pattern of the temperature dependence of the electrical resistivity for alloys is determined by the balance between the coherent and incoherent contributions to the electron-phonon scattering and that the interference conduction electron scattering mechanism can be the main cause of the negative temperature coefficient of resistivity observed in some alloys involving actinides. It is shown that the great values of the observed resistivity may be attributable to interband transitions of charge carriers and renormalization of their effective mass through strong s-d band hybridization. The concentration and temperature dependences of the resistivity for alloys of plutonium and americium calculated in terms of the derived conductivity model are compared with the available experimental data.

  9. Performance testing of aged hydrogen getters against criteria for interim safe storage of plutonium bearing materials.

    SciTech Connect

    Shepodd, Timothy J.; Nissen, April; Buffleben, George M.

    2006-01-01

    Hydrogen getters were tested for use in storage of plutonium-bearing materials in accordance with DOE's Criteria for Interim Safe Storage of Plutonium Bearing Materials. The hydrogen getter HITOP was aged for 3 months at 70 C and tested under both recombination and hydrogenation conditions at 20 and 70 C; partially saturated and irradiated aged getter samples were also tested. The recombination reaction was found to be very fast and well above the required rate of 45 std. cc H2h. The gettering reaction, which is planned as the backup reaction in this deployment, is slower and may not meet the requirements alone. Pressure drop measurements and {sup 1}H NMR analyses support these conclusions. Although the experimental conditions do not exactly replicate the deployment conditions, the results of our conservative experiments are clear: the aged getter shows sufficient reactivity to maintain hydrogen concentrations below the flammability limit, between the minimum and maximum deployment temperatures, for three months. The flammability risk is further reduced by the removal of oxygen through the recombination reaction. Neither radiation exposure nor thermal aging sufficiently degrades the getter to be a concern. Future testing to evaluate performance for longer aging periods is in progress.

  10. Microstructure evolution of 7050 Al alloy during age-forming

    SciTech Connect

    Chen, Junfeng; Zou, Linchi; Li, Qiang; Chen, Yulong

    2015-04-15

    The microstructure evolution of the 7050 Al alloy treated by age-forming was studied using a designed device which can simulate the age-forming process. The grain shape, grain boundary misorientation and grain orientation evolution of 7050 Al alloy during age-forming have been quantitatively characterized by electron backscattering diffraction technique. The results show that age-forming produced abundant low-angle boundaries and elongated grains, which attributed to stress induced dislocation movement and grain boundary migration during the age-forming process. On the other side, the stress along rolling direction caused some unstable orientation grains to rotate towards the Brass and S orientations during the age-forming process. Hence, the intensity of the rolling texture orientation in age-formed samples is enhanced. But this effect decays gradually with increasing aging time, since stress decreases and precipitation hardening occurs during the age-forming process. - Highlights: • Quantitative analysis of grain evolution of 7050 Al alloys during age-forming • Stress induces some grain rotation of 7050 Al alloys during age-forming. • Creep leads to elongate grain of 7050 Al alloys during age-forming. • Obtains a trend on texture evolution during age-forming applied stress.

  11. Development Program for Natural Aging Aluminum Casting Alloys

    SciTech Connect

    Dr. Geoffrey K. Sigworth

    2004-05-14

    A number of 7xx aluminum casting alloys are based on the ternary Al-Zn-Mg system. These alloys age naturally to high strength at room temperature. A high temperature solution and aging treatment is not required. Consequently, these alloys have the potential to deliver properties nearly equivalent to conventional A356-T6 (Al-Si-Mg) castings, with a significant cost saving. An energy savings is also possible. In spite of these advantages, the 7xx casting alloys are seldom used, primarily because of their reputation for poor castibility. This paper describes the results obtained in a DOE-funded research study of these alloys, which is part of the DOE-OIT ''Cast Metals Industries of the Future'' Program. Suggestions for possible commercial use are also given.

  12. Evolving Density and Static Mechanical Properties in Plutonium from Self-Irradiation

    SciTech Connect

    Chung, B W; Thompson, S R; Lema, K E; Hiromoto, D S; Ebbinghaus, B B

    2008-07-31

    Plutonium, because of its self-irradiation by alpha decay, ages by means of lattice damage and helium in-growth. These integrated aging effects result in microstructural and physical property changes. Because these effects would normally require decades to measure, studies are underway to assess the effects of extended aging on the physical properties of plutonium alloys by incorporating roughly 7.5 weight % of highly specific activity isotope {sup 238}Pu into the {sup 239}Pu metal to accelerate the aging process. This paper presents updated results of self-irradiation effects on {sup 238}Pu-enriched alloys measured by immersion density, dilatometry, and tensile tests. After nearly 90 equivalent years of aging, both the immersion density and dilatometry show that the enriched alloys continue to decreased in density by {approx}0.002% per year, without void swelling. Quasi-static tensile measurements show that the aging process increases the strength of plutonium alloys.

  13. Strain aging in tungsten heavy alloys

    SciTech Connect

    Dowding, R.J.; Tauer, K.J. . Materials Technology Lab.)

    1991-01-01

    This paper reports on tungsten heavy alloys which are two-phase mixtures of body center cubic (BCC) tungsten surrounded by a face center cubic (FCC) matrix. The matrix is most often composed of nickel and iron in a ratio of 70:30 but, occasionally, the matrix may also contain cobalt or copper. Nickel, however, is always the primary matrix component. The tungsten heavy alloy is fabricated through powder metallurgy techniques. Elemental powders are blended, pressed to shape, and sintered. Depending upon the tungsten content, the sintering temperatures are usually in the range of 1450{degrees}C to 1525{degrees}C. These temperatures are high enough that, as a result, the matrix is at the liquid phase and the process is known as liquid phase sintering. At the liquid phase temperature, the matrix becomes saturated with tungsten, but this does not change the FCC character of the matrix. The sintering is usually done in a hydrogen atmosphere furnace in order to reduce the oxides on the tungsten powder surfaces and create clean, active surfaces which will enhance the adherence between the tungsten and the matrix. The hydrogen atmosphere also creates the presence of excess dissolved hydrogen in the alloy. It has been shown that the hydrogen degrades the toughness and ductility of the heavy alloy. A post-sintering vacuum heat treatment is generally required to insure that there is no residual hydrogen present. The as-sintered tensile strength of a 90% tungsten, 7% nickel, 3% iron alloy (90W) is in the range of 800 to 940 MPa and can be increased significantly by cold working, usually rolling or swaging. Swaging to reductions in area of 20% can result in tensile strengths of 1250 MPa or more. As the strength increases, the elongation, which may have been 30% or more, decreases to less than 5%.

  14. Mechanical Properties and Corrosion Characteristics of Thermally Aged Alloy 22

    SciTech Connect

    Rebak, R B; Crook, P

    2002-05-30

    Alloy 22 (UNS N06022) is a candidate material for the external wall of the high level nuclear waste containers for the potential repository site at Yucca Mountain. In the mill-annealed (MA) condition, Alloy 22 is a single face centered cubic phase. When exposed to temperatures on the order of 600 C and above for times higher than 1 h, this alloy may develop secondary phases that reduce its mechanical toughness and corrosion resistance. The objective of this work was to age Alloy 22 at temperatures between 482 C and 760 C for times between 0.25 h and 6,000 h and to study the mechanical and corrosion performance of the resulting material. Aging was carried out using wrought specimens as well as gas tungsten arc welded (GTAW) specimens. Mechanical and corrosion testing was carried out using ASTM standards. Results show-that the higher the aging temperature and the longer the aging time, the lower the impact toughness of the aged material and the lower its corrosion resistance. However, extrapolating both mechanical and corrosion laboratory data predicts that Alloy 22 will remain corrosion resistant and mechanically robust for the projected lifetime of the waste container.

  15. Initial aging phenomena in copper-chromium alloys

    NASA Technical Reports Server (NTRS)

    Suzuki, H.; Motohiro, K.

    1985-01-01

    The effects of quenching and aging temperatures on the initial aging curves of Cu-Cr alloy were examined mainly by means of electrical resistivity measurements. Three Cu-Cr alloy specimens having 0.24, 0.74, and 1.0% Cr were solution-treated at 950-1050 C, quenched into ice-water, and subsequently aged at 300-500 C. The results were as follows: (1) At the very early stage of aging (within about 30 sec), an abrupt decrease of resistivity with lowering aging tempratures. (T sub A) and rising solution temperatures (T sub S) was observed at (T sub A) up to about 400 C. In contrast, a transient increase of resistivity with rising T sub A and lowering T sub S was observed at T sub A from about 450 to 500 C. These phenomena seem to be caused by a rapid formation of solute clusters and the reversion of clusters formed during quenching, which are enhanced by quenched-in vacancies, respectively. (2) The amount of precipitation increased at the latter stage of aging with rising T sub S and T sub A as generally expected, where T sub S was not so high as to form secondary defects. (3) As a result, the initial aging phenomena in Cr-Cr alloy were revealed to be complicated against expectations. This was considered to be due to the migration energy of vacancies so larger in Cu-base.

  16. The iodine-plutonium-xenon age of the Moon-Earth system revisited.

    PubMed

    Avice, G; Marty, B

    2014-09-13

    Iodine-plutonium-xenon isotope systematics have been used to re-evaluate time constraints on the early evolution of the Earth-atmosphere system and, by inference, on the Moon-forming event. Two extinct radionuclides ((129)I, T1/2=15.6 Ma and (244)Pu, T1/2=80 Ma) have produced radiogenic (129)Xe and fissiogenic (131-136)Xe, respectively, within the Earth, the related isotope fingerprints of which are seen in the compositions of mantle and atmospheric Xe. Recent studies of Archaean rocks suggest that xenon atoms have been lost from the Earth's atmosphere and isotopically fractionated during long periods of geological time, until at least the end of the Archaean eon. Here, we build a model that takes into account these results. Correction for Xe loss permits the computation of new closure ages for the Earth's atmosphere that are in agreement with those computed for mantle Xe. The corrected Xe formation interval for the Earth-atmosphere system is [Formula: see text] Ma after the beginning of Solar System formation. This time interval may represent a lower limit for the age of the Moon-forming impact. PMID:25114317

  17. Aging of Alloy 617 at 650 and 750 Degrees C

    SciTech Connect

    Julian Benz; Thomas Lillo; Richard Wright

    2013-01-01

    Alloy 617 has been selected as the primary candidate for heat exchanger applications in advanced reactors. For the VHTR this application could require extended service up to a reactor outlet temperature of 950°C. A key hurdle to using this alloy in the VHTR heat exchanger application is qualifying the alloy for Section III of the ASME Boiler and Pressure Vessel Code. In order to Code qualify the material it is necessary to characterize the influence of long term aging on the mechanical behavior. Alloy 617 has been aged at 650 and 750°C for times up to 5300 hours. The microstructure after aging has been characterized using optical and transmission electron microscopies. It has been determined that in addition to carbides, a significant volume fraction of ?’ phase (Ni3Al) is formed at these temperatures. The ?’ does not contribute significantly to changing the tensile or impact properties of the aged material. It does, however, appear to increase creep resistance and impede creep crack growth.

  18. Morphological development during ageing of Ni-W alloys

    SciTech Connect

    Zhao, H.; Aust, K.T.; Weatherly, G.C. )

    1992-01-01

    This paper discusses the ageing response of a Ni-W alloy studies by electron microscopy. Two particles morphologies develop on ageing: A semi-coherent lath shaped particle and a coherent multi-variant domain (MVD) plate-shape particle composed of two perpendicular twin variants. The factors responsible for the evolution of these shapes on coarsening are discussed. A comparison of the energies associated with the two morphologies suggests that the MVD particles will be more stable.

  19. Corrosion performance of a nickel-molybdenum-chromium alloy: Effects of aging, alloying elements, and electrolyte composition

    SciTech Connect

    Rebak, R.B.; Srivastava, S.K.

    1999-04-01

    General and stress corrosion cracking (SCC) behaviors of a Ni-Mo-Cr alloy were assessed in the mill-annealed and aged conditions. Performance of this Ni-25% Mo-8% Cr alloy (alloy 242 [proposed UNS N10242]) was compared to the performance of a Ni-Mo alloy (alloy B-3 [UNS N10675]) and a Ni-Cr-Mo alloy (C-2000 [UNS N06200]). Results showed the general corrosion rate of alloy 242 in reducing acids was slightly higher than that of alloy B-3. However, in mildly oxidizing conditions, the corrosion rate of alloy 242 was lower than that of alloy B-3. Effects of electrolyte and alloy composition on the general corrosion rate were studied. After aging at 650 C (1,200 F) for 24 h, the corrosion rate of alloy 242 increased slightly, particularly in strongly reducing conditions. Alloy 242 was resistant to SCC but was prone to hydrogen-induced cracking, especially in the aged condition.

  20. Plutonium and the Rio Grande: Environmental change and contamination in the nuclear age

    SciTech Connect

    Graf, W.L.

    1994-12-31

    An attempt is made to analyze questions concerning the issue of plutonium in the Rio Grande. The author describes in great detail how he arrived at the conclusions. The objective has been to produce research that is absolutely transparent, so that its results can be fairly evaluated and duplicated by anyone. The results of this work show that plutonium from Los Alamos National Laboratory and atmospheric fallout has been deposited along the Rio Grande in small, though detectable, quantities in certain predictable places.

  1. Analysis of the Effect of Time, Temperature, and Fuel Age on Helium Release from 238-Plutonium Dioxide Fuel

    NASA Astrophysics Data System (ADS)

    Barklay, Chadwick D.; Kramer, Daniel P.; Ruhkamp, Joseph D.

    2005-02-01

    The compound 238-plutonium dioxide has been employed over the last several decades as the fuel of choice in fabricating nuclear powered thermal to electrical converters. The alpha decay of 238-plutonium results in the generation of helium ions as a function of time. While the quantity of helium formed within the fuel can be easily calculated, its diffusion and/or release mechanism as a function of time, temperature, fuel quantity and age needs to be characterized. Within the scope of this paper the principle interest centers on determining the expected quantity of helium that will be released from solid 238-plutonium dioxide fuel forms enclosed within a primary containment vessel (PCV) under Hypothetical Accident Conditions (HAC) as described in 10 CFR 71.73(4). Once the quantity of helium released during HAC has been determined, the partial pressure increase due to the helium release can be calculated for a given shipping configuration. This partial pressure increase due to helium release during HAC for a selected shipping configuration can then be used to determine if the structural integrity of the package will be maintained or compromised during HAC. However, it is important to recognize that helium release is not a function of a particular shipping package, but as shall be demonstrated is a function of time, temperature, and fuel quantity and age.

  2. Analysis of the Effect of Time, Temperature, and Fuel Age on Helium Release from 238-Plutonium Dioxide Fuel

    SciTech Connect

    Barklay, Chadwick D.; Kramer, Daniel P.; Ruhkamp, Joseph D.

    2005-02-06

    The compound 238-plutonium dioxide has been employed over the last several decades as the fuel of choice in fabricating nuclear powered thermal to electrical converters. The alpha decay of 238-plutonium results in the generation of helium ions as a function of time. While the quantity of helium formed within the fuel can be easily calculated, its diffusion and/or release mechanism as a function of time, temperature, fuel quantity and age needs to be characterized. Within the scope of this paper the principle interest centers on determining the expected quantity of helium that will be released from solid 238-plutonium dioxide fuel forms enclosed within a primary containment vessel (PCV) under Hypothetical Accident Conditions (HAC) as described in 10 CFR 71.73(4). Once the quantity of helium released during HAC has been determined, the partial pressure increase due to the helium release can be calculated for a given shipping configuration. This partial pressure increase due to helium release during HAC for a selected shipping configuration can then be used to determine if the structural integrity of the package will be maintained or compromised during HAC. However, it is important to recognize that helium release is not a function of a particular shipping package, but as shall be demonstrated is a function of time, temperature, and fuel quantity and age.

  3. Oxide Film Aging on Alloy 22 in Halide Containing Solutions

    SciTech Connect

    Rodriguez, Martin A.; Carranza, Ricardo M.; Rebak, Raul B.

    2007-07-01

    Passive and corrosion behaviors of Alloy 22 in chloride and fluoride containing solutions, changing the heat treatment of the alloy, the halide concentration and the pH of the solutions at 90 deg. C, was investigated. The study was implemented using electrochemical techniques, which included open circuit potential monitoring over time, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements carried out at open circuit and at passivity potentials. Corrosion rates obtained by EIS measurements after 24 h immersion in naturally aerated solutions were below 0.5 {mu}m/year. The corrosion rates were practically independent of solution pH, alloy heat treatment and halide ion nature and concentration. EIS low frequency resistance values increased with applied potential in the passive domain and with polarization time in pH 6 - 1 M NaCl at 90 deg. C. This effect was attributed to an increase in the oxide film thickness and oxide film aging. High frequency capacitance measurements indicated that passive oxide on Alloy 22 presented a double n-type/p-type semiconductor behavior in the passive potential range. (authors)

  4. ISOTHERMAL (DELTA)/(ALPHA-PRIME) TRANSFORMATION AND TTT DIAGRAM IN A PLUTONIUM GALLIUM ALLOY

    SciTech Connect

    Oudot, B P; Blobaum, K M; Wall, M A; Schwartz, A J

    2005-11-11

    Differential scanning calorimetry (DSC) is used as an alternative approach to determining the tine-temperature-transformation (TTT) diagram for the martensitic delta to alpha-prime transformation in a Pu-2.0 at% Ga alloy. Previous work suggests that the TTT diagram for a similar alloy exhibits an unusual double-C curve for isothermal holds of less than 100 minutes. Here, we extend this diagram to 18 hours, and confirm the double-C curve behavior. When the sample is cooled prior to the isothermal holds, the delta to alpha-prime transformation is observed as several overlapping exothermic peaks. These peaks are very reproducible, and they are believed to be the result of different kinds of delta to alpha-prime martensitic transformation. This may be due to the presence of different nucleation sites and/or different morphologies.

  5. Forming an age hardenable aluminum alloy with intermediate annealing

    NASA Astrophysics Data System (ADS)

    Wang, Kaifeng; Carsley, John E.; Stoughton, Thomas B.; Li, Jingjing; Zhang, Lianhong; He, Baiyan

    2013-12-01

    A method to improve formability of aluminum sheet alloys by a two-stage stamping process with intermediate annealing was developed for a non-age hardenable Al-Mg alloy where the annealing heat treatment provided recovery of cold work from the initial stamping and recrystallization of the microstructure to enhance the forming limits of the material. This method was extended to an age hardenable, Al-Mg-Si alloy, which is complicated by the competing metallurgical effects during heat treatment including recovery (softening effect) vs. precipitation (hardening effect). An annealing heat treatment process condition was discovered wherein the stored strain energy from an initial plastic deformation can be sufficiently recovered to enhance formability in a second deformation; however, there is a deleterious effect on subsequent precipitation hardening. The improvement in formability was quantified with uniaxial tensile tests as well as with the forming limit diagram. Since strain-based forming limit curves (FLC) are sensitive to pre-strain history, both stress-based FLCs and polar-effective-plastic-strain (PEPS) FLCs, which are path-independent, were used to evaluate the forming limits after preform annealing. A technique was developed to calculate the stress-based FLC in which a residual-effective-plastic-strain (REPS) was determined by overlapping the hardening curve of the pre-strained and annealed material with that of the simply-annealed- material. After converting the strain-based FLCs using the constant REPS method, it was found that the stress-based FLCs and the PEPS FLCs of the post-annealed materials were quite similar and both tools are applicable for evaluating the forming limits of Al-Mg-Si alloys for a two-step stamping process with intermediate annealing.

  6. The solubility of hydrogen and deuterium in alloyed, unalloyed and impure plutonium metal

    SciTech Connect

    Richmond, Scott; Bridgewater, Jon S; Ward, John W; Allen, Thomas H

    2010-01-01

    Hydrogen is exothermically absorbed in many transition metals, all rare earths and the actinides. The hydrogen gas adsorbs, dissociates and diffuses into these metals as atomic hydrogen. Absorbed hydrogen is generally detrimental to Pu, altering its properties and greatly enhancing corrosion. Measuring the heat of solution of hydrogen in Pu and its alloys provides significant insight into the thermodynamics driving these changes. Hydrogen is present in all Pu metal unless great care is taken to avoid it. Heats of solution and formation are provided along with evidence for spinodal decomposition.

  7. Aging Behavior of Al 6061 Alloy Processed by High-Pressure Torsion and Subsequent Aging

    NASA Astrophysics Data System (ADS)

    Mohamed, Intan Fadhlina; Lee, Seungwon; Edalati, Kaveh; Horita, Zenji; Hirosawa, Shoichi; Matsuda, Kenji; Terada, Daisuke

    2015-06-01

    A process to achieve strengthening in an Al 6061 alloy by grain refinement to ~200 nm using high-pressure torsion (HPT) and fine precipitation using aging treatment is studied. It is shown that although aging of the HPT-processed sample is effective for extra strengthening of the alloy, the imposed shear strain and the aging temperature should be selected carefully. The HPT processing after 5 turns leads high saturation hardness and tensile strength of 163 Hv and 470 MPa, respectively. The hardness at the saturation level remains the same during aging at 373 K (100 °C), while the hardness decreases by aging at 423 K (150 °C). When the disks are processed for 0.75 turns (lower shear strains) and aged at 373 K (100 °C), the hardness increases above the hardness level at the saturation because of the formation of B' and β' precipitates. Quantitative analyses indicate that three major hardening mechanisms contribute to the total hardening: grain boundary hardening through the Hall-Petch relationship, dislocation hardening through the Bailey-Hirsch relationship and precipitation hardening through the Orowan relationship. This study shows that the contribution of different strengthening mechanisms can be estimated using a linear additive relationship in ultrafine-grained aluminum alloys.

  8. Behavior of Fe-ODS Alloys After Thermal Aging Treatments

    NASA Astrophysics Data System (ADS)

    Serrano Garcia, Marta; Hernández-Mayoral, Mercedes; Esparraguera, Elvira Oñorbe

    2016-03-01

    Oxide dispersion alloys are one of the candidates as cladding materials for Gen IV fast reactors, due to their high strength at high temperature, good creep properties, and swelling resistance. This good performance is mainly due to a fine dispersion of nano-oxide particles on the microstructure and to non-grained structure. The microstructural stability and the mechanical properties of a Fe-ODS alloy are studied after different thermal aging experiments at 973 K (700 °C), 5000 hours; 973 K (700 °C), 10,000 hours; and 1123 K (850 °C), 10,000 hours. SEM/EBSD and TEM together with tensile and impact tests on the as-received and thermally aged material have been carried out. In general, for all the tested conditions, a slight softening effect is observed attributed to the changes in the grain structure as well as to the changes in the amount and size of nano-oxide particles. In addition, the aged material shows a lower impact USE value while the DBTT is maintained.

  9. Behavior of Fe-ODS Alloys After Thermal Aging Treatments

    NASA Astrophysics Data System (ADS)

    Serrano Garcia, Marta; Hernández-Mayoral, Mercedes; Esparraguera, Elvira Oñorbe

    2016-06-01

    Oxide dispersion alloys are one of the candidates as cladding materials for Gen IV fast reactors, due to their high strength at high temperature, good creep properties, and swelling resistance. This good performance is mainly due to a fine dispersion of nano-oxide particles on the microstructure and to non-grained structure. The microstructural stability and the mechanical properties of a Fe-ODS alloy are studied after different thermal aging experiments at 973 K (700 °C), 5000 hours; 973 K (700 °C), 10,000 hours; and 1123 K (850 °C), 10,000 hours. SEM/EBSD and TEM together with tensile and impact tests on the as-received and thermally aged material have been carried out. In general, for all the tested conditions, a slight softening effect is observed attributed to the changes in the grain structure as well as to the changes in the amount and size of nano-oxide particles. In addition, the aged material shows a lower impact USE value while the DBTT is maintained.

  10. Phase Transformation Hysteresis in a Plutonium Alloy System: Modeling the Resistivity during the Transformation

    SciTech Connect

    Haslam, J J; Wall, M A; Johnson, D L; Mayhall, D J; Schwartz, A J

    2001-11-14

    We have induced, measured, and modeled the {delta}-{alpha}' martensitic transformation in a Pu-Ga alloy by a resistivity technique on a 2.8-mm diameter disk sample. Our measurements of the resistance by a 4-probe technique were consistent with the expected resistance obtained from a finite element analysis of the 4-point measurement of resistivity in our round disk configuration. Analysis by finite element methods of the postulated configuration of {alpha}' particles within model {delta} grains suggests that a considerable anisotropy in the resistivity may be obtained depending on the arrangement of the {alpha}' lens shaped particles within the grains. The resistivity of these grains departs from the series resistance model and can lead to significant errors in the predicted amount of the {alpha}' phase present in the microstructure. An underestimation of the amount of {alpha}' in the sample by 15%, or more, appears to be possible.

  11. Precipitation Hardening and Statistical Modeling of the Aging Parameters and Alloy Compositions in Al-Cu-Mg-Ag Alloys

    NASA Astrophysics Data System (ADS)

    Al-Obaisi, A. M.; El-Danaf, E. A.; Ragab, A. E.; Soliman, M. S.

    2016-04-01

    The addition of Ag to Al-Cu-Mg systems has been proposed to replace the existing high-strength 2xxx and 7xxx Al alloys. The aged Al-Cu-Mg-Ag alloys exhibited promising properties, due to special type of precipitates named Ω, which cooperate with other precipitates to enhance the mechanical properties significantly. In the present investigation, the effect of changing percentages of alloying elements, aging time, and aging temperature on the hardness values was studied based on a factorial design. According to this design of experiments (DOE)—23 factorial design, eight alloys were cast and hot rolled, where (Cu, Mg, and Ag) were added to aluminum with two different levels for each alloying element. These alloys were aged at different temperatures (160, 190, and 220 °C) over a wide range of time intervals from 10 min. to 64 h. The resulting hardness data were used as an input for Minitab software to model and relate the process variables with hardness through a regression analysis. Modifying the alloying elements' weight percentages to the high level enhanced the hardness of the alloy with about 40% as compared to the alloy containing the low level of all alloying elements. Through analysis of variance (ANOVA), it was figured out that altering the fraction of Cu had the greatest effect on the hardness values with a contribution of about 49%. Also, second-level interaction terms had about 21% of impact on the hardness values. Aging time, quadratic terms, and third-level interaction terms had almost the same level of influence on hardness values (about 10% contribution). Furthermore, the results have shown that small addition of Mg and Ag was enough to improve the mechanical properties of the alloy significantly. The statistical model formulated interpreted about 80% of the variation in hardness values.

  12. Precipitation Hardening and Statistical Modeling of the Aging Parameters and Alloy Compositions in Al-Cu-Mg-Ag Alloys

    NASA Astrophysics Data System (ADS)

    Al-Obaisi, A. M.; El-Danaf, E. A.; Ragab, A. E.; Soliman, M. S.

    2016-06-01

    The addition of Ag to Al-Cu-Mg systems has been proposed to replace the existing high-strength 2xxx and 7xxx Al alloys. The aged Al-Cu-Mg-Ag alloys exhibited promising properties, due to special type of precipitates named Ω, which cooperate with other precipitates to enhance the mechanical properties significantly. In the present investigation, the effect of changing percentages of alloying elements, aging time, and aging temperature on the hardness values was studied based on a factorial design. According to this design of experiments (DOE)—23 factorial design, eight alloys were cast and hot rolled, where (Cu, Mg, and Ag) were added to aluminum with two different levels for each alloying element. These alloys were aged at different temperatures (160, 190, and 220 °C) over a wide range of time intervals from 10 min. to 64 h. The resulting hardness data were used as an input for Minitab software to model and relate the process variables with hardness through a regression analysis. Modifying the alloying elements' weight percentages to the high level enhanced the hardness of the alloy with about 40% as compared to the alloy containing the low level of all alloying elements. Through analysis of variance (ANOVA), it was figured out that altering the fraction of Cu had the greatest effect on the hardness values with a contribution of about 49%. Also, second-level interaction terms had about 21% of impact on the hardness values. Aging time, quadratic terms, and third-level interaction terms had almost the same level of influence on hardness values (about 10% contribution). Furthermore, the results have shown that small addition of Mg and Ag was enough to improve the mechanical properties of the alloy significantly. The statistical model formulated interpreted about 80% of the variation in hardness values.

  13. Plutonium microstructures, part 1

    NASA Astrophysics Data System (ADS)

    Cramer, E. M.; Bergin, J. B.

    1981-09-01

    Illustrations of inclusions that are seen in plutonium metal as a consequence of inherent and tramp impurities, alloy additions, and thermal or mechanical treatments are presented. This part includes illustrations of nonmetallic and intermetallic inclusions characteristic of major impurity elements as an aid to identifying unknowns are included. Historical aspects of the increased purity of laboratory plutonium samples are described and the composition of the etchant solutions are given. The etching procedure used in the preparation of each illustrated sample is described.

  14. Modeling dynamic strain aging of aluminum-magnesium alloys

    NASA Astrophysics Data System (ADS)

    Zhang, Dawei

    This thesis presents atomistic studies and continuum modeling of solute clustering and solute diffusion in Al-Mg alloys, which are considered elements of the mechanism of dynamic strain aging (DSA). Solute clustering in Al-Mg binary alloys is first studied by means of Monte-Carlo simulations. In the undistorted lattice, Mg has a tendency to form a coherent phase. The binding energy of this structure is rather low and it dissolves at room temperature when only dynamic associations of doublets or triples of solute atoms are observed. In presence of dislocations and at room temperature, Mg clusters at cores forming the coherent phase observed in the undistorted lattice at lower temperatures. The size, shape and structure of the cluster cannot be predicted by elementary calculations based on the pressure field generated by the unclustered dislocation. Then diffusion for Mg in Al-Mg alloys is investigated by Molecular Statics and the Nudged Elastic Band method. The activation energy for diffusion of Mg in the bulk is evaluated in the dilute solution limit for the nearest neighbor and the ring mechanisms. It is concluded that bulk diffusion at low and moderate temperatures must be assisted by vacancies. Further, diffusion of Mg along the core of edge, 60° and screw dislocations is studied. The vacancy formation energy in the core and the migration energy for vacancy-assisted Mg is evaluated for a large number of diffusion paths in the core region. The analysis shows that pipe diffusion; which is currently considered as the leading mechanism responsible for dynamic strain aging in these alloys, is too slow in absence of excess vacancies. Finally, the time-dependent Mg solute clustering process is studied using a continuum model calibrated based on atomistic information. The solute atmosphere around an edge dislocation is evaluated in terms of a chemical potential gradient, which is obtained from Monte-Carlo simulations. The solute clustering process is modeled by coupled

  15. 'Age-hardened alloy' based on bulk polycrystalline oxide ceramic

    NASA Astrophysics Data System (ADS)

    Gurnani, Luv; Singh, Mahesh Kumar; Bhargava, Parag; Mukhopadhyay, Amartya

    2015-05-01

    We report here for the first time the development of 'age-hardened/toughened' ceramic alloy based on MgO in the bulk polycrystalline form. This route allows for the facile development of a 'near-ideal' microstructure characterized by the presence of nanosized and uniformly dispersed second-phase particles (MgFe2O4) within the matrix grains, as well as along the matrix grain boundaries, in a controlled manner. Furthermore, the intragranular second-phase particles are rendered coherent with the matrix (MgO). Development of such microstructural features for two-phase bulk polycrystalline ceramics is extremely challenging following the powder metallurgical route usually adopted for the development of bulk ceramic nanocomposites. Furthermore, unlike for the case of ceramic nanocomposites, the route adopted here does not necessitate the usage of nano-powder, pressure/electric field-assisted sintering techniques and inert/reducing atmosphere. The as-developed bulk polycrystalline MgO-MgFe2O4 alloys possess considerably improved hardness (by ~52%) and indentation toughness (by ~35%), as compared to phase pure MgO.

  16. Aging Optimization of Aluminum-Lithium Alloy C458 for Application to Cryotank Structures

    NASA Technical Reports Server (NTRS)

    Sova, B. J.; Sankaran, K. K.; Babel, H. W.; Farahmand, B.; Rioja, R.

    2003-01-01

    This viewgraph report presents an examination of the fracture toughness of aluminum-lithium alloy C458 for use in cryotank structures. Topics cover include: cryogenics, alloy composition, strengthing precipitates in C458, cryogenic fracture toughness improvements, design of experiments for measuring aging optimization of C458 plate and effects of aging of properties of C458 plate.

  17. The microstructure and hydriding characteristics of high temperature aged U-13 at.%Nb alloy

    NASA Astrophysics Data System (ADS)

    Ji, Hefei; Shi, Peng; Li, Ruiwen; Jiang, Chunli; Yang, Jiangrong; Hu, Guichao

    2015-09-01

    Niobium as alloying element significantly improves physical and chemical properties of metallic uranium, exhibiting great application potential in uranium alloy materials. The corrosion resistance performance as well as the internal alloy phase structure of uranium-niobium alloy is closely related to aging processes. Microstructure and hydriding characteristics of the 400 °C/9 h + 500 °C/2 h aged uranium-13 at.% niobium alloys (U-13 at.%Nb) were investigated from the point of view of relationship between the microstructure and growth of the hydriding areas. The microstructure, morphology and composition of the alloy phases before and after the hydriding were well characterized by the laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Experimental results indicated that the hydrogen preferentially reacted with the Nb-depleted phase α-like-U to form monolithic β-UH3Nbx, and the alloy microstructure played an important role in hydride growth.

  18. Effect of delayed aging on mechanical properties of an Al-Cu-Mg alloy

    SciTech Connect

    Ravindranathan, S.P.; Kashyap, K.T.; Kumar, S.R.; Ramachandra, C.; Chatterji, B.

    2000-02-01

    The effect of delayed aging on mechanical properties is characteristically found in Al-Mg-Si alloys. Delayed aging refers to the time elapsed between solutionizing and artificial aging. Delayed aging leads to inferior properties. This effect was investigated in an Al-Cu-Mg alloy (AU2GN) of nominal composition Al-2Cu-1.5Mg-1Fe-1Ni as a function of delay. This alloy also showed a drop in mechanical properties with delay. The results are explained on the basis of Pashley's kinetic model to qualitatively explain the evolution of a coarse precipitate structure with delay. It is found that all the results of delayed aging in the Al-Cu-Mg alloys are similar to those found in Al-Mg-Si alloys.

  19. Effect of scandium on the microstructure and ageing behaviour of cast Al-6Mg alloy

    SciTech Connect

    Kaiser, M.S.; Datta, S.; Roychowdhury, A. Banerjee, M.K.

    2008-11-15

    Microstructural modification and grain refinement due to addition of scandium in Al-6Mg alloy has been studied. Transmission electron microscopy is used to understand the microstructure and precipitation behaviour in Al-6Mg alloy doped with scandium. It is seen from the microstructure that the dendrites of the cast Al-6Mg alloy have been refined significantly due to addition of scandium. Increasing amount of scandium leads to a greater dendrite refinement. The age hardening effect in scandium added Al-6Mg alloys has been studied by subjecting the alloys containing varying amount of scandium ranging from 0.2 wt.% to 0.6 wt.% to isochronal and isothermal ageing at various temperatures for different times. It is observed that significant hardening takes place in the aged alloys due to the precipitation of scandium aluminides.

  20. EVOLUTION OF CHEMICAL CONDITIONS AND ESTIMATED PLUTONIUM SOLUBILITY IN THE RESIDUAL WASTE LAYER DURING POST-CLOSURE AGING OF TANK 18

    SciTech Connect

    Denham, M.

    2012-02-29

    This document updates the Eh-pH transitions from grout aging simulations and the plutonium waste release model of Denham (2007, Rev. 1) based on new data. New thermodynamic data for cementitious minerals are used for the grout simulations. Newer thermodynamic data, recommended by plutonium experts (Plutonium Solubility Peer Review Report, LA-UR-12-00079), are used to estimate solubilities of plutonium at various pore water compositions expected during grout aging. In addition, a new grout formula is used in the grout aging simulations and apparent solubilities of coprecipitated plutonium are estimated using data from analysis of Tank 18 residual waste. The conceptual model of waste release and the grout aging simulations are done in a manner similar to that of Denham (2007, Rev. 1). It is assumed that the pore fluid composition passing from the tank grout into the residual waste layer controls the solubility, and hence the waste release concentration of plutonium. Pore volumes of infiltrating fluid of an assumed composition are reacted with a hypothetical grout block using The Geochemist's Workbench{reg_sign} and changes in pore fluid chemistry correspond to the number of pore fluid volumes reacted. As in the earlier document, this results in three states of grout pore fluid composition throughout the simulation period that are termed Reduced Region II, Oxidized Region II, and Oxidized Region III. The one major difference from the earlier document is that pyrite is used to account for reducing capacity of the tank grout rather than pyrrhotite. This poises Eh at -0.47 volts during Reduced Region II. The major transitions in pore fluid composition are shown. Plutonium solubilities are estimated for discrete PuO2(am,hyd) particles and for plutonium coprecipitated with iron phases in the residual waste. Thermodynamic data for plutonium from the Nuclear Energy Agency are used to estimate the solubilities of the discrete particles for the three stages of pore fluid

  1. Effects of thermal aging on microstructures of low alloy steel-Ni base alloy dissimilar metal weld interfaces

    NASA Astrophysics Data System (ADS)

    Choi, Kyoung Joon; Kim, Jong Jin; Lee, Bong Ho; Bahn, Chi Bum; Kim, Ji Hyun

    2013-10-01

    In this study, the advanced instrumental analysis has been performed to investigate the effect of long-term thermal aging on the microstructural evolution in the fusion boundary region between weld metal and low alloy steel in dissimilar metal welds. A representative dissimilar weld mock-up made of Alloy 690-Alloy 152-A533 Gr. B was fabricated and aged at 450 °C for 2750 h. The micro- and nano-scale characterization were conducted mainly near in a weld root region by using optical microscopy, scanning electron microscopy, transmission electron microscopy, and three dimensional atom probe tomography. It was observed that the weld root was generally divided into several regions including dilution zone in the Ni-base alloy weld metal, fusion boundary, and heat-affected zone in the low alloy steel. A steep gradient was shown in the chemical composition profile across the interface between A533 Gr. B and Alloy 152. The precipitation of carbides was also observed along and near the fusion boundary of as-welded and aged dissimilar metal joints. It was also found that the precipitation of Cr carbides was enhanced by the thermal aging near the fusion boundary.

  2. Precipitation hardening and microstructure evolution of the Ti-7Nb-10Mo alloy during aging.

    PubMed

    Yi, Ruowei; Liu, Huiqun; Yi, Danqing; Wan, Weifeng; Wang, Bin; Jiang, Yong; Yang, Qi; Wang, Dingchun; Gao, Qi; Xu, Yanfei; Tang, Qian

    2016-06-01

    A biomedical β titanium alloy (Ti-7Nb-10Mo) was designed and prepared by vacuum arc self-consumable melting. The ingot was forged and rolled to plates, followed by quenching and aging. Age-hardening behavior, microstructure evolution and its influence on mechanical properties of the alloy during aging were investigated, using X-ray diffraction, transmission electron microscopy, tensile and hardness measurements. The electrochemical behavior of the alloy was investigated in Ringer's solution. The microstructure of solution-treated (ST) alloy consists of the supersaturated solid solution β phase and the ωath formed during athermal process. The ST alloy exhibits Young's modulus of 80 GPa, tensile strength of 774 MPa and elongation of 20%. The precipitation sequences during isothermal aging at different temperatures were determined as β+ωath→β+ωiso (144 h) at Taging=350-400 °C, β+ωath→β+ωiso+α→β+α at Taging=500°C, and β+ωath→β+α at Taging=600-650 °C, where ωiso forms during isothermal process. The mechanical properties of the alloy can be tailored easily through controlling the phase transition during aging. Comparing with the conventional Ti-6Al-4V alloy, the Ti-7Nb-10Mo alloy is more resistant to corrosion in Ringer's solution. Results show that the Ti-7Nb-10Mo alloy is promising for biomedical applications. PMID:27040253

  3. Influence of deformation ageing treatment on microstructure and properties of aluminum alloy 2618

    SciTech Connect

    Wang Jianhua Yi Danqing; Su Xuping; Yin Fucheng

    2008-07-15

    The effects of deformation ageing treatment (DAT) on the microstructure and properties of aluminum alloy 2618 were investigated. The alloy was subjected to deformation ageing treatment which included solution treating at 535 deg. C quenching into water at room-temperature, cold rolling (10%) and further ageing to peak hardness level at 200 deg. C. The electron microscopic studies revealed that the treatment affects the ageing characteristics and the coarsening of ageing phase (S') at elevated-temperature. The dislocation-precipitate tangles substructure couldn't be found in alloy 2618. The tensile and hardness tests showed that deformation-ageing treatment causes a significant improvement in tensile strength and hardness to alloy 2618 at room- and elevated-temperature.

  4. Sizing alpha emitting particles of aged plutonium on personal air sampler filters using CR-39 autoradiography.

    PubMed

    Richardson, R B; Hegyi, G; Starling, S C

    2003-01-01

    Methods have been developed to assess the size distribution of alpha emitting particles of reactor fuel of known composition captured on air sampler filters. The sizes of uranium oxide and plutonium oxide particles were determined using a system based on CR-39 solid-state nuclear track detectors. The CR-39 plastic was exposed to the deposited particles across a 400 microm airgap. The exposed CR-39 was chemically etched to reveal clusters of tracks radially dispersed from central points. The number and location of the tracks were determined using an optical microscope with an XY motorised table and image analysis software. The sample mounting arrangement allowed individual particles to be simultaneously viewed with their respective track cluster. The predicted diameters correlated with the actual particle diameters, as measured using the optical microscope. The efficacy of the technique was demonstrated with particles of natural uranium oxide (natUO2) of known size, ranging from 4 to 150 microm in diameter. Two personal air sampler (PAS) filters contaminated with actinide particles were placed against CR-39 and estimated to have size distributions of 0.8 and 1.0 microm activity median aerodynamic diameter (AMAD). PMID:14526944

  5. Opportunities in Plutonium Metallurgical Research

    SciTech Connect

    Schwartz, A J

    2006-12-19

    This is an exciting time to be involved in plutonium metallurgical research. Over the past few years, there have been significant advances in our understanding of the fundamental materials science of this unusual metal, particularly in the areas of self-irradiation induced aging of Pu, the equilibrium phase diagram, the homogenization of {delta}-phase alloys, the crystallography and morphology of the {alpha}{prime}-phase resulting from the isothermal martensitic phase transformation, and the phonon dispersion curves, among many others. In addition, tremendous progress has been made, both experimentally and theoretically, in our understanding of the condensed matter physics and chemistry of the actinides, particularly in the area of electronic structure. Although these communities have made substantial progress, many challenges still remain. This brief overview will address a number of important challenges that we face in fully comprehending the metallurgy of Pu with a specific focus on aging and phase transformations.

  6. Toward a Deeper Understanding of Plutonium

    SciTech Connect

    Schwartz, A J; Wolfer, W G

    2007-06-21

    computing power have enabled remarkable progress in our abilities to model many of the anomalous properties of Pu. This special issue of the Journal of Computer-Aided Materials Design highlights a number of these advances in the area of the aging of plutonium. This aging is a long-term process due to the slow radioactive decay with a long half-life of 24400 years for the major isotope of plutonium. The challenge then is to predict the changes in properties of plutonium and its alloys from experimental results of plutonium aged only for a few decades and from theory and computational models that are build on a thorough, first-principle understanding of all the complex phenomena displayed by this material. We hope that progress and success of this enterprise will guide other endeavors in Computer-Aided Materials Design and prediction of materials performance.

  7. Changes in delta-Plutonium due to self-irradiation aging observed by Continuous in-situ X-ray Scattering

    SciTech Connect

    Saw, C K; Chung, B W; Wall, M A

    2007-01-05

    The aging in plutonium is predominantly caused by its internal self-irradiation. The self-irradiation in Pu-239 is by the decay process of transmuting the Pu atom into uranium atom and emitting an {alpha}-particle. Most of the lattice damage comes from the uranium recoil resulting in Frenkel-type defects consisting of vacancies and self-interstitial atoms, helium in-growth and defect clusters and possibly even though it is not yet observed, the generation of voids. As part of the stockpile stewardship, it is important to understand the changes in the structure and microstructures and their correlations to the physical properties. Changes in the physical properties have a direct relationship to the quality of the structure, in terms of formation of defects and defect clustering, accumulation of voids, grain boundaries, phase changes and etc. which can adversely affect the stability of the material. These changes are very difficult to monitor because of the high activity of the sample, high atomic number making x-ray and synchrotron probe into the bulk very difficult (neutron probe is not feasible) and the long life time which normally requires decades to measure. In this paper we describe the development of an in-situ in-house transmission x-ray diffraction (XRD) experimental technique used to monitor the structural changes in these materials. This technique calls for a very thin sample of less that 2 mm and to accelerate the aging process due to self-irradiation, spiked alloy of 7.5 weight percent of Pu-238 is used. This is equivalent to roughly 17 times the normal rate of aging. Current results suggest that over a period of 2.8 equivalent years, an increase of 0.5% in unit cell parameter is observed. The increase appears to be an abrupt jump at about 1.1 equivalent years, brought about by the collapsing of the atoms from the interstitials to the lattice sites. Further data analysis is on the way.

  8. Aging Optimization of Aluminum-Lithium Alloy C458 for Application to Cryotank Structures

    NASA Technical Reports Server (NTRS)

    Sova, B. J.; Sankaran, K. K.; Babel, H.; Farahmand, B.; Rioja, R.

    2003-01-01

    Compared with aluminum alloys such as 2219, which is widely used in space vehicle for cryogenic tanks and unpressurized structures, aluminum-lithium alloys possess attractive combinations of lower density and higher modulus along with comparable mechanical properties. These characteristics have resulted in the successful use of the aluminum-lithium alloy 2195 (Al-1.0 Li-4.0 Cu-0.4 Mg-0.4 Ag-0.12 Zr) for the Space Shuttle External Tank, and the consideration of newer U.S. aluminum-lithium alloys such as L277 and C458 for future space vehicles. These newer alloys generally have lithium content less than 2 wt. % and their composition and processing have been carefully tailored to increase the toughness and reduce the mechanical property anisotropy of the earlier generation alloys such 2090 and 8090. Alloy processing, particularly the aging treatment, has a significant influence on the strength-toughness combinations and their dependence on service environments for aluminum-lithium alloys. Work at NASA Marshall Space Flight Center on alloy 2195 has shown that the cryogenic toughness can be improved by employing a two-step aging process. This is accomplished by aging at a lower temperature in the first step to suppress nucleation of the strengthening precipitate at sub-grain boundaries while promoting nucleation in the interior of the grains. Second step aging at the normal aging temperature results in precipitate growth to the optimum size. A design of experiments aging study was conducted for plate. To achieve the T8 temper, Alloy C458 (Al-1.8 Li-2.7 Cu-0.3 Mg- 0.08 Zr-0.3 Mn-0.6 Zn) is typically aged at 300 F for 24 hours. In this study, a two-step aging treatment was developed through a comprehensive 24 full factorial design of experiments study and the typical one-step aging used as a reference. Based on the higher lithium content of C458 compared with 2195, the first step aging temperature was varied between 175 F and 250 F. The second step aging temperatures was

  9. Aging characteristics of short glass fiber reinforced ZA-27 alloy composite materials

    NASA Astrophysics Data System (ADS)

    Sharma, S. C.; Girish, B. M.; Satish, B. M.; Kamath, R.

    1998-12-01

    Aging characteristics of short glass fiber reinforced ZA-27 alloy composite materials have been evaluated in the present study. The liquid metallurgy technique was used to fabricate the composites, in which preheated short glass fibers were introduced into the ZA-27 alloy melt above its liquidus temperature. The aging temperature employed was 125 °C for 6, 12,18, and 24 h. The aged alloy (no fibers) reached the peak hardness after 18 h, while the composites (regardless of filler content) reached the same hardness in 12 h. It is hypothesized that the aging treatment of a composite improves the strength of the interface between the short fibers and the matrix. This is confirmed by the tensile fractograph analysis, which indicates that at a given aging temperature, the composites aged for 18 h exhibit short fibers that remain attached to the metal matrix, while those aged for 6 h undergo debonding.

  10. Age hardening characteristics and mechanical behavior of Al-Cu-Li-Zr-In alloys

    NASA Technical Reports Server (NTRS)

    Wagner, John A.

    1989-01-01

    An investigation was conducted to determine the age-hardening response and cryogenic mechanical properties of superplastic Al-Cu-Li-Zr-In alloys. Two alloys with compositions Al-2.65Cu-2.17Li-O.13Zr (baseline) and Al-2.60Cu-2.34Li-0.16Zr-0.17In were scaled-up from 30 lb permanent mold ingots to 350 lb DC (direct chill) ingots and thermomechanically processed to 3.2 mm thick sheet. The microstructure of material which contained the indium addition was partially recrystallized compared to the baseline suggesting that indium may influence recrystallization behavior. The indium-modified alloy exhibited superior hardness and strength compared to the baseline alloy when solution-heat-treated at 555 C and aged at 160 C or 190 C. For each alloy, strength increased and toughness was unchanged or decreased when tested at - 185 C compared to ambient temperature. By using optimized heat treatments, the indium-modified alloy exhibited strength levels approaching those of the baseline alloy without deformation prior to aging. The increase in strength of these alloys in the T6 condition make them particularly attractive for superplastic forming applications where post-SPF parts cannot be cold deformed to increase strength.

  11. Plutonium microstructures. Part 1

    SciTech Connect

    Cramer, E.M.; Bergin, J.B.

    1981-09-01

    This report is the first of three parts in which Los Alamos and Lawrence Livermore National Laboratory metallographers exhibit a consolidated set of illustrations of inclusions that are seen in plutonium metal as a consequence of inherent and tramp impurities, alloy additions, and thermal or mechanical treatments. This part includes illustrations of nonmetallic and intermetallic inclusions characteristic of major impurity elements as an aid to identifying unknowns. It also describes historical aspects of the increased purity of laboratory plutonium samples, and it gives the composition of the etchant solutions and describes the etching procedure used in the preparation of each illustrated sample. 25 figures.

  12. Effects of Ce additions on the age hardening response of Mg–Zn alloys

    SciTech Connect

    Langelier, Brian Esmaeili, Shahrzad

    2015-03-15

    The effects of Ce additions on the precipitation hardening behaviour of Mg–Zn are examined for a series of alloys, with Ce additions at both alloying and microalloying levels. The alloys are artificially aged, and studied using hardness measurement and X-ray diffraction, as well as optical and transmission electron microscopy. It is found that the age-hardening effect is driven by the formation of fine precipitates, the number density of which is related to the Zn content of the alloy. Conversely, the Ce content is found to slightly reduce hardening. When the alloy content of Ce is high, large secondary phase particles containing both Ce and Zn are present, and remain stable during solutionizing. These particles effectively reduce the amount of Zn available as solute for precipitation, and thereby reduce hardening. Combining hardness results with thermodynamic analysis of alloy solute levels also suggests that Ce can have a negative effect on hardening when present as solutes at the onset of ageing. This effect is confirmed by designing a pre-ageing heat treatment to preferentially remove Ce solutes, which is found to restore the hardening capability of an Mg–Zn–Ce alloy to the level of the Ce-free alloy. - Highlights: • The effects of Ce additions on precipitation in Mg–Zn alloys are examined. • Additions of Ce to Mg–Zn slightly reduce the age-hardening response. • Ce-rich secondary phase particles deplete the matrix of Zn solute. • Hardening is also decreased when Ce is present in solution. • Pre-ageing to preferentially precipitate out Ce restores hardening capabilities.

  13. Enhancing Thermal Conductivity of Mg-Sn Alloy Sheet by Cold Rolling and Aging

    NASA Astrophysics Data System (ADS)

    Huang, Qiuyan; Tang, Aitao; Ma, Shida; Pan, Hucheng; Song, Bo; Gao, Zhengyuan; Rashad, Muhammad; Pan, Fusheng

    2016-06-01

    In present work, effect of cold rolling and aging on thermal conductivity (TC) of the as-extruded Mg-2Sn alloy was studied. Experimental results revealed that TC of as-extruded sheet decreases to value of ~105.4 W/m/K after 18% reduction rolling. TC increases with increase in aging time and regains the highest value of 126 W/m/K. Enhanced TC of cold-rolled Mg-Sn alloys is attributed to the defects annihilation, residual stress release, and precipitations. The more pronounced rolling reduction would induce more second-phase precipitations, and thus TC of the 18% rolled alloy is larger than that of 5% rolled alloys. Texture is also an important factor affecting thermal conductivity of Mg alloys, and double-peak texture is not beneficial for thermal transportation. The result would shed light on the novel design of highly conductive Mg sheet.

  14. Enhancing Thermal Conductivity of Mg-Sn Alloy Sheet by Cold Rolling and Aging

    NASA Astrophysics Data System (ADS)

    Huang, Qiuyan; Tang, Aitao; Ma, Shida; Pan, Hucheng; Song, Bo; Gao, Zhengyuan; Rashad, Muhammad; Pan, Fusheng

    2016-05-01

    In present work, effect of cold rolling and aging on thermal conductivity (TC) of the as-extruded Mg-2Sn alloy was studied. Experimental results revealed that TC of as-extruded sheet decreases to value of ~105.4 W/m/K after 18% reduction rolling. TC increases with increase in aging time and regains the highest value of 126 W/m/K. Enhanced TC of cold-rolled Mg-Sn alloys is attributed to the defects annihilation, residual stress release, and precipitations. The more pronounced rolling reduction would induce more second-phase precipitations, and thus TC of the 18% rolled alloy is larger than that of 5% rolled alloys. Texture is also an important factor affecting thermal conductivity of Mg alloys, and double-peak texture is not beneficial for thermal transportation. The result would shed light on the novel design of highly conductive Mg sheet.

  15. Plutonium controversy

    SciTech Connect

    Richmond, C.R.

    1980-01-01

    The toxicity of plutonium is discussed, particularly in relation to controversies surrounding the setting of radiation protection standards. The sources, amounts of, and exposure pathways of plutonium are given and the public risk estimated. (ACR)

  16. An Investigation into the Effect of Aging on the Forming Limit Diagram of 6063 Aluminum Alloy

    SciTech Connect

    Hosseini, S. M.; Hosseimpour, S. J.; Nourouzi, S.; Gorji, A. H.

    2011-01-17

    In this study, the effect of ageing on the forming limit diagram of a commercially available 6063 aluminum alloy has been investigated. For this purpose, initially the specimens have been aged at 200 deg. C and at various times. The hardness tests have been carried out and the hardness-aging time curve has been obtained for this alloy. Moreover, the mechanical properties were determined by tensile test. Then, the forming limit diagrams have been achieved by using the out-of-plane formability test method at four different conditions containing: annealed, under-aged, peak-aged, and over-aged. The results indicate that in comparing with the annealed condition the FLD{sub 0} decreases significantly from the under-aged condition to the peak-aged condition and increases slightly from the peak-aged condition to the over-aged condition.

  17. Effects of long-term aging on ductility and microstructure of Cb and Mo alloys

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.

    1977-01-01

    A program was conducted to determine if aging embrittlement occurs in columbium-base alloys C-103, Cb-1Zr, and Cb-752 or in a molybdenum alloy, Mo-TZM. Results showed that aging embrittlement does not occur in C-103, Cb-1Zr, or Mo-TZM during long-term (1000 hour) aging at temperatures in the range of 700-1025 C. In comparison, aging embrittlement occurred in the Cb-752 alloy after similar aging at 900 C. A critical combination of the solute additions W and Zr led to Zr segregation at grain boundaries during long-term aging which subsequently resulted in embrittlement as indicated by an increase in the ductile-brittle transition temperature from below -196 C to about -150 C.

  18. The development of dental alloys conserving precious metals: improving corrosion resistance by controlled ageing.

    PubMed

    Yasuda, K; Hisatsune, K; Ohta, M

    1983-03-01

    To determine the conditions which confer desirable mechanical properties and corrosion resistance upon dental alloys, age-hardening mechanism and the associated structural changes were studied by means of resistometric measurements, hardness tests, electron microscope observations and electron diffraction studies. Five commercial dental alloys, a high-gold content alloy, a low-gold alloy and three Au-Ag-Pd silver-based alloys and two experimental gold alloys, were examined. The structural and morphological changes which gave rise to age-hardening were classified into five types of phase transformation, i.e., (1) the formation of the AuCu I type superlattice and its twinning characterized by a stair-step mode, (2) the formation of the AuCu II type super-lattice with periodic antiphase domain structure, (3) the precipitation of the CuPd superlattice with fct structure analogous to the AuCu I type, (4) spinodal decomposition giving rise to a modulated structure and (5) the formation of the lamellar structure developed from grain boundaries by discontinuous precipitations. (1), (2) and (3) made a contribution to corrosion resistance superior to (4) and (5). A lamellar structure was prone to a high corrosion rate. The results obtained in this study are useful in predicting age-hardening characteristics and structural changes associated with corrosion, because the microstructural variation induced by ageing as well as nobility of alloys affects greatly their corrosion resistance. PMID:6574108

  19. Aging Optimization of Aluminum-Lithium Alloy L277 for Application to Cryotank Structures

    NASA Technical Reports Server (NTRS)

    Sova, B. J.; Sankaran, K. K.; Babel, H.; Farahmand, B.; Cho, A.

    2003-01-01

    Compared with aluminum alloys such as 2219, which is widely used in space vehicle for cryogenic tanks and unpressurized structures, aluminum-lithium alloys possess attractive combinations of lower density and higher modulus along with comparable mechanical properties and improved damage tolerance. These characteristics have resulted in the successful use of the aluminum-lithium alloy 2195 for the Space Shuttle External Tank, and the consideration of newer U.S. aluminum-lithium alloys such as L277 and C458 for future space vehicles. A design of experiments aging study was conducted for plate and a limited study on extrusions. To achieve the T8 temper, Alloy L277 is typically aged at 290 F for 40 hours. In the study for plate, a two-step aging treatment was developed through a design of experiments study and the one step aging used as a control. Based on the earlier NASA studies on 2195, the first step aging temperature was varied between 220 F and 260 F. The second step aging temperatures was varied between 290 F and 310 F, which is in the range of the single-step aging temperature. For extrusions, two, single-step, and one two-step aging condition were evaluated. The results of the design of experiments used for the T8 temper as well as a smaller set of experiments for the T6 temper for plate and the results for extrusions will be presented.

  20. Influence of plastic deformation and prolonged ageing time on microstructure of a Haynes 242 alloy.

    PubMed

    Dymek, S; Wróbel, M; Dollar, M; Blicharski, M

    2006-10-01

    The material used in this study was a commercial HAYNES alloy 242 with a nominal composition of Ni-25% Mo-8% Cr (in wt.%). In the standard heat treatment, the 242 alloy is annealed at a temperature between 1065 and 1095 degrees C and then water quenched. The ageing treatment is carried out at 650 degrees C for 24 h in order to develop the long-range-order strengthening. The alloy in the conventionally aged condition was additionally cold rolled to 50% reduction in thickness and subsequently subjected to prolonged ageing at 650 degrees C for 4000 h. The enhanced diffusion resulted in the decomposition of the Ni(2)(Mo,Cr) metastable phase into the stable Ni(3)Mo-based phase. The presence of the new stable phase increased the yield and tensile strengths but deteriorated the ductility of the alloy at both room and 650 degrees C temperatures. PMID:17100898

  1. Microstructural Evolution and Magnetic Properties of Aged CoNiGaAl Shape Memory Alloy

    NASA Astrophysics Data System (ADS)

    El-Bagoury, N.; Rashad, M. M.

    2016-05-01

    A study on the influence of aging heat treatment conditions at 823 K for 3 h, 24 h, and 120 h, on microstructure, martensitic transformation, and magnetic and mechanical properties of Co50Ni23Ga27- X Al X alloys ( X = 0 and 1 at.%) was performed by using x-ray diffraction (XRD) analysis, optical microscopy (OM), energy-dispersive spectrometer (EDS), differential scanning calorimeter (DSC), and vibrating sample magnetometer (VSM). The results show that the microstructure of both aged alloys consists of martensite and fcc second γ phase in addition to ordered cubic gamma prime ( γ') phase precipitates in martensite. The martensitic transformation temperature peak ( M p) elevates with prolonging aging time and decreasing valence electron concentration ( e v/ a). Saturation magnetization ( M s) decreases, whereas both remanence magnetization ( M r) and coercivity ( H c) increase with aging time. Meanwhile, the aging time enhances the hardness property ( H v) of the investigated alloys.

  2. Hydrogenation of deformable aluminum alloy semiproducts during water quenching and artificial aging

    NASA Astrophysics Data System (ADS)

    Antipin, V. P.; Tul'Pakova, R. V.

    2007-10-01

    The surface layers of rods made of magnesium-containing aluminum alloys are shown to undergo strong hydrogenation during water quenching. Hydrogenation is detected during vacuum heating after artificial aging (D16 alloy) or long-term storage (V95, AK4-1ch alloys). Very high hydrogen concentrations in the surface layers of semiproducts that appear in regions with a minimum cooling rate during quenching are likely to cause bubble formation on the surface of the heat-treated semiproducts. Compared to the V95 alloy, hydrogen dissolved in the AK4-1ch alloy rods behaves differently during air annealing. Specifically, hydrogen is rapidly absorbed by the degassed rods and is slowly extracted from the saturated rods. This behavior is most likely to be caused by hydrogen-ion entrapment by FeNiAl9 intermetallic particles.

  3. Precipitation Reactions in Age-Hardenable Alloys During Laser Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Jägle, Eric A.; Sheng, Zhendong; Wu, Liang; Lu, Lin; Risse, Jeroen; Weisheit, Andreas; Raabe, Dierk

    2016-03-01

    We describe and study the thermal profiles experienced by various age-hardenable alloys during laser additive manufacturing (LAM), employing two different manufacturing techniques: selective laser melting and laser metal deposition. Using scanning electron microscopy and atom probe tomography, we reveal at which stages during the manufacturing process desired and undesired precipitation reactions can occur in age-hardenable alloys. Using examples from a maraging steel, a nickel-base superalloy and a scandium-containing aluminium alloy, we demonstrate that precipitation can already occur during the production of the powders used as starting material, during the deposition of material (i.e. during solidification and subsequent cooling), during the intrinsic heat treatment effected by LAM (i.e. in the heat affected zones) and, naturally, during an ageing post-heat treatment. These examples demonstrate the importance of understanding and controlling the thermal profile during the entire additive manufacturing cycle of age-hardenable materials including powder synthesis.

  4. Effect of Pre-aging on Stress Corrosion Cracking of Spray-formed 7075 Alloy in Retrogression and Re-aging

    NASA Astrophysics Data System (ADS)

    Su, Rui-ming; Qu, Ying-dong; You, Jun-hua; de Li, Rong-

    2015-11-01

    The effects of pre-aging in retrogression and re-aging (RRA) treatment on microstructure, mechanical properties, and stress corrosion cracking (SCC) behavior of spray-formed 7075 aluminum alloy were investigated by tensile test, slow strain rate test, and transmission electron microscope. The results show that the under aging (120 °C for 16 h) as the pre-aging in RRA treatment can vastly improve the mechanical properties and the SCC resistance of the alloy, compared with early aging (120 °C for 8 h), peak aging (120 °C for 24 h), and over aging (120 °C for 32 h) treatments, the ultimate tensile strength of the alloy is 782 MPa, which is higher than that for peak aging or conventional RRA treatment; and the SCC resistance of the alloy is also excellent after RRA with under aging as pre-aging.

  5. Effect of Aging Treatments on the Mechanical and Corrosive Behaviors of Spray-Formed 7075 Alloy

    NASA Astrophysics Data System (ADS)

    Su, Rui-ming; Qu, Ying-dong; Li, Rong-de

    2014-11-01

    Mechanical properties, microstructure, exfoliation corrosion (EXCO), and intergranular corrosion (IGC) behaviors of the spray-formed 7075 aluminum alloy after T6, T73, retrogression (R), and re-aging (RRA) treatment, respectively, were studied by using tensile tester, transmission electron microscope, and scanning electron microscope. The results show that the T6 process can increase the ultimate tensile strength (UTS) up to 760 MPa, while it decreases the elongation, the EXCO, and the IGC resistance of the alloy. The T73 process can improve elongation, the EXCO, and the IGC resistance of the alloy. The corrosion resistance of the alloy can also be improved by R and RRA processes with retrogression times increase. The tiny precipitated phases distributed homogeneously in the matrix can increase the UTS. The close-connected discrete grain boundary phases (GBP) and the narrow precipitate free zones (PFZ) will lower the elongation, the EXCO, and the IGC resistance of the alloy. Contrarily, the discrete GBP and wide PFZ can improve the elongation, the EXCO, and the IGC resistance of the alloy. The EXCO and the IGC behaviors for the spray-formed 7075 alloy after different aging treatments have been established according to the standards of ASTM G34-2001 (2007) and ASTM G110-1992 (2009).

  6. Influence of homogenization and artificial aging heat treatments on corrosion behavior of Mg-Al alloys

    SciTech Connect

    Beldjoudi, T.; Fiaud, C.; Robbiola, L. . Lab. d'Etudes de la Corrosion)

    1993-09-01

    The influence of heat treatment on corrosion behavior of magnesium-aluminum (Mg-9Al) alloys was investigated by studying the electrochemical properties of Mg-9Al in the solution-treated (T4) and artificially aged (T6) conditions. The alloys' properties were compared to those of pure Mg, the intermetallic Mg[sub 17]Al[sub 12] phase, and different Mg-Al-based alloys (Mg-3Al, AZ91). The Mg-9Al alloy exhibited better corrosion resistance in the T6 condition than in the T4 condition because of the intermetallic Mg[sub 17]Al[sub 12] precipitates present n the T6 alloy. The mechanism responsible for this behavior was attributed to a more protective porous film on the T6 matrix alloy than on the T4 alloy. Addition of zinc did not modify these results. Localized corrosion testing showed the Mg-Al alloys were attacked preferentially in relation to magnesium silicide (Mg[sub 2]Si) precipitates which were characterized clearly using metallurgical examinations.

  7. Influence of 10 % Cold Rolling Reduction on Ageing Behaviour of Hot Rolled Al-Cu-Si-Mn-Mg Alloy

    NASA Astrophysics Data System (ADS)

    Ghosh, S. K.

    2014-09-01

    In the current study, the effect of 10 % cold rolling on the different ageing phenomena of Al-Cu-Si-Mn-Mg alloy was investigated. Both hot rolled and cold rolled alloys were subjected to both natural and artificial ageing processes. Hardness was measured to understand the change in the mechanical property of the alloy before and after rolling and also during ageing processes. From microscopy, it was evident that the cold rolling and subsequent ageing provided the alloy with a structure in which CuAl2 precipitates were uniformly distributed. The alloy exhibited the peak hardness value of 92 VHN after 2 days of natural ageing, whereas the cold deformed (10 %) alloy exhibited the higher peak hardness value of 139 VHN after 3 days of natural ageing. Peak hardness of the alloy reached 94 VHN, when hot rolled alloy was subjected to ageing at 250 °C for 1 h, whereas 10 % cold rolling followed by ageing (100 °C, 15 min) demonstrated accelerated and elevated hardening. The ageing behaviours thus obtained permit the alloy to provide a range of desirable combinations of strength and ductility for high strength weight saving applications.

  8. Influence of 10 % Cold Rolling Reduction on Ageing Behaviour of Hot Rolled Al-Cu-Si-Mn-Mg Alloy

    NASA Astrophysics Data System (ADS)

    Ghosh, S. K.

    2014-10-01

    In the current study, the effect of 10 % cold rolling on the different ageing phenomena of Al-Cu-Si-Mn-Mg alloy was investigated. Both hot rolled and cold rolled alloys were subjected to both natural and artificial ageing processes. Hardness was measured to understand the change in the mechanical property of the alloy before and after rolling and also during ageing processes. From microscopy, it was evident that the cold rolling and subsequent ageing provided the alloy with a structure in which CuAl2 precipitates were uniformly distributed. The alloy exhibited the peak hardness value of 92 VHN after 2 days of natural ageing, whereas the cold deformed (10 %) alloy exhibited the higher peak hardness value of 139 VHN after 3 days of natural ageing. Peak hardness of the alloy reached 94 VHN, when hot rolled alloy was subjected to ageing at 250 °C for 1 h, whereas 10 % cold rolling followed by ageing (100 °C, 15 min) demonstrated accelerated and elevated hardening. The ageing behaviours thus obtained permit the alloy to provide a range of desirable combinations of strength and ductility for high strength weight saving applications.

  9. 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.

  10. YIELD STRENGTH PREDICTION FOR RAPID AGE-HARDENING HEAT TREATMENT OF ALUMINUM ALLOYS

    SciTech Connect

    Yin, Hebi; Sabau, Adrian S; Ludtka, Gerard Michael; Skszek, Timothy; Niu, X

    2013-01-01

    A constitutive model has been developed to predict the yield strength aging curves for aluminum casting alloys during non-isothermal age-hardening processes. The model provides the specific relationship between the process variables and yield strength. Several aging heat treatment scenarios have been investigated using the proposed model, including two-step aging recipes. Two-step aging heat treatments involve a low temperature regime to promote nucleation of secondary phases and a second step at higher temperature for the growth of the secondary phases. The predicted results show that yield strength of approximately 300MPa might be obtained in shorter aging time, of approximately 30 minutes. Thus, better mechanical properties can be obtained by optimizing the time-temperature schedules for the precipitation hardening process of heat treatable aluminum alloys.

  11. Influence of aging on quench sensitivity effect of 7055 aluminum alloy

    SciTech Connect

    Liu, S.D. Zhang, X.M.; Chen, M.A.; You, J.H.

    2008-01-15

    The influence of aging on quench sensitivity effect of 7055 aluminum alloy was investigated by means of tensile properties and electrical conductivity tests. The microstructures were characterized by optical microscopy (OM) and transmission electron microscopy (TEM). Compared with single aging, duplex aging led to higher mechanical properties and lower electrical conductivity of the air quenched alloy, thus reduced the quench sensitivity effect. This was attributed to the elimination of negative effects due to loss of vacancies during slow quenching by duplex aging, which resulted in a higher density of stable G.P. zones in the matrix. Within the studied temperature 20-100 deg. C, a higher temperature pre-aging was favorable for reducing the quench sensitivity effect and the optimal duplex aging was 100 deg. C/24 h + 121 deg. C/24 h in this work.

  12. Metastability and Delta-Phase Retention in Plutonium Alloys Final Report of LDRD Project 01-ERD-029

    SciTech Connect

    Wong, J; Schwartz, A J; Blobaum, K M; Krenn, C R; Wall, M A; Wolfer, W G; Haslam, J J; Moore, K T

    2004-02-11

    The {delta} to {alpha}' phase transformation in Pu-Ga alloys is intriguing for both scientific and technological reasons. On cooling, the ductile fcc {delta}-phase transforms martensitically to the brittle monoclinic {alpha}'-phase at approximately -120 C (depending on composition). This exothermic transformation involves a 20% volume contraction and a significant increase in resistivity. The reversion of {alpha}' to {delta} involves a large temperature hysteresis beginning just above room temperature. In an attempt to better understand the underlying thermodynamics and kinetics responsible for these unusual features, we have investigated the {delta} {leftrightarrow} {alpha}' phase transformations in a Pu-0.6 wt% Ga alloy using a combination of experimental and modeling techniques.

  13. Aging Optimization of Aluminum-Lithium Alloy C458 for Application to Cryotank Structures

    NASA Technical Reports Server (NTRS)

    Sova, B. J.; Sankaran, K. K.; Babel, H.; Farahmand, B.; Rioja, R.

    2003-01-01

    Compared with aluminum alloys such as 2219, which is widely used in space vehicle for cryogenic tanks and unpressurized structures, aluminum-lithium alloys possess attractive combinations of lower density and higher modulus along with comparable mechanical properties. These characteristics have resulted in the successful use of the aluminum-lithium alloy 2195 (Al-1.0 Li-4.0 Cu-0.4 Mg-0.4 Ag-0.12 Zr) for the Space Shuttle External Tank, and the consideration of newer U.S. aluminum-lithium alloys such as L277 and C458 for future space vehicles. These newer alloys generally have lithium content less than 2 wt. % and their composition and processing have been carefully tailored to increase the toughness and reduce the mechanical property anisotropy of the earlier generation alloys such 2090 and 8090. Alloy processing, particularly the aging treatment, has a significant influence on the strength-toughness combinations and their dependence on service environments for aluminum-lithium alloys. Work at NASA Marshall Space Flight Center on alloy 2195 has shown that the cryogenic toughness can be improved by employing a two-step aging process. This is accomplished by aging at a lower temperature in the first step to suppress nucleation of the strengthening precipitate at sub-grain boundaries while promoting nucleation in the interior of the grains. Second step aging at the normal aging temperature results in precipitate growth to the optimum size. A design of experiments aging study was conducted for plate. To achieve the T8 temper, Alloy C458 (Al-1.8 Li-2.7 Cu-0.3 Mg-0.08 Zr-0.3 Mn-0.6 Zn) is typically aged at 300F for 24hours. In this study, a two-step aging treatment was developed through a comprehensive 2(exp 4) full factorial design of experiments study and the typical one-step aging used as a reference. Based on the higher lithium content of C458 compared with 2195, the first step aging temperature was varied between 175F and 250F. The second step aging temperatures was

  14. Age Hardening Kinetics in 7xxx Type (Al-Mg-Zn) Alloys

    SciTech Connect

    Vevecka-Priftaj, A.; Lamani, E.; Fjerdingen, J.; Langsrud, Y.; Gjoennes, J.; Hansen, V.

    2007-04-23

    Age hardening in industrial 7xxx alloys at the temperature 100 deg. and 150 deg. C up to 144 hrs, after solid solution treatments at 450 deg. and 550 deg. C, has been followed by measurements of Vickers hardness, scanning and transmission electron microscopy. The influence of silicon on phase and kinetic of age hardening zones and precipitates has been studied. High iron and silicon content increase the number of primary particle in the alloy. Size distribution of {eta}'-precipitates has been determined.

  15. Strain ageing and yield plateau phenomena in {gamma}-TiAl based alloys containing boron

    SciTech Connect

    Cheng, T.T.; Bate, P.S.; Botten, R.R.; Lipsitt, H.A.

    1999-01-08

    There has been considerable interest over the past few years in {gamma}-TiAl based alloys since they offer a combination of low density and useful mechanical properties at temperatures higher than those possible with conventional titanium alloys. However, there are still serious limitations to their use in engineering components due to their limited ductility and fracture toughness. Much of the recent work has been focused on improving the room temperature ductility of these materials, and a significant part of the work has been involved with studying the effects of thermo-mechanical processing (TMP) and alloying. One of the alloying additions which has received much attention is boron. Addition of boron ({ge}0.5 at.%) leads to refined as-cast grain structures and can increase the strength and ductility of these alloys. If boron does segregate to grain boundaries, it would be expected that segregation would also occur at dislocations, which can result in solute locking and yield point phenomena. Nakano and Umakoshi`s results show some signs of this, with regions of distinct upward curvature in stress-strain curves for boron-containing material, although the flow stress was always increasing with strain. Evidence of strain ageing in TiAl alloys containing boron has also been reported by Wheeler et al., and the work reported here also suggests that boron can act to produce solute locking of glide dislocations in a different class of near {gamma}-TiAl alloys.

  16. Age hardening and creep resistance of cast Al–Cu alloy modified by praseodymium

    SciTech Connect

    Bai, Zhihao; Qiu, Feng; Wu, Xiaoxue; Liu, Yingying; Jiang, Qichuan

    2013-12-15

    The effects of praseodymium on age hardening behavior and creep resistance of cast Al–Cu alloy were investigated. The results indicated that praseodymium facilitated the formation of the θ′ precipitates during the age process and improved the hardness of the Al–Cu alloy. Besides, praseodymium resulted in the formation of the Al{sub 11}Pr{sub 3} phase in the grain boundaries and among the dendrites of the modified alloy. Because of the good thermal stability of Al{sub 11}Pr{sub 3} phase, it inhibits grain boundary migration and dislocation movement during the creep process, which contributes to the improvement in the creep resistance of the modified alloy at elevated temperatures. - Highlights: • Pr addition enhances the hardness and creep resistance of the Al–Cu alloy. • Pr addition facilitates the formation of the θ′ precipitates. • Pr addition results in the formation of the Al11Pr3 phase in the Al–Cu alloy.

  17. Strengthening of Cu–Ni–Si alloy using high-pressure torsion and aging

    SciTech Connect

    Lee, Seungwon; Matsunaga, Hirotaka; Sauvage, Xavier; Horita, Zenji

    2014-04-01

    An age-hardenable Cu–2.9%Ni–0.6%Si alloy was subjected to high-pressure torsion. Aging behavior was investigated in terms of hardness, electrical conductivity and microstructural features. Transmission electron microscopy showed that the grain size is refined to ∼ 150 nm and the Vickers microhardness was significantly increased through the HPT processing. Aging treatment of the HPT-processed alloy led to a further increase in the hardness. Electrical conductivity is also improved with the aging treatment. It was confirmed that the simultaneous strengthening by grain refinement and fine precipitation is achieved while maintaining high electrical conductivity. Three dimensional atom probe analysis including high-resolution transmission electron microscopy revealed that nanosized precipitates having compositions of a metastable Cu{sub 3}Ni{sub 5}Si{sub 2} phase and a stable NiSi phase were formed in the Cu matrix by aging of the HPT-processed samples and these particles are responsible for the additional increase in strength after the HPT processing. - Highlights: • Grain refinement is achieved in Corson alloy the size of ∼150nm by HPT. • Aging at 300°C after HPT leads to further increase in the mechanical property. • Electrical conductivity reaches 40% IACS after aging for 100 h. • 3D-APT revealed the formation of nanosized-precipitates during aging treatment. • Simultaneous hardening in both grain refinement and precipitation is achieved.

  18. Microstructural evolution during aging of an Al-Cu-Li-Ag-Mg-Zr alloy

    NASA Technical Reports Server (NTRS)

    Kumar, K. S.; Brown, S. A.; Pickens, Joseph R.

    1991-01-01

    Alloys in the Al-Cu-Li Ag-Mg subsystem were developed that exhibit desirable combinations of strength and ductility. These Weldalite (trademark) alloys, are unique for Al-Cu-Li alloys in that with or without a prior cold stretching operation, they obtain excellent strength-ductility combinations upon natural and artificial aging. This is significant because it enables complex, near-net shape products such as forgings and super plastically formed parts to be heat treated to ultra-high strengths. On the other hand, commercial extrusions, rolled plates and sheets of other Al-Cu-Li alloys are typically subjected to a cold stretching operation before artificial aging to the highest strength tempers to introduce dislocations that provide low-energy nucleation sites for strengthening precipitates such as the T(sub 1) phase. The variation in yield strength (YS) with Li content in the near-peak aged condition for these Weldalite (trademark) alloys and the associated microstructures were examined, and the results are discussed.

  19. Precipitation in dilute Cu-Cr alloys; The effects of phosphorus impurities and aging procedure

    SciTech Connect

    Luo, C.P.; Dahmen, U.; Witcomb, M.J.; Westmacott, K.H. )

    1992-02-15

    This paper reports that precipitation in dilute Cu-Cr alloys has been studied extensively in part because this alloy can be used as a model system for the investigation of the crystallography and interfaces in FCC-BCC phase transformations. Hall et al. first reported needle- or lath-shaped Cr-rich precipitates with a {l brace}335{r brace}{sub f} habit plane and a variable orientation relationship ranging from Nishiyama-Wasserman (N-W) to Kurdjumov-Sachs (K-S). Hall and Aaronson later confirmed their early findings. Weatherly et al. however, found a constant K-S orientation relationship for this alloy system and a preferred growth direction of {l angle}651{r angle}{sub f} for the needle-shaped precipitates. The variation of the orientation relationship and its potential effect on the precipitate morphology and interface structure have become key points in studying the precipitate crystallography of this alloy system. Dahmen et al. attributed the variation of the orientation relationship to the different quenching and aging conditions applied to the alloy; a direct quench from the solutionizing to the aging temperature employed by Hall et al. would result in a heterogeneous nucleation and hence a variation in the precipitation behavior, while the water quench and aging procedure utilized by Weatherly et al, would facilitate homogeneous nucleation and produce a constant crysallography.

  20. Effect of Thermal Aging on the Corrosion Behavior of Wrought and Welded Alloy 22

    SciTech Connect

    R.B. Rebak; T.S. Edgecumbe Summers; T. Lian

    2002-07-02

    Alloy 22 (UNS N06022) is a candidate material for the external wall of the high level nuclear waste containers for the potential repository site at Yucca Mountain. In the mill-annealed (MA) condition, Alloy 22 is a single face centered cubic phase. When exposed to temperatures on the order of 600 C and above for times higher than 1 h, this alloy may develop secondary phases that are brittle and offer a lower corrosion resistance than the MA condition. The objective of this work was to age Alloy 22 at temperatures between 482 C and 800 C for times between 0.25 h and 3,000 h and to study the corrosion performance of the resulting material. Aging was carried out using wrought specimens as well as gas tungsten arc welded (GTAW) specimens. The corrosion performance was characterized using standard immersion tests in aggressive acidic solutions and electrochemical tests in multi-component solutions. Results show that, in general, in aggressive acidic solutions the corrosion rate increased as the aging temperature and aging time increased. However, in multi ionic environments that could be relevant to the potential Yucca Mountain site, the corrosion rate of aged material was the same as the corrosion rate of the MA material.

  1. Effect of Thermal Aging on the Corrosion Behavior of Wrought and Welded Alloy 22

    SciTech Connect

    Rebak, R.B.; Edgecumbe, T.S.; Lian, T.; Carranza, R.M.; Dillman, J.R.; Corbin, T.; Crook, P.

    2002-01-02

    Alloy 22 (UNS N06022) is a candidate material for the external wall of the high level nuclear waste containers for the potential repository site at Yucca Mountain. In the mill-annealed (MA) condition, Alloy 22 is a single face centered cubic phase. When exposed to temperatures on the order of 600 C and above for times higher than 1 h, this alloy may develop secondary phases that are brittle and offer a lower corrosion resistance than the MA condition. The objective of this work was to age Alloy 22 at temperatures between 482 C and 800 C for times between 0.25 h and 3,000 h and to study the corrosion performance of the resulting material. Aging was carried out using wrought specimens as well as gas tungsten arc welded (GTAW) specimens. The corrosion performance was characterized using standard immersion tests in aggressive acidic solutions and electrochemical tests in multi-component solutions. Results show that, in general, in aggressive acidic solutions the corrosion rate increased as the aging temperature and aging time increased. However, in multi ionic environments that could be relevant to the potential Yucca Mountain site, the corrosion rate of aged material was the same as the corrosion rate of the MA material.

  2. Influence of aging temperature on the structure and mechanical properties of titanium alloy VT22 subjected to helical rolling

    NASA Astrophysics Data System (ADS)

    Mishin, I. P.; Naydenkin, E. V.; Ratochka, I. V.; Lykova, O. N.; Balushkina, M. A.

    2015-10-01

    The structure and mechanical properties of titanium alloy VT22 after helical rolling and subsequent aging was investigated. It is shown that the treatment leads to the formation of ultra-fine grain/subgrain structure in the alloy. The subsequent aging increases the ultimate strength and yield strength to 1640 and 1590 MPa respectively, while saving satisfactory plasticity (δ > 5%).

  3. Plutonium inventories for stabilization and stabilized materials

    SciTech Connect

    Williams, A.K.

    1996-05-01

    The objective of the breakout session was to identify characteristics of materials containing plutonium, the need to stabilize these materials for storage, and plans to accomplish the stabilization activities. All current stabilization activities are driven by the Defense Nuclear Facilities Safety Board Recommendation 94-1 (May 26, 1994) and by the recently completed Plutonium ES&H Vulnerability Assessment (DOE-EH-0415). The Implementation Plan for accomplishing stabilization of plutonium-bearing residues in response to the Recommendation and the Assessment was published by DOE on February 28, 1995. This Implementation Plan (IP) commits to stabilizing problem materials within 3 years, and stabilizing all other materials within 8 years. The IP identifies approximately 20 metric tons of plutonium requiring stabilization and/or repackaging. A further breakdown shows this material to consist of 8.5 metric tons of plutonium metal and alloys, 5.5 metric tons of plutonium as oxide, and 6 metric tons of plutonium as residues. Stabilization of the metal and oxide categories containing greater than 50 weight percent plutonium is covered by DOE Standard {open_quotes}Criteria for Safe Storage of Plutonium Metals and Oxides{close_quotes} December, 1994 (DOE-STD-3013-94). This standard establishes criteria for safe storage of stabilized plutonium metals and oxides for up to 50 years. Each of the DOE sites and contractors with large plutonium inventories has either started or is preparing to start stabilization activities to meet these criteria.

  4. Effect of aging on mechanical properties of aluminum-alloy rivets

    NASA Technical Reports Server (NTRS)

    Roop, Frederick C

    1941-01-01

    Curves and tabular data present the results of strength tests made during and after 2 1/2 years of aging on rivets and rivet wire of 3/16-inch nominal diameter. The specimens were of aluminum alloy: 24s, 17s, and a17s of the duralumin type and 53s of the magnesium-silicide type.

  5. Effect of aging on mechanical properties of aluminum-alloy rivets

    NASA Technical Reports Server (NTRS)

    Roop, Frederick C

    1941-01-01

    Curves and tabular data present the results of strength tests made during and after 2 1/2 years of aging on rivets and rivet wire of 3/16-inch nominal diameter. The specimens were of aluminum alloy: 24S, 17S, and A17S of the duralumin type and 53S of the magnesium-silicide type.

  6. Effect of Isothermal Aging on the Physical Properties of Mn53Ni23Ga22 Ferromagnetic Shape Memory Alloy

    NASA Astrophysics Data System (ADS)

    Dong, G. F.; Gao, Z. Y.

    2016-07-01

    The effect of isothermal aging on the physical properties of Mn53Ni25Ga22 alloy has been systematically investigated. The results showed that the (Mn,Ni)4Ga-type precipitates are observed in all isothermal aged samples. However, second phases tended to align into grains and had two preferred orientations. The martensitic transformation temperatures decreased remarkably with the increase of aging time, while structure of the alloy gradually changed from five-layer tetragonal martensite to austenite. Additionally, we found that the appropriate aging-treated alloys can significantly enhance the saturation magnetization of Mn53Ni25Ga22 alloy. However, the Curie temperatures decreased remarkably with increased aging time due to the variation of the composition of the alloy.

  7. Strain-age cracking in Rene 41 alloy

    NASA Technical Reports Server (NTRS)

    Prager, M.; Thompson, E. G.

    1969-01-01

    Weldability test determines the effects of material and process variables on the occurrence of strain-age cracking, and demonstrates effective and practical means for its reduction. Studies consist of tensile, impact, and stress-rupture tests.

  8. [Study on the age-hardenable silver alloy (3 rd report). III. On the ageing process of dental Ag-Pd-Cu-Au alloy (author's transl)].

    PubMed

    Ota, M; Hisatsune, K; Yamane, M

    1975-05-01

    The precipitation hardening process of a dental silver base alloy, Ag-28 Pd-10 Cu-12 wt % Au, was studied by means of X-ray diffraction, hardness measurement and metallographic observations. After solution treatment at 900 degrees C for 30 min, specimens were subjected to anisothermal annealing at the rate of 1 degrees C/min. PdCu ordered phase and alpha2 solid solution (Ag rich phase) precipitated hetelogeneously at the grain boundaries and then grew up into each grain. Drastic increase in hardness was recognized with the spread of nodular region. Electron microscopic observation of these precipitates showed very fine lamellar structure. It is concluded that the age hardening of this alloy could be attributed to this grain boundary precipitation and the softening at the overaged stage to the second grain boundary reaction which produced very coarse lamellar structure. PMID:1058263

  9. Effects of long-term aging on ductility of the columbium alloys C-103, Cb-1Zr, and Cb-752 and the molybdenum alloy Mo-TZM

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.

    1975-01-01

    A program was conducted to determine if aging embrittlement occurs in the columbium alloys C-103, CB-1Zr, and Cb-752 or in the molybdenum alloy Mo-TZM. Results showed that aging embrittlement does not occur in C-103, Cb-1Zr, or Mo-TZM during long-term (1000 hr) aging at temperatures in the range 700 to 1025 C. In contrast, aging embrittlement did occur in the Cb-752 alloy after similar aging at 900 C. A critical combination of the solute additions W and Zr in Cb-752 led to Zr segregation at grain boundaries during long-term aging. This segregation subsequently resulted in embrittlement as indicated by an increase in the ductile-brittle transition temperature from below -1960 C to about -150 C.

  10. Microstructure and Mechanical Instability of Water-Quenched U-6wt% Nb Alloy Affected by Long-Term Aging

    SciTech Connect

    Hsiung, L; Zhou, J

    2005-12-06

    A combinative approach of microhardness testing, tensile testing, and TEM microstructural analysis was employed to study the microstructure and mechanical instability of a water-quenched U-6wt.% Nb (WQ-U6Nb) alloy subjected to different aging schedules including artificial aging at 200 C, 15-year natural aging at ambient temperatures, and 15-year natural aging followed by accelerative aging at 200 C. The changes in mechanical property during and after the aging processes were examined using microhardness and tensile-testing methods. During the early stages of artificial aging at 200 C, the microhardness of WQ-U6Nb alloy increased, i.e., age hardening, as a result of the development of nanoscale modulation caused by spinodal decomposition. Coarsening of the modulated structure occurred after a prolonged aging at 200 C for 16 hours, and it led to a decrease of microhardness, i.e., age softening. Phase instability was also found to occur in WQ-U6Nb alloy that was subjected to a 15-year natural aging at ambient temperatures. The formation of partially ordered domains resulting from a spinodal modulation with an atomic-scale wavelength rendered the appearance of swirl-shape antiphase domain boundaries (APBs) observed in TEM images. Although it did not cause a significant change in microhardness, 15-year natural aging has dramatically affected the aging mechanisms of the alloy isothermally aged at 200 C. Microhardness values of the NA alloy continuously increased and no age softening was found after isothermal aging at 200 C for 96 hours as a result of the phase decomposition of partially ordered domains into Nb-depleted {alpha} phase and Nb-enriched U{sub 3}Nb ordered phase in the alloy. It is concluded that the long-term natural aging changes the transformation pathway of WQ-U6Nb, and it leads to order-disorder transformation, precipitation hardening, and ductility embrittlement of WQ-U6Nb alloy.

  11. Precipitation in a Cu–Cr–Zr–Mg alloy during aging

    SciTech Connect

    Cheng, J.Y. Shen, B.; Yu, F.X.

    2013-07-15

    The precipitation processes in a Cu-0.69Cr-0.10Zr-0.02Mg alloy aged at 450 °C and 550 °C have been investigated by transmission electron microscopy and high resolution transmission electron microscopy. The precipitation sequence in this alloy aged at 450 °C is: supersaturated solid solution → Guinier–Preston zone (fcc Cr-rich phase) → ordered fcc Cr-rich phase → ordered bcc Cr-rich phase. The precipitation sequence in this alloy aged at 550 °C is: supersaturated solid solution → ordered fcc Cr-rich phase → ordered bcc Cr-rich phase. In the evolution of decomposition, the orientation relationship between the precipitates and the Cu matrix changes from cube-on-cube to Nishiyama–Wassermann orientation. The ordering of Cr-rich precipitates facilitates the formation of the bcc precipitates and promotes the development of Nishiyama–Wassermann orientation. - Highlights: • Two different precipitation sequences in the Cu–Cr–Zr–Mg alloy are proposed. • The changes in orientation relationship of the precipitates are presented. • The roles of ordering and coherent interface of the precipitates are discussed.

  12. KINETIC STUDY OF AGING IN A URANIUM-TITANIUM EUTECTOID ALLOY USING THERMOELECTRIC POWER MEASUREMENT

    SciTech Connect

    Herrmann, B.; Gelbstein, Y.; Kimmel, G.; Landau, A.

    2008-02-28

    Considerable attention has been given to the study of microstructure evolution and mechanical properties of dilute U-Ti alloys. A typical procedure of heat treatment of the eutectoid uranium-titanium alloy consists of solution treatment in the {gamma} phase, obtaining of soft {alpha}{sup '} martensitic metastable structure by water quenching to room temperature and precipitation hardening by aging at 300-550 deg. C. Depending on employed temperature and time the aging results in GP zone formation through the precipitation reaction {alpha}{sup '}{yields}{alpha}+{delta}. The {delta} phase is a hexagonal U{sub 2}Ti intermetallic compound, responsible for the significant increase in the level of the micro-strain in the metastable {alpha}{sup '} matrix. Thermoelectric power (TEP) measurements have recently gained a growing attention for the characterization of metallurgical properties in steels and other alloys. These measurements, which are based on the Seebeck effect, are sensitive to changes in the electronic structure of the material as result of various metallurgical processes. In the current research, TEP measurement technique was applied as a non destructive assessment technique to characterize the aging kinetics of the quenched uranium-titanium binary alloy. Good correlation has been found between measured TEP, micro-strain evolution, as obtained by using XRD, and hardness values at different heat treatment stages. A reasonable explanation of the correlation between the crystallography changes, micro-strain, TEP measurements and properties is presented.

  13. Atomic structure of Cu-10. 9 at % Be alloys in the early stages of aging

    SciTech Connect

    Koo, Y.M.

    1987-01-01

    Diffuse x-ray scattering was employed to investigate the local atomic structure and static strains in a single crystal of a Cu-10.9 at. % Be alloy in the early stages of aging. In addition to these experiments, neutron elastic and inelastic scattering were obtained to investigate the phonon properties in the as-quenched state of this alloy. In the as-quenched state, there is a nearly regular array of small ellipsoidal Be clusters aligned along <100> directions (This produces the tweed contrast seen in TEM). The density of these clusters is 7.5 x 10/sup 26//m/sup 3/. The diffuse streaks seen in electron diffraction patterns are due largely to thermal diffuse scattering. Phonon-dispersion curves show no large differences from those of pure copper, except at (xi xi xi)/sub T/ zone boundary, where there is softening. This difference may be due to a Kohn anomaly. The elastic anisotropy of this alloy increases considerably with alloying, which probably leads to the plate-like GP zone morphology in subsequent aging treatments. The structure of the GP zones is a mixture of Be-rich single- and multi-layered zones. As aging proceeds, the zones grow in thickness.

  14. Aging of an aluminum alloy resulting from variations in the cooling rate

    SciTech Connect

    Cavazos, J.L.; Colas, R.

    1999-10-01

    The effect that the rate of cooling after solubilization exerts on the aging behavior of an aluminum heat treatable alloy was studied. Bars of the alloy were heated in a box furnace for solubilization, and after this was achieved they were cooled to room temperature by placing one end in a shallow tank of water. Thermal evolution along the bar was registered with the aid of thermocouples connected to a PC-based data logging system. Small samples were cut from the bars and aged for different times and temperatures. Results from microhardness tests indicate that peak hardness, at a given aging temperature, augments with the increase of the cooling rate until a certain value is achieved, above which the hardness remains constant. This feature was found to be due to precipitation taking place at the lower cooling rates.

  15. Isothermal age-hardening behaviour in a Au-1.6 wt% Ti alloy.

    PubMed

    Kim, H I; Seol, H J; Bae, D H; Shim, J Y; Takada, Y; Okuno, O

    1999-03-01

    This study describes research with a view to developing a new age-hardenable, high-carat dental gold alloy with better biocompatibility by addition of a small quantity of titanium to gold. The relationship between isothermal age-hardening and phase transformation of the Au-1.6 wt% Ti alloy was investigated by means of hardness testing, X-ray diffraction study, scanning electron microscopic observation and energy dispersive spectroscopy. The hardening in the initial stage of ageing seemed to be attributable to the continuous precipitation of the Au4Ti ordered phase in the supersaturated alpha solid solution matrix. The overaging with softening was attributed mainly to the formation of precipitates at the grain boundaries, which grew to bright lamellae and seemed to be composed of the Au4Ti phase. PMID:10786146

  16. Plutonium pyrophoricity

    SciTech Connect

    Stakebake, J.L.

    1992-06-02

    A review of the published literature on ignition and burning of plutonium metal was conducted in order to better define the characteristic of pyrophoric plutonium. The major parameter affecting ignition is the surface area/mass ratio of the sample. Based on this parameter, plutonium metal can be classified into four categories: (1) bulk metal, (2) film and foils, (3) chips and turnings, and (4) powder. Other parameters that can alter the ignition of the metal include experimental, chemical, physical, and environmental effects. These effects are reviewed in this report. It was concluded from this review that pyrophoric plutonium can be conservatively defined as: Plutonium metal that will ignite spontaneously in air at a temperature of 150{degrees}C or below in the absence of external heat, shock, or friction. The 150{degrees}C temperature was used to compensate for the self-heating of plutonium metal. For a practical definition of whether any given metal is pyrophoric, all of the factors affecting ignition must be considered.

  17. Microstructure and aging behavior of conventional and nanocrystalline aluminum-copper-magnesium alloys with scandium additions

    NASA Astrophysics Data System (ADS)

    Zuniga, Alejandro

    The influence of small amounts of scandium (0.15 and 0.3 wt.%) on the microstructure, aging behavior and mechanical properties of 2618 (Al-Cu-Mg-Fe-Ni) and C416 (Al-Cu-Mg-Ag-Mn) alloys was studied. It was observed the overall precipitation sequence and the general morphology of the aging curve were not affected by the addition of small amounts of Sc. It was also observed that a separate population of small Al3Sc particles improved the aging response and mechanical properties of low-Cu, low-Sc Al-Cu-Mg alloys, while the formation of Al5-8Cu7-4Sc particles resulted in a decrease of the mechanical properties in high-Cu Sc-containing alloys. The Sc-modified with the best aging response (2618 + 0.15 % Sc) was cryomilled in order to produce Al-Cu-Mg-Fe-Ni-Sc nanocrystalline powders. Bulk nanocrystalline samples were consolidated from the cryomilled powder using three different techniques: hot isostatic pressing and extrusion, spark plasma sintering, cold spraying. The influence of consolidation technique on the microstructure, aging behavior and mechanical properties was analyzed. The extruded and spark plasma sintered Al-Cu-Mg-Fe-Ni-Sc nanocrystalline samples presented a bimodal grain structure consisting of coarse-grained regions located at the inter-particle region, and nanocrystalline regions at the particle interiors. The aging behavior of the nanocrystalline Al-Cu-Mg-Fe-Ni-Sc alloy was characterized by softening instead of hardening. This behavior was rationalized on the basis of changes in the precipitation processes that occur in the nanocrystalline state. On the other hand, the cold spray process promoted the formation of truly nanocrystalline coatings. The mechanisms influencing the coating formation of conventional and nanocrystalline Al-Cu-Mg-Fe-Ni-Sc samples were analyzed.

  18. Lattice Changes in Shape Memory CuZnAl Alloys on Aging at Room Temperature

    NASA Astrophysics Data System (ADS)

    Çakmak, Seyfettýn; Artunç, Ekrem; Kayali, Nejdet; Adigüzel, Osman

    2001-09-01

    The aging behavior of CuZnAl martensites (Cu-21.62 wt.% Zn-5.68 wt.% Al and Cu-24.98 wt.% Zn-4.43 wt.% Al) at about 297 K was studied by analyzing diffraction line profiles obtained by X-ray diffractometry. For the alloys, the change of the lattice parameters and the tetragonality associated with the aging time at room temperature were investigated. The habit planes versus the aging time at room temperature were calculated using the De Vos-Aernoundt-Delaey model, based on the crystallographic theory of Wechsler-Lieberman-Read(WLR), and from the DO3→ 18R martensite transformation theory.

  19. Effect of a prior stretch on the aging response of an Al-Cu-Li-Ag-Mg-Zr alloy

    NASA Technical Reports Server (NTRS)

    Kumar, K. S.; Brown, S. A.; Pickens, Joseph R.

    1991-01-01

    Recently, a family of Al-Cu-Li alloys containing minor amounts of Ag, Mg, and Zr and having desirable combinations of strength and toughness were developed. The Weldalite (trademark) alloys exhibit a unique characteristic in that with or without a prior stretch, they obtain significant strength-ductility combinations upon natural and artificial aging. The ultra-high strength (approximately 690 MPa yield strength) in the peak-aged tempers (T6 and T8) were primarily attributed to the extremely fine T(sub 1) (Al2CuLi) or T(sub 1)-type precipitates that occur in these alloys during artificial aging, whereas the significant natural aging response observed is attributed to strengthening from delta prime (Al3Li) and GP zones. In recent work, the aging behavior of an Al-Cu-Li-Ag-Mg alloy without a prior stretch was followed microstructurally from the T4 to the T6 condition. Commercial extrusions, rolled plates, and sheets of Al-Cu-Li alloys are typically subjected to a stretching operation before artificial aging to straighten the extrusions and, more importantly, introduce dislocations to simulate precipitation of strengthening phases such as T(sub 1) by providing relatively low-energy nucleation sites. The goals of this study are to examine the microstructure that evolves during aging of an alloy that was stretch after solution treatment and to compare the observations with those for the unstretched alloy.

  20. Characteristics of laser beam welds of age-hardenable 6061-T6 aluminum alloy

    NASA Astrophysics Data System (ADS)

    Hirose, Akio; Kobayashi, Kojiro F.

    2003-03-01

    Laser beam welding is attractive for joining age-hardenable aluminum alloys, because its low over-all heat input results in a narrow weld heat affected zone (HAZ), where softening caused by dissolution of age precipitates occurs. In the present work, 1mm-thick 6061-T6 aluminum alloy plates were welded using a 2.5 kW CO2 laser and it was experimentally proved that the width of the softened region in the laser beam weld was less than 1/7 that of a TIG weld. Moreover the hardness in the softened region of the laser beam weld was found to be almost fully recovered to the base metal hardness by applying a post-weld aging treatment at 443 K for 28.8 ks without solution annealing unlike the TIG weld. These results characterize the advantage of laser beam welding in joining of the age-hardenable aluminum alloy as compared with the conventional arc welding. The hardness distributions in the HAZ were theoretically evaluated based on kinetic equations describing the dissolution of hardening β' (Mg2Si) precipitates and the precipitation of non-hardening β' (Mg2Si) precipitates during the weld thermal cycles to quantitatively prove above mentioned advantageous characteristics of laser beam welding.

  1. Aging and Phase Stability of Alloy 22 Welds FY05 SUMMARY REPORT

    SciTech Connect

    Torres, S G; El-Dasher, B; McGregor, M; Etien, R; Edgecumbe, T S; Gdowski, G; Yang, N; Headley, T; Chames, J; Yio, J L; Garcdea, A

    2005-11-23

    Evaluation of the fabrication processes involved in the manufacture of waste containers is important as these processes can have an effect on the metallurgical structure of an alloy. Since material properties such as strength, toughness, aging kinetics and corrosion resistance are all dependent on the microstructure, it is important that prototypes be built and evaluated for processing effects on the performance of the material. Of particular importance are welds, which have an as-cast microstructure with chemical segregation and precipitation of complex phases resulting from the welding process. The work presented in this report focuses on the effects of processes such as solution annealing, stress mitigation, and welding on the kinetics of precipitation and corrosion properties. For a waste package lifetime of thousands of years, it is impossible to test directly in the laboratory the behavior of Alloy 22 under expected repository conditions. The changes that may occur in these materials must be accelerated. For phase-stability studies this is achieved by accelerating the phase transformations by increasing test temperatures above those anticipated in the proposed repository. For these reasons, Alloy 22 characterization specimens are currently being aged at Lawrence Livermore National Laboratory (LLNL) Aging Facilities for times from 1 hour to 20 years at temperatures ranging from 200-750 C. These data as well as the data from specimens aged at 260 C, 343 C, and 427 C for 100,000 hours at Haynes International will be used for performance confirmation.

  2. Effect of Al Addition on ω Precipitation and Age Hardening of Ti-Al-Mo-Fe Alloys

    NASA Astrophysics Data System (ADS)

    Li, Chenglin; Lee, Dong-Geun; Mi, Xujun; Ye, Wenjun; Hui, Songxiao; Lee, Yongtai

    2016-05-01

    The effect of Al addition on ω precipitation and age-hardening behavior of Ti-9.2Mo-2Fe and Ti-2Al-9.2Mo-2Fe alloy during aging treatment was investigated. The results showed that athermal and isothermal ω phase formation in Ti-2Al-9.2Mo-2Fe alloy was suppressed to a certain extent due to Al addition. In addition, a small amount of athermal ω phase was observed in the β matrix with a size of about ~5 nm during water quenching from above the β transus temperature for both alloys. Isothermal ω formation was also found during aging at temperatures ranging from 573 K to 773 K (300 °C to 500 °C) in both alloys, although it had a limited time of stability at 773 K (500 °C). The hardening due to isothermal ω precipitation exhibited no over-aging as long as ω phase existed in both alloys, and ω phase played a more important role in hardening than α phase. And the ω phase in 50 to 100 nm size exhibited the best hardening effect in Ti-9.2Mo-2Fe alloy. Similarly, α phase with 100 to 200 nm in length showed better hardening effects in Ti-2Al-9.2Mo-2Fe alloy. Both the alloys showed stronger age hardening at an intermediate temperature of 673 K (400 °C) and in the first aging stage at a higher temperature of 773 K (500 °C) due to the sufficiently fine size (50 nm), while they exhibited weaker age hardening at a lower temperature of 573 K (300 °C) and long period aging at a higher temperature of 773 K (500 °C) due to incomplete ω formation and/or coarsening of α phase. No over or peak aging stage was found at 573 K and 673 K (300 °C and 400 °C) during the aging for 72 hours, while the peak hardness values of both alloys aged at 773 K (500 °C) were obtained in the first stage of aging. The hardness of the alloys was very sensitive to size and volume fraction of ω phase, which depends on aging temperature, time, and composition of the involved alloys.

  3. Aging and Phase Stability Studies of Alloy 22 FY08 Final Report

    SciTech Connect

    Torres, S G

    2008-04-03

    This report is a compilation of work done over the past ten years in support of phase stability studies of Alloy 22 for the Yucca Mountain Project and contains information previously published, reported, and referenced. Most sections are paraphrased here for the convenience of readers. Evaluation of the fabrication processes involved in the manufacture of waste containers is important as these processes can have an effect on the metallurgical structure of an alloy. Because material properties such as strength, toughness, aging kinetics and corrosion resistance are all dependent on the microstructure, it is important that prototypes be built and evaluated for processing effects on the performance of the material. Of particular importance are welds, which have an as-cast microstructure with chemical segregation and precipitation of complex phases resulting from the welding process. The work summarized in this report contains information on the effects of fabrication processes such as solution annealing, stress mitigation, heat-to-heat variability, and welding on the kinetics of precipitation, mechanical, and corrosion properties. For a waste package lifetime of thousands of years, it is impossible to test directly in the laboratory the behavior of Alloy 22 under expected repository conditions. The changes that may occur in these materials must be accelerated. For phase stability studies, this is achieved by accelerating the phase transformations by increasing test temperatures above those anticipated in the proposed repository. For these reasons, Alloy 22 characterization specimens were aged at Lawrence Livermore National Laboratory (LLNL) Aging Facilities for times from 1 hour up to 8 years at temperatures ranging from 200-750 C. These data as well as the data from specimens aged at 260 C, 343 C, and 427 C for 100,028 hours at Haynes International will be used for performance confirmation and model validation.

  4. Effects of alloying on aging and hardening processes of steel with 20% nickel

    NASA Technical Reports Server (NTRS)

    Bogachev, I. N.; Zvigintsev, N. V.; Maslakova, T. M.

    1981-01-01

    Measurements of hardness, thermal emf, and electrical resistance were used to study the effects of Co, Mo, Ti and Al contents on aging and hardening processes in Fe 20%Ni steel. It is shown that the effects of these alloying elements differ substantially. Anomalies which arise in the temperature dependence of physical properties due to the presence of cobalt and molybdenum are reduced by the inclusion of titanium and aluminum (and vice versa).

  5. Fatigue and Creep Crack Propagation behaviour of Alloy 617 in the Annealed and Aged Conditions

    SciTech Connect

    Julian K. Benz; Richard N. Wright

    2013-10-01

    The crack propagation behaviour of Alloy 617 was studied under various conditions. Elevated temperature fatigue and creep-fatigue crack growth experiments were conducted at 650 and 800 degrees C under constant stress intensity (triangle K) conditions and triangular or trapezoidal waveforms at various frequencies on as-received, aged, and carburized material. Environmental conditions included both laboratory air and characteristic VHTR impure helium. As-received Alloy 617 displayed an increase in the crack growth rate (da/dN) as the frequency was decreased in air which indicated a time-dependent contribution component in fatigue crack propagation. Material aged at 650°C did not display any influence on the fatigue crack growth rates nor the increasing trend of crack growth rate with decreasing frequency even though significant microstructural evolution, including y’ (Ni3Al) after short times, occurred during aging. In contrast, carburized Alloy 617 showed an increase in crack growth rates at all frequencies tested compared to the material in the standard annealed condition. Crack growth studies under quasi-constant K (i.e. creep) conditions were also completed at 650 degrees C and a stress intensity of K = 40 MPa9 (square root)m. The results indicate that crack growth is primarily intergranular and increased creep crack growth rates exist in the impure helium environment when compared to the results in laboratory air. Furthermore, the propagation rates (da/dt) continually increased for the duration of the creep crack growth either due to material aging or evolution of a crack tip creep zone. Finally, fatigue crack propagation tests at 800 degrees C on annealed Alloy 617 indicated that crack propagation rates were higher in air than impure helium at the largest frequencies and lowest stress intensities. The rates in helium, however, eventually surpass the rates in air as the frequency is reduced and the stress intensity is decreased which was not observed at 650

  6. Change in magnetic properties of a cold rolled and thermally aged Fe-Cu alloy

    NASA Astrophysics Data System (ADS)

    Park, D. G.; Ryu, K. S.; Kobayashi, S.; Takahashi, S.; Cheong, Y. M.

    2010-05-01

    The variation in magnetic properties of a Fe-1%Cu model alloy due to a cold rolling and a thermal aging has been evaluated to simulate the radiation damage of reactor pressure vessel of nuclear power plant. The thermal aging was conducted at 500 °C with different aging times in series. The hysteresis loops, magnetic Barkhausen noise (BN) and Vickers microhardness were measured for prestrained, strained, and thermal aged samples. The coercivity increased by a plastic strain and decreased by thermal aging, The BN decreased in the prestrained and strained samples but large changes were observed in the strained sample. These results were interpreted in terms of the domain wall motion signified by a change in the mean free path associated with microinternal stress and copper rich precipitates.

  7. Aging characteristics of the Al-Si-Cu-Mg cast alloy modified with transition metals Zr, V and Ti

    NASA Astrophysics Data System (ADS)

    Czerwinski, F.; Shaha, S. K.; Kasprzak, W.; Friedman, J.; Chen, D. L.

    2016-03-01

    The hypoeutectic Al-7Si-1Cu-0.5Mg base alloy was modified with different contents of Zr, V and Ti. The wedge-shape samples with varying solidification rates during casting were subjected to isochronal aging at temperatures up to 500 °C. Moreover, as-cast and solution treated alloys were subjected to long-term isothermal aging at 150°C. As a reference, the A380 alloy, seen as commercial standard for the automotive application target, was used. The modified alloys exerted different aging characteristics than the A380 grade with higher peak hardness and lower temperature of alloy softening. Besides, the influence of the applied solidification rates on hardness after aging was less pronounced in modified alloys than in the A380 grade. For three combinations of Zr, V and Ti tested with contents of individual elements ranging from 0.14 to 0.47%, no essential differences in aging characteristics were recorded. The results are discussed in terms of the role of chemistry and heat treatment in generating precipitates contributing to the thermal stability of Al based alloys.

  8. The effects of artificial aging on the microstructure and fracture toughness of Al-Cu-Li alloy 2195

    SciTech Connect

    Chen, P.S.; Kuruvilla, A.K.; Malone, T.W.; Stanton, W.P.

    1998-10-01

    Aluminum-lithium alloys have shown promise for aerospace applications, and National Aeronautics and Space Administration (NASA) has selected the aluminum-lithium Alloy 2195 for the main structural alloy of the super light weight tank (SLWT) for the space shuttle. This alloy has significantly higher strength than conventional 2xxx alloys (such as 2219) at both ambient and cryogenic temperatures. If properly processed and heat treated, this alloy can display higher fracture toughness at cryogenic temperature than at ambient temperature. However, the properties of production materials have shown greater variation than those of other established alloys, as is the case with any new alloy that is being transitioned to a demanding application. A multistep heating-rate controlled (MSRC) aging treatment has been developed that can improve the cryogenic fracture toughness of aluminum-lithium Alloy 2195. At the same levels of yield strength (YS), this treatment results in considerably higher fracture toughness than that found in Alloy 2195, which has received conventional (isothermal) aging. Transmission electron microscopy revealed that the new treatment greatly reduces the size and density of subgrain-boundary T{sub 1} precipitates. In addition, it promotes T{sub 1} and {theta}{double_prime} nucleation, resulting in a fine and dense distribution of precipitate particles in the matrix. The MSRC aging treatment consists of (a) aging at 127 C (260 F) for 5 h, (b) heating continuously from 127 C (260 F) to 135 C (275 F) at a rate of 0.556 C/h (1 F/h), (c) holding at 135 C (275 F) for 5 h, (d) heating continuously from 135 to 143 C (275 to 290 F) at a rate of 0.556 C/h (1 F/h), and (e) holding at 143 C (290 F) for 25 h to obtain a near peak-aged condition.

  9. Hydrogen Embrittlement Susceptibility and Hydrogen-Induced Additive Stress of 7050 Aluminum Alloy Under Various Aging States

    NASA Astrophysics Data System (ADS)

    Qi, W. J.; Song, R. G.; Qi, X.; Li, H.; Wang, Z. X.; Wang, C.; Jin, J. R.

    2015-09-01

    Hydrogen embrittlement susceptibility of 7050 aluminum alloy under various aging states has been investigated by means of cathodic hydrogen permeation, slow strain rate test, hydrogen determinator, x-ray diffraction, and scanning electron microscope, and effect of hydrogen on atomic binding force of charged alloy has been calculated by free electron theory in this paper. Simultaneously, hydrogen-induced additive stress (σad) of 7050 aluminum alloy hydrogen charged with different current densities under various aging states have been investigated by flowing stress differential method. The results showed that hydrogen concentration of examined alloy increased with increasing charging time or current density under the same aging state. Hydrogen segregation occurred at grain boundaries which enlarged the crystal lattice constant, meanwhile, it reduced the average bonding energy and interatomic bonding force of the grain boundary atoms, thus resulting in hydrogen embrittlement; moreover, σad of 7050 aluminum alloy increased linearly with increasing hydrogen concentration under the same aging state, i.e., under aged: σad = -1.61 + 9.93 × 105 C H, peak aged: σad = -1.55 + 9.67 × 105 C H, over aged: σad = -0.16 + 9.35 × 105 C H, correspondingly, σad increased the susceptibility to hydrogen embrittlement ( I HE) further. Under the same charging condition, aging states had a great influence on σad and I HE, the under-aged state alloy was of the highest, the over-aged state alloy was of the lowest, and peak-aged was in the middle.

  10. Effect of aging on magnetic properties of Hiperco® 27, Hiperco® 50, and Hiperco 50 HS® alloys

    NASA Astrophysics Data System (ADS)

    Fingers, Richard T.; Carr, Roger P.; Turgut, Zafer

    2002-05-01

    We started a long-term aging study that will identify the aging related changes in magnetic, mechanical, and electrical properties of three Fe-Co soft magnetic alloys. We performed the aging at a temperature of 773 K and in two different environmental chambers, argon gas and air, in order to determine the oxidation resistance of these alloy laminates as well. Each aging batch includes creep and yield stress test specimens, rings for ac magnetic measurements and specimens for electrical resistivity and microstructural analysis. Here we report the change in total power losses after 2000 h annealing up to frequencies of 2 kHz for the Hiperco® 27, Hiperco® 50, and Hiperco® 50 HS alloys. We also report the temperature dependence of total power losses between 298 and 773 K for these alloys.

  11. In vivo aging of orthodontic alloys: implications for corrosion potential, nickel release, and biocompatibility.

    PubMed

    Eliades, Theodore; Athanasiou, Athanasios E

    2002-06-01

    Despite the large number of studies investigating nickel release from orthodontic stainless steel and nickel-titanium alloys, there is a lack of conclusive evidence with respect to the composition and kinetics of the corrosive products released. The objective of this review is to address the critical issues of corrosion potential and nickel leaching from alloys by investigating the effect of intraoral conditions on the surface reactivity of the materials. After an overview of fundamentals of metallurgical structure of orthodontic alloys, we provide an analysis of corrosion processes occurring in vivo. We present recent evidence suggesting the formation of a proteinaceous biofilm on retrieved orthodontic materials that later undergoes calcification. We illustrate the vastly irrelevant surface structure of in vivo- vs in vitro-aged alloys and discuss the potential implications of this pattern in the reactivity of the materials. Finally, we present a comprehensive review of the issue of nickel release, based on three perspectives: its biologic effects, the methods used for studying its release, and nickel-induced hypersensitivity in orthodontic patients. PMID:12071606

  12. Numerical Simulation of Residual Stress in an Al-Cu Alloy Block During Quenching and Aging

    NASA Astrophysics Data System (ADS)

    Dong, Ya-Bo; Shao, Wen-Zhu; Lu, Liang-Xing; Jiang, Jian-Tang; Zhen, Liang

    2015-12-01

    In this study, residual stresses after different quenching and aging processes of Al-Cu forged blocks were investigated by numerical simulation method and experimental measurements. An iterative zone-based heat transfer calculation was coupled with the hyperbolic sine-type constitutive model to simulate the residual stress during quenching process. The simulation results were compared with experiment data using both x-ray diffraction and crack compliance methods. The simulation results were in good agreement with the experimental measurements with around 9-13% deviation at the largest. Residual stress reduction can be achieved by decreasing the cooling rate during quenching. Quenching in water with different temperatures of 60, 80, and 100 °C resulted in the maximum compressive residual stress reduction of approximately 28.2, 75.7, and 88.9%, respectively, in Al-Cu alloy samples. When quenched in 10, 20, and 30% PAG solution, the reduction of maximum compressive residual stress in Al-Cu alloy samples was approximately 35.1, 47.8, and 53.2%, respectively. In addition, in order to study the amount of residual stress relief after aging treatments, aging treatments at 140 and 170 °C for different times were also studied. Aging treatment used to obtain the peak-aged (T6) and overaged (T7) condition produces only about 22.5 to 34.7% reduction in residual stresses.

  13. Aging kinetics of a silicon carbide reinforced Al-Zn-Mg-Cu alloy

    SciTech Connect

    Davies, C.H.J.; Raghunathan, N.; Sheppard, T.

    1994-01-01

    The aging kinetics of a composite of an Al-Zn-Mg-Cu powder (CW67) combined with a varied volume fraction of a particulate silicon carbide were investigated by means of differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM). DSC revealed that the maximum rate of precipitation of the metastable {eta}{prime} phase was substantially lower for CW67/SiC/20p than for the unreinforced alloy or CW67/SiC/10p. TEM of isothermally aged material revealed differences between the unreinforced alloy and composites in respect of precipitate size and morphology. The authors conclude that SiC additions, by dint of additional dislocations generated during quenching, can affect the aging of CW67 either by accelerating the nucleation of precipitates or by accelerating precipitate growth. The aging rate of CW67/SiC/20p was increased by accelerating both the nucleation of precipitates and growth, whereas the aging in CW67/SiC10p was enhanced by accelerating precipitate growth only.

  14. Effect of aging on the fatigue crack growth kinetics of an Al-Zn-Mg-Cu alloy in two directions

    SciTech Connect

    Alpay, S.P.; Guerbuez, R. . Dept. of Metallurgical Engineering)

    1994-02-15

    There have been investigations discussing the effect of aging condition, and thereby the microstructure, on the fatigue crack growth characteristics of precipitation hardening alloys. Lindigkeit et al.., testing an Al-Zn-Mg-Cu alloy of composition corresponding to the commercial alloy 7075 concluded that the crack propagation resistance of underaged microstructures with shearable precipitates is significantly higher than overaged samples of same strength containing non-shearable particles. They reported that this behavior cannot be explained on the basis of slip reversibility alone. A similar conclusion is drawn by Zaiken and Ritchie from investigations on the effect of microstructure on the fatigue crack growth rate of an 7150 aluminum alloy, which is a somewhat high-purity version of the alloy 7050, with lower Fe and Si contents. It is also interesting that aging conditions showing high resistance to fatigue crack growth at low [Delta]K regimes, do not necessarily retain their superiority at medium and high stress intensity ranges.

  15. Aging effects on the fracture toughness of SiC whisker reinforced 2XXX aluminum alloys

    NASA Technical Reports Server (NTRS)

    Ratnaparkhi, P. L.; Rack, H. J.

    1989-01-01

    The effect of aging (at 150 C) time on the fracture toughness behavior of a 2XXX alloy (Al-3.55Cu-1.29Mg-0.01Fe-trace Mn) reinforced with 5 vol pct F-8 SiC whiskers was investigated by measuring hardness and electrical conductivity followed by fracture toughness tests on center-cracked specimens. The ageing time-hardening response plots showed that, independent of whisker orientation, the initial rapid increase in hardness was followed by a more gradual increase, with a broad hardness peak between 32 and 128 hrs of aging. Coincident with the hardness changes, the electrical conductivity initially decreased, reached a minimum, and then increased at aging times beyond 32 hrs. Examination by SEM indicated that the initial increase in hardness and decrease in conductivity was due to the GPB zone formation, while the subsequent increase in electrical conductivity and decrease in hardness (overaging) was due to S nucleation and growth.

  16. CONVERSION OF PLUTONIUM TRIFLUORIDE TO PLUTONIUM TETRAFLUORIDE

    DOEpatents

    Fried, S.; Davidson, N.R.

    1957-09-10

    A large proportion of the trifluoride of plutonium can be converted, in the absence of hydrogen fluoride, to the tetrafiuoride of plutonium. This is done by heating plutonium trifluoride with oxygen at temperatures between 250 and 900 deg C. The trifiuoride of plutonium reacts with oxygen to form plutonium tetrafluoride and plutonium oxide, in a ratio of about 3 to 1. In the presence of moisture, plutonium tetrafluoride tends to hydrolyze at elevated temperatures and therefore it is desirable to have the process take place under anhydrous conditions.

  17. Stability of ultrafine lamellar structures during aging in two-phase {gamma}-TiAl alloys

    SciTech Connect

    Maziasz, P.J.; Liu, C.T.; Wright, J.L.

    1997-08-01

    Two-phase {gamma}-tail alloys such as PM Ti-47Al-2Cr-2Nb or Ti-47Al- 2Cr-1Nb-Ta hot extruded above the {alpha}-transus temperature have unique refined-colony/ultrafine lamellar structures. These lamellar microstructures consist of very fine laths of the {gamma} and {alpha}{sub 2} phases, with average interlamellar spacings of 100 nm and {alpha}{sub 2}-{alpha}{sub 2} spacings of 200 nm, and are dominated by {gamma}/{alpha}{sub 2} interfaces. This ultrafine lamellar structure remains stable during 900 C heat treatment for 2 h, but becomes unstable after 4 h at 982 C. This structure remains stable in both alloys after aging for >5000 h at 800 C but disappears completely at 1000 C. Continuous coarsening begins with dissolution of fine {alpha}{sub 2} lamellea. The aged Ta-modified alloy shows similar lamellar coarsening behavior within the colonies but has more discontinuous coarsening of the intercolony {gamma} with new precipitation of coarse {alpha}{sub 2} and {beta} phase particles. Analytical electron microscopy show that changes in {alpha}{sub 2} phase composition correlate with microstructural instability.

  18. Influence of delay step conditions between quenching and aging on the precipitation mechanisms in the alloy AlZnMg AA7028 aging process

    SciTech Connect

    Calatayud, A.; Ferrer, C.; Amigo, V.; Salvador, M.D.

    1997-03-15

    Among precipitation-hardened alloys, the Al-Zn-Mg system includes the aluminium alloys with higher-strength. The relatively high solubility of Zn and Mg in aluminium makes it possible to produce a high density of precipitates, which results in a higher strength increase. AlZnMg low copper or copper free alloys have the advantage of being easily weldable and, moreover, they harden significantly at room temperature with respect to other weldable aluminium alloys. Due to the remarkable degree of natural aging achieved by AA7000 alloys, the time interval at room temperature between quenching and the beginning of the artificial aging treatment is a variable that must be taken into account. This work was undertaken to evaluate the influence of cooling kinetics at quenching on alloy mechanical characteristics in artificial aging at several temperatures T{sub 2}. The effect of variables that define delays after quenching, basically time t{sub 1} and temperature T{sub 1} was also analyzed. Likewise, this work studies microstructural evolution of material exposed to aging treatments, resulting from the combination of the above mentioned variables.

  19. Age-hardening associated with grain boundary precipitation in a commercial dental gold alloy.

    PubMed

    Kim, H I; Jang, M I; Kim, M S

    1999-03-01

    The aim of this study was to make clear the age-hardening mechanism in a dental high carat gold alloy. For this purpose, age-hardening behaviour of a commercial dental high carat gold alloy, 65.5 wt% Au-14.0 wt% Ag-10.0 wt% Cu-8.9 wt% Pt, was investigated by means of hardness testing, X-ray diffraction study and scanning electron microscopy. Age-hardening was generated by the coherency strain resulting from the transformation of the alpha single phase to the Ag-rich alpha 1 phase and the AuCu I type ordered phase. The coherency strain seemed to be associated with the nucleation of the AuCu ordered structure initially, and then was brought about with the simultaneous formation of the Ag-rich alpha 1 phase and the AuCu I type ordered phase. Hardening was attributed mainly to the very fine coherent precipitates of a lamellar structure composed of the Ag-rich alpha 1 phase and the AuCu I type ordered phase at grain boundaries, and softening, which occurred following prolonged ageing, was due to the coarsening of the fine lamellar structure by releasing the strain at the interfaces of the adjacent lamellae. PMID:10194730

  20. An increase of structural order parameter in Fe-Co-V soft magnetic alloy after thermal aging

    NASA Astrophysics Data System (ADS)

    Zhu, Q.; Li, L.; Masteller, M. S.; Del Corso, G. J.

    1996-12-01

    Alloys of Fe49Co49V2 (Hiperco Alloy 50) (Hiperco is a registered trademark of CRS Holdings, Inc.), both annealed and thermally aged, were studied using anomalous synchrotron x-ray and neutron powder diffraction. Rietveld and diffraction profile analysis indicated both an increase in the structural order parameter and a small lattice expansion (˜0.0004 Å) after aging at 450 °C for 200 h. In addition, a cubic minority phase (<0.3%) was identified in the ``annealed'' sample, which increased noticeably (0.3%→0.8%) as a result of aging. The presence of antiphase domain boundaries in the alloys was also revealed. These results directly correlate with the observed changes in the magnetization behavior and challenge the notion that a ``fully'' ordered Fe-Co alloy demonstrates optimum soft magnetic properties.

  1. Zone refining of plutonium metal

    SciTech Connect

    1997-05-01

    The purpose of this study was to investigate zone refining techniques for the purification of plutonium metal. The redistribution of 10 impurity elements from zone melting was examined. Four tantalum boats were loaded with plutonium impurity alloy, placed in a vacuum furnace, heated to 700{degrees}C, and held at temperature for one hour. Ten passes were made with each boat. Metallographic and chemical analyses performed on the plutonium rods showed that, after 10 passes, moderate movement of certain elements were achieved. Molten zone speeds of 1 or 2 inches per hour had no effect on impurity element movement. Likewise, the application of constant or variable power had no effect on impurity movement. The study implies that development of a zone refining process to purify plutonium is feasible. Development of a process will be hampered by two factors: (1) the effect on impurity element redistribution of the oxide layer formed on the exposed surface of the material is not understood, and (2) the tantalum container material is not inert in the presence of plutonium. Cold boat studies are planned, with higher temperature and vacuum levels, to determine the effect on these factors. 5 refs., 1 tab., 5 figs.

  2. Effects of long-term thermal aging on the tensile and creep properties of commercially heat-treated alloy 718

    SciTech Connect

    Booker, M.K.

    1984-01-01

    Alloy 718 is a structure material widely used in elevated-temperature applications. In particular, it was extensively used in the design of the upper internal system and control rod drive line of the proposed Clinch River Breeder Reactor. Its popularity is due to several excellent behavioral features, including high creep and creep-rupture strength, good oxidation resistance, and exceptional high-cycle fatigue strength. However, alloy 718 is extremely complex, and its microstructure can be significantly modified by thermal treatment. The stability of the alloy in long-term elevated-temperature service is therefore a substantial concern in any such application. This report presents tensile and creep data obtained on three heats of alloy 718 after thermal aging for up to 27,000 h from 593 to 76{degree}C. Implications of these results in terms of long-term stability of the alloy are discussed. 5 refs., 13 figs., 6 tabs.

  3. Plutonium story

    SciTech Connect

    Seaborg, G T

    1981-09-01

    The first nuclear synthesis and identification (i.e., the discovery) of the synthetic transuranium element plutonium (isotope /sup 238/Pu) and the demonstration of its fissionability with slow neutrons (isotope /sup 239/Pu) took place at the University of California, Berkeley, through the use of the 60-inch and 37-inch cyclotrons, in late 1940 and early 1941. This led to the development of industrial scale methods in secret work centered at the University of Chicago's Metallurgical Laboratory and the application of these methods to industrial scale production, at manufacturing plants in Tennessee and Washington, during the World War II years 1942 to 1945. The chemical properties of plutonium, needed to devise the procedures for its industrial scale production, were studied by tracer and ultramicrochemical methods during this period on an extraordinarily urgent basis. This work, and subsequent investigations on a worldwide basis, have made the properties of plutonium very well known. Its well studied electronic structure and chemical properties give it a very interesting position in the actinide series of inner transition elements.

  4. Plutonium Story

    DOE R&D Accomplishments Database

    Seaborg, G. T.

    1981-09-01

    The first nuclear synthesis and identification (i.e., the discovery) of the synthetic transuranium element plutonium (isotope /sup 238/Pu) and the demonstration of its fissionability with slow neutrons (isotope /sup 239/Pu) took place at the University of California, Berkeley, through the use of the 60-inch and 37-inch cyclotrons, in late 1940 and early 1941. This led to the development of industrial scale methods in secret work centered at the University of Chicago's Metallurgical Laboratory and the application of these methods to industrial scale production, at manufacturing plants in Tennessee and Washington, during the World War II years 1942 to 1945. The chemical properties of plutonium, needed to devise the procedures for its industrial scale production, were studied by tracer and ultramicrochemical methods during this period on an extraordinarily urgent basis. This work, and subsequent investigations on a worldwide basis, have made the properties of plutonium very well known. Its well studied electronic structure and chemical properties give it a very interesting position in the actinide series of inner transition elements.

  5. Microstructure evolution in age-hardenable aluminium alloy during processing by hydrostatic extrusion.

    PubMed

    Lewandowska, M

    2006-10-01

    In the present work, scanning and transmission electron microscopy were used to investigate the microstructural evolution occurring during the hydrostatic extrusion of an age-hardenable aluminium alloy. It was shown that processing by hydrostatic extrusion leads to grain refinement to 95 nm in equivalent diameter. Hydrostatic extrusion also influences the geometrical parameters of two different types of particle: intermetallic inclusions and precipitates. The intermetallic inclusions slightly decrease in mean equivalent diameter, but their size remains at the micrometre level. The precipitates are fragmented to nanoscale spherical particles, and their evolution delays the process of grain refinement. PMID:17100901

  6. Probing phonons in plutonium

    SciTech Connect

    Wong, Joe; Krisch, M.; Farber, D.; Occelli, F.; Schwartz, A.; Chiang, T.C.; Wall, M.; Boro, C.; Xu, Ruqing

    2010-11-16

    Plutonium (Pu) is well known to have complex and unique physico-chemical properties. Notably, the pure metal exhibits six solid-state phase transformations with large volume expansions and contractions along the way to the liquid state: {alpha} {yields} {beta} {yields} {gamma} {yields} {delta} {yields} {delta}{prime} {yields} {var_epsilon} {yields} liquid. Unalloyed Pu melts at a relatively low temperature {approx}640 C to yield a higher density liquid than that of the solid from which it melts, (Figure 1). Detailed understanding of the properties of plutonium and plutonium-based alloys is critical for the safe handling, utilization, and long-term storage of these important, but highly toxic materials. However, both technical and and safety issues have made experimental observations extremely difficult. Phonon dispersion curves (PDCs) are key experimenta l data to the understanding of the basic properties of Pu materials such as: force constants, sound velocities, elastic constants, thermodynamics, phase stability, electron-phonon coupling, structural relaxation, etc. However, phonon dispersion curves (PDCs) in plutonium (Pu) and its alloys have defied measurement for the past few decades since the discovery of this element in 1941. This is due to a combination of the high thermal-neutron absorption cross section of plutonium and the inability to grow the large single crystals (with dimensions of a few millimeters) necessary for inelastic neutron scattering. Theoretical simulations of the Pu PDC continue to be hampered by the lack of suitable inter -atomic potentials. Thus, until recently the PDCs for Pu and its alloys have remained unknown experimentally and theoretically. The experimental limitations have recently been overcome by using a tightly focused undulator x-ray micro-beam scattered from single -grain domains in polycrystalline specimens. This experimental approach has been applied successfully to map the complete PDCs of an fcc d-Pu-Ga alloy using the

  7. Structure and properties during aging of an ultra-high strength Al-Cu-Li-Ag-Mg alloy

    NASA Technical Reports Server (NTRS)

    Gayle, Frank W.; Heubaum, Frank H.; Pickens, Joseph R.

    1990-01-01

    The structure and properties of the strengthening phases formed during aging in an Al-Cu-Li-Ag-Mg alloy (Weldalite 049) were elulcidated, by following the development of the microstructure by means of TEM. The results of observations showed that the Weldalite 049 alloy has a series of unusual and technologically useful combinations of mechanical properties in different aging conditions, such as natural aging without prior cold work to produce high strengths, a reversion temper of lower yield strength and unusually high ductility, a room temperature reaging of the reversion temper eventually leading to the original T4 hardness, and ultrahigh-strength T6 properties.

  8. Thermal aging behavior of ERNiCr-3 alloy (weld and base metal)

    SciTech Connect

    Klueh, R.L.; King, J.F.

    1981-08-01

    The nickel-base filler metal alloy ERNiCr-3, containing nominally 67% Ni, 20% Cr, 3% Fe, 3% Mn, and 2.5% Nb, is used widely to make welds for elevated-temperature service. To determine the effect of elevated temperature on tensile and creep-rupture properties of ERNiCr-3, weld metal specimens were thermally aged to 10,000 h at 510/sup 0/C, to 15,000 h at 566/sup 0/C, and to 1000 h at 677/sup 0/C. Wrought ERNiCr-3 was also aged at 566 and 677/sup 0/C. The 0.2% yield strength of the ERNiCr-3 weld metal increased with thermal aging time at 510 and 566/sup 0/C. The ultimate tensile strength also increased continuously with aging time at 566/sup 0/C, whereas at 510/sup 0/C, it went through a maximum (the strength of the material aged 10,000 h was less than was that aged 5000 h).

  9. Effect of Sc on Aging Kinetics in a Direct Chill Cast Al-Zn-Mg-Cu Alloy

    NASA Astrophysics Data System (ADS)

    Senkov, O. N.; Senkova, S. V.; Shagiev, M. R.

    2008-05-01

    The effect of Sc additions on precipitation strengthening in a direct chill (DC) cast Al-Zn-Mg-Cu alloy was studied after natural and artificial aging. The microhardness, room temperature (RT) mechanical properties, and phase composition of the alloys were determined after different steps of aging. The strengthening mechanisms were discussed. It was shown that minor additions of Sc increased the strength of the Al-Zn-Mg-Cu alloy after casting and solution heat treatment, due to the precipitation of fine coherent Al3(Sc,Zr) particles. An analysis of the aging kinetics revealed that Sc had no effect on the natural aging, which was controlled by the formation and growth of Guinier-Preston (GP) I zones. On the other hand, the Sc additions accelerated the aging process at 120 °C and 150 °C within a period of time of the formation and growth of GP II zones and η' particles. It was concluded that the presence of Sc accelerated the formation and growth of GP II zones in the Al-Zn-Mg-Cu alloys, which led to the earlier precipitation of the η' phase. However, at longer aging times at 120 °C and 150 °C, the aging response of the Sc-containing alloys slowed down, due to faster coarsening of the η' particles and their transformation into η particles. A model of the formation of vacancy-rich clusters (VRCs), precursors to GP zones, in the Al-Zn-Mg-based alloys was proposed. According to this model, the observed effects of Sc on aging are the result of the Sc-induced increase in the number density of the GP II clusters and the concentration of quenched-in solute-bound excess vacancies.

  10. Microstructural evolution of Cu-1at% Ti alloy aged in a hydrogen atmosphere and its relation with the electrical conductivity.

    PubMed

    Semboshi, Satoshi; Al-Kassab, Talaat; Gemma, Ryota; Kirchheim, Reiner

    2009-04-01

    Copper alloys with titanium additions between 1 and 6at% Ti emerge currently as attractive conductive materials for electrical and electronic commercial products, since they exhibit superior mechanical and electrical properties. However, their electrical conductivity is reduced owing to the residual amount of Ti solutes in the Cu solid solution (Cu(ss)) phase. Since Cu shows only poor reactivity with hydrogen (H), while Ti exhibits high affinity to it, we were inspired by the idea that hydrogenation of Cu-Ti alloys would influence their microstructure, resulting in a significant change of their properties. In this contribution, the influence of aging under a deuterium (D(2)) atmosphere of Cu-1at% Ti alloys on their microstructure is investigated to explore the effects on the electrical conductivity. The specimens were investigated by means of transmission electron microscopy (TEM), field ion microscopy (FIM), computer-aided field ion image tomography (cFIIT), and atom probe tomography (APT). At an early aging stage at 623K in a D(2) atmosphere of 0.08MPa, ellipsoidal alpha-Cu(4)Ti precipitates are formed in the alloy, and during subsequent aging, delta-TiD(2) is competitively nucleated instead of growth of alpha-Cu(4)Ti particles. The co-precipitation of alpha-Cu(4)Ti and delta-TiD(2) efficiently reduces the Ti concentration of Cu(ss) matrix, particularly in the later aging stages in comparison to the aging in vacuum conditions. The electrical conductivity of the alloy aged in the D(2) atmosphere increases steeply up to 48% International Annealed Copper Standard (IACS) after 1030h, while it saturates to approximately 20% IACS in the alloy aged in vacuum. The outstanding increase of electrical conductivity during aging in D(2) atmosphere can be basically explained by the reduction of Ti solute concentration in Cu(ss) matrix. PMID:19243888

  11. Structure and properties during aging of an Al-Cu-Li-Ag-Mg alloy, Weldalite (tm) 049

    NASA Technical Reports Server (NTRS)

    Gayle, Frank W.; Heubaum, Frank H.; Pickens, Joseph R.

    1991-01-01

    An Al-Cu-Li-Ag-Mg alloy, Weldalite (trademark) 049, was recently introduced as an ultra-high strength alloy (7000 MPa yield strength in artificially aged tempers) with good weldability. In addition, the alloy exhibits an extraordinary natural aging response (440 MPa yield strength (YS) in the unstretch condition) and a high ductility reversion condition which may be useful as a cold-forming temper. In contrast to other Al-Li alloys, these properties can essentially be obtained with or without a stretch or other coldworking operation prior to aging. Preliminary studies have revealed that the T4 temper (no stretch, natural age) is strengthened by a combination of GP zones and delta prime (Al3Li). The T6 temper (no stretch, aged at 180 C to peak strength) was reported to be strengthened primarily by T(sub 1) phase (Al2CuLi) with a minor presence of a theta prime like (Al2Cu) phase. On the other hand, a similar but lower solute containing alloy was reported to contain omega, (stoichiometry unknown), theta prime, and S prime in the peak strength condition. The purpose of this study is to further elucidate the strengthening phases in Weldalite (trademark) 049 in the unstretched tempers, and to follow the development of the microstructure from the T4 temper through reversion (180 C for 5 to 45 minutes) to the T6 temper.

  12. Ti-Mo alloys employed as biomaterials: effects of composition and aging heat treatment on microstructure and mechanical behavior.

    PubMed

    Cardoso, Flavia F; Ferrandini, Peterson L; Lopes, Eder S N; Cremasco, Alessandra; Caram, Rubens

    2014-04-01

    The correlation between the composition, aging heat treatments, microstructural features and mechanical properties of β Ti alloys is of primary significance because it is the foundation for developing and improving new Ti alloys for orthopedic biomaterials. However, in the case of Ti-Mo alloys, this correlation is not fully described in the literature. Therefore, the purpose of this study was to experimentally investigate the effect of composition and aging heat treatments on the microstructure, Vickers hardness and elastic modulus of Ti-Mo alloys. These alloys were solution heat-treated and water-quenched, after which their response to aging heat treatments was investigated. Their microstructure, Vickers hardness and elastic modulus were evaluated, and the results allow us to conclude that stabilization of the β phase is achieved with nearly 10% Mo when a very high cooling rate is applied. Young's modulus was found to be more sensitive to phase variations than hardness. In all of the compositions, the highest hardness values were achieved by aging at 723K, which was attributed to the precipitation of α and ω phases. All of the compositions aged at 573K, 623K and 723K showed overaging within 80h. PMID:24394773

  13. Improved Corrosion Resistance of As-Extruded GZ51K Biomagnesium Alloy with High Mechanical Properties by Aging Treatment

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaobo; Wang, Qian; Ba, Zhixin; Wang, Zhangzhong; Xue, Yajun

    2016-03-01

    Effects of aging treatment on microstructure, mechanical properties, and corrosion behavior of the as-extruded Mg-5Gd-1Zn-0.6Zr (GZ51K, wt.%) alloy were investigated. Microstructure was observed by optical microscopy and scanning electron microscopy, mechanical properties were tested on a tensile test machine and a microhardness tester, and corrosion behavior was evaluated by mass loss and polarization tests. It is found that most of equiaxed α-Mg grains have long-period stacking ordered (LPSO) structure, and some of them have no LPSO structure. Long-elongated grains are formed in the as-extruded alloy due to partial recrystallization and disappear after being aged at 200 and 220 °C. The as-extruded alloy exhibits both high-yield strength and high ductility. The mechanical properties of the alloy are not apparently enhanced, but the corrosion resistance is significantly improved after aging treatment. Moreover, the alloy with LPSO structure presents uniform corrosion mode in simulated body fluid. The GZ51K alloy with high mechanical properties and uniform corrosion behavior is worthy to be further investigated for biomedical applications.

  14. Springback compensation algorithm for tool design in creep age forming of large aluminum alloy plate

    NASA Astrophysics Data System (ADS)

    Xu, Xiaolong; Zhan, Lihua; Huang, Minghui

    2013-12-01

    The creep unified constitutive equations, which was built based on the age forming mechanism of aluminum alloy, was integrated with the commercial finite element analysis software MSC.MARC via the user defined subroutine, CREEP, and the creep age forming process simulations for7055 aluminum alloy plate parts were conducted. Then the springback of the workpiece after forming was calculated by ATOS Professional Software. Based on the combination between simulation results and calculation of springback by ATOS for the formed plate, a new weighted springback compensation algorithm for tool surface modification was developed. The compensate effects between the new algorithm and other overall compensation algorithms on the tool surface are compared. The results show that, the maximal forming error of the workpiece was reduced to below 0.2mm after 5 times compensations with the new weighted algorithm, while error rebound phenomenon occurred and the maximal forming error cannot be reduced to 0.3mm even after 6 times compensations with fixed or variable compensation coefficient, which are based on the overall compensation algorithm.

  15. Application of the diagrams of phase transformations during aging for optimizing the aging conditions for V1469 and 1441 Al-Li alloys

    NASA Astrophysics Data System (ADS)

    Lukina, E. A.; Alekseev, A. A.; Antipov, V. V.; Zaitsev, D. V.; Klochkova, Yu. Yu.

    2009-12-01

    To describe the changes in the phase composition of alloys during aging, it is convenient to construct TTT diagrams on the temperature-aging time coordinates in which time-temperature regions of the existence of nonequilibrium phases that form during aging are indicated. As a rule, in constructing the diagrams of phase transformations during aging (DPTA), time-temperature maps of properties are plotted. A comparison of the diagrams with maps of properties allows one to analyze the effect of the structure on the properties. In this study, we analyze the DPTAs of V1469 (Al-1.2 Li-0.46 Ag-3.4 Cu-0.66 Mg) and 1441 (Al-1.8 Li-1.1 Mg-1.6 Cu, C Mg/ C Cu ≈ 1) alloys. Examples of the application of DPTA for the development of steplike aging conditions are reported.

  16. Plutonium oxide dissolution

    SciTech Connect

    Gray, J.H.

    1992-09-30

    Several processing options for dissolving plutonium oxide (PuO[sub 2]) from high-fired materials have been studied. The scoping studies performed on these options were focused on PuO[sub 2] typically generated by burning plutonium metal and PuO[sub 2] produced during incineration of alpha contaminated waste. At least two processing options remain applicable for dissolving high-fired PuO[sub 2] in canyon dissolvers. The options involve solid solution formation of PuO[sub 2] With uranium oxide (UO[sub 2]) and alloying incinerator ash with aluminum. An oxidative dissolution process involving nitric acid solutions containing a strong oxidizing agent, such as cerium (IV), was neither proven nor rejected. This uncertainty was due to difficulty in regenerating cerium (IV) ions during dissolution. However, recent work on silver-catalyzed dissolution of PuO[sub 2] with persulfate has demonstrated that persulfate ions regenerate silver (II). Use of persulfate to regenerate cerium (IV) or bismuth (V) ions during dissolution of PuO[sub 2] materials may warrant further study.

  17. Plutonium oxide dissolution

    SciTech Connect

    Gray, J.H.

    1992-09-30

    Several processing options for dissolving plutonium oxide (PuO{sub 2}) from high-fired materials have been studied. The scoping studies performed on these options were focused on PuO{sub 2} typically generated by burning plutonium metal and PuO{sub 2} produced during incineration of alpha contaminated waste. At least two processing options remain applicable for dissolving high-fired PuO{sub 2} in canyon dissolvers. The options involve solid solution formation of PuO{sub 2} With uranium oxide (UO{sub 2}) and alloying incinerator ash with aluminum. An oxidative dissolution process involving nitric acid solutions containing a strong oxidizing agent, such as cerium (IV), was neither proven nor rejected. This uncertainty was due to difficulty in regenerating cerium (IV) ions during dissolution. However, recent work on silver-catalyzed dissolution of PuO{sub 2} with persulfate has demonstrated that persulfate ions regenerate silver (II). Use of persulfate to regenerate cerium (IV) or bismuth (V) ions during dissolution of PuO{sub 2} materials may warrant further study.

  18. Effect of a prior stretch on the aging response of an Al-Cu-Li-Ag-Mg-Zr alloy

    NASA Technical Reports Server (NTRS)

    Kumar, K. S.; Brown, S. A.; Pickens, J. R.

    1990-01-01

    The effect of a prior stretching of an aluminum alloy Al-5.3Cu-1.4Li-0.4Ag-0.4Mg-0.17Zr (in wt pct) on the microstructure that develops during aging of this alloy was investigated by comparing TEM and SAD observations and hardness curves with results for the unstretched alloy. The results suggest that stretching introduces a significant number of dislocations which may act as vacanacy sinks by sweeping vacancies away and thereby decreasing the vacancy concentration available for influencing the natural aging response. In the stretched and near-peak aged condition, a fine homogeneous distribution of T1, theta-prime, and S-prime phases were observed in an alpha solid solution matrix. Upon overaging, virtually all of the theta-prime and most of the S-prime phases were found to dissolve, leaving behind a microstructure of T1 precipitates.

  19. Influence of cold rolling degree and ageing treatments on the precipitation hardening of 2024 and 7075 alloys

    NASA Astrophysics Data System (ADS)

    Naimi, A.; Yousfi, H.; Trari, M.

    2013-08-01

    In the present work, the precipitation hardening of 2024 and 7075 aluminum alloys is investigated as a function of cold rolling degree, ageing time and temperature using Vickers microhardness measurements and differential scanning calorimetry (DSC). It is found that a variation in such parameters can improve the hardness and plays an important role in the precipitation hardening process. At specific ageing temperature, the large cold rolled 7075 alloy exhibits two peaks of hardness. Moreover, for both alloys, the increment of hardness during ageing decreases with increasing the cold rolling degree. While in some cases microhardness measurements give impression that the precipitation reaction is slowed down by deformation, DSC analysis indicates that the precipitation is much accelerated since only a slight deformation decreases strongly the temperatures of reactions. However, the degree of cold rolling does not play a crucial role.

  20. Structure of aging Al-Li-Cu-Zr-Sc-Ag alloy after severe plastic deformation and long-term storage

    NASA Astrophysics Data System (ADS)

    Kaigorodova, L. I.; Rasposienko, D. Yu.; Pushin, V. G.; Pilyugin, V. P.; Smirnov, S. V.

    2015-11-01

    Structural and phase transformations in commercial aging aluminum-lithium Al-1.2 Li-3.2 Cu-0.09 Zr-0.11 Sc-0.4 Ag-0.3 Mg alloy have been studied after severe plastic deformation by high-pressure torsion (at a pressure of 4 GPa with 1, 5, and 10 revolutions of the anvil) and natural aging (roomtemperature storage) for 1 week and 2 years. It has been found that, in this case, the process of static recrystallization is achieved in the alloy, the degree of which increases with an increasing degree of deformation and time of storage.

  1. Interactions between creep, fatigue and strain aging in two refractory alloys

    NASA Technical Reports Server (NTRS)

    Sheffler, K. D.

    1972-01-01

    The application of low-amplitude, high-frequency fatigue vibrations during creep testing of two strain-aging refractory alloys (molybdenum-base TZC and tantalum-base T-111) significantly reduced the creep strength of these materials. This strength reduction caused dramatic increases in both the first stage creep strain and the second stage creep rate. The magnitude of the creep rate acceleration varied directly with both frequency and A ratio (ratio of alternating to mean stress), and also varied with temperature, being greatest in the range where the strain-aging phenomenon was most prominent. It was concluded that the creep rate acceleration resulted from a negative strain rate sensitivity which is associated with the strain aging phenomenon in these materials. (A negative rate sensitivity causes flow stress to decrease with increasing strain rate, instead of increasing as in normal materials). By combining two analytical expressions which are normally used to describe creep and strain aging behavior, an expression was developed which correctly described the influence of temperature, frequency, and A ratio on the TZC creep rate acceleration.

  2. Prediction of Failure Due to Thermal Aging, Corrosion and Environmental Fracture in Amorphous and Titanium Alloys

    SciTech Connect

    Farmer, J C

    2003-04-15

    DARPA is exploring a number of advanced materials for military applications, including amorphous metals and titanium-based alloys. Equipment made from these materials can undergo degradation due to thermal aging, uniform corrosion, pitting, crevice corrosion, denting, stress corrosion cracking, corrosion fatigue, hydrogen induced cracking and microbial influenced corrosion. Amorphous alloys have exceptional resistance to corrosion, due in part to the absence of grain boundaries, but can undergo crystallization and other phase instabilities during heating and welding. Titanium alloys are extremely corrosion resistant due to the formation of a tenacious passive film of titanium oxide, but is prone to hydrogen absorption in crevices, and hydrogen induced cracking after hydrogen absorption. Accurate predictions of equipment reliability, necessary for strategic planning, requires integrated models that account for all relevant modes of attack, and that can make probabilistic predictions. Once developed, model parameters must be determined experimentally, and the validity of models must be established through careful laboratory and field tests. Such validation testing requires state-of-the-art surface analytical techniques, as well as electrochemical and fracture mechanics tests. The interaction between those processes that perturb the local environment on a surface and those that alter metallurgical condition must be integrated in predictive models. The material and environment come together to drive various modes of corrosive attack (Figure 1). Models must be supported through comprehensive materials testing capabilities. Such capabilities are available at LLNL and include: the Long Term Corrosion Test Facility (LTCTF) where large numbers of standard samples can be exposed to realistic test media at several temperature levels; a reverse DC machine that can be used to monitor the propagation of stress corrosion cracking (SCC) in situ; and banks of potentiostats with

  3. Thermal aging modeling and validation on the Mo containing Fe-Cr-Ni alloys

    SciTech Connect

    Yang, Ying; Tan, Lizhen; Busby, Jeremy T.

    2015-04-01

    Thermodynamics of intermetallic phases in Fe-rich Fe-Cr-Ni-Mo alloys is critical knowledge to understand thermal aging effect on the phase stability of Mo-containing austenitic steels, which subsequently facilitates alloy design/improvement and degradation mitigation of these materials for reactor applications. Among the intermetallic phases, Chi (χ), Laves, and Sigma (σ) are often of concern because of their tendency to cause embrittlement of the materials. The focus of this study is thermal stability of the Chi and Laves phases as they were less studied compared to the Sigma phase. Coupled with thermodynamic modeling, thermal stability of intermetallic phases in Mo containing Fe-Cr-Ni alloys was investigated at 1000, 850 and 700 C for different annealing times. The morphologies, compositions and crystal structures of the precipitates of the intermetallic phases were carefully examined by scanning electron microscopy, electron probe microanalysis, X-ray diffraction, and transmission electron microscopy. Three key findings resulted from this study. First, the Chi phase is stable at high temperature, and with decreasing temperature it transforms into the Laves phase that is stable at low temperature. Secondly, Cr, Mo, Ni are soluble in both the Chi and Laves phases, with the solubility of Mo playing a major role in the relative stability of the intermetallic phases. Thirdly, in situ transformation from Chi phase to Laves phase was directly observed, which increased the local strain field, generated dislocations in the intermetallic phases, and altered the precipitate phase orientation relationship with the austenitic matrix. The thermodynamic models that were developed and validated were then applied to evaluating the effect of Mo on the thermal stability of intermetallic phases in type 316 and NF709 stainless steels.

  4. Colloid-associated plutonium aged at room temperature: evaluating its transport velocity in saturated coarse-grained granites.

    PubMed

    Xie, Jinchuan; Lin, Jianfeng; Wang, Yu; Li, Mei; Zhang, Jihong; Zhou, Xiaohua; He, Yifeng

    2015-01-01

    The fate and transport of colloidal contaminants in natural media are complicated by physicochemical properties of the contaminants and heterogeneous characteristics of the media. Size and charge exclusion are two key microscopic mechanisms dominating macroscopic transport velocities. Faster velocities of colloid-associated actinides than that of (3)H2O were consistently indicated in many studies. However, dissociation/dissolution of these sorbed actinides (e.g., Pu and Np), caused by their redox reactions on mineral surfaces, possibly occurred under certain chemical conditions. How this dissolution is related to transport velocities remains unanswered. In this study, aging of the colloid-associated Pu (pseudo-colloid) at room temperature and transport through the saturated coarse-grained granites were performed to study whether Pu could exhibit slower velocity than that of (3)H2O (UPu/UT <1). The results show that oxidative dissolution of Pu(IV) associated with the surfaces of colloidal granite particles took place during the aging period. The relative velocity of UPu/UT declined from 1.06 (unaged) to 0.745 (135 d) over time. Size exclusion limited to the uncharged nano-sized particles could not explain such observed UPu/UT <1. Therefore, the decline in UPu/UT was ascribed to the presence of electrostatic attraction between the negatively charged wall of granite pore channels and the Pu(V)O2(+), as evidenced by increasing Pu(V)O2(+) concentrations in the suspensions aged in sealed vessels. As a result of this attraction, Pu(V)O2(+) was excluded from the domain closer to the centerline of pore channels. This reveals that charge exclusion played a more important role in dominating UPu than the size exclusion under the specific conditions, where oxidative dissolution of colloid-associated Pu(IV) was observed in the aged suspensions. PMID:25462640

  5. Colloid-associated plutonium aged at room temperature: evaluating its transport velocity in saturated coarse-grained granites

    NASA Astrophysics Data System (ADS)

    Xie, Jinchuan; Lin, Jianfeng; Wang, Yu; Li, Mei; Zhang, Jihong; Zhou, Xiaohua; He, Yifeng

    2015-01-01

    The fate and transport of colloidal contaminants in natural media are complicated by physicochemical properties of the contaminants and heterogeneous characteristics of the media. Size and charge exclusion are two key microscopic mechanisms dominating macroscopic transport velocities. Faster velocities of colloid-associated actinides than that of 3H2O were consistently indicated in many studies. However, dissociation/dissolution of these sorbed actinides (e.g., Pu and Np), caused by their redox reactions on mineral surfaces, possibly occurred under certain chemical conditions. How this dissolution is related to transport velocities remains unanswered. In this study, aging of the colloid-associated Pu (pseudo-colloid) at room temperature and transport through the saturated coarse-grained granites were performed to study whether Pu could exhibit slower velocity than that of 3H2O (UPu/UT < 1). The results show that oxidative dissolution of Pu(IV) associated with the surfaces of colloidal granite particles took place during the aging period. The relative velocity of UPu/UT declined from 1.06 (unaged) to 0.745 (135 d) over time. Size exclusion limited to the uncharged nano-sized particles could not explain such observed UPu/UT < 1. Therefore, the decline in UPu/UT was ascribed to the presence of electrostatic attraction between the negatively charged wall of granite pore channels and the Pu(V)O2+, as evidenced by increasing Pu(V)O2+ concentrations in the suspensions aged in sealed vessels. As a result of this attraction, Pu(V)O2+ was excluded from the domain closer to the centerline of pore channels. This reveals that charge exclusion played a more important role in dominating UPu than the size exclusion under the specific conditions, where oxidative dissolution of colloid-associated Pu(IV) was observed in the aged suspensions.

  6. SEPARATION OF PLUTONIUM

    DOEpatents

    Maddock, A.G.; Smith, F.

    1959-08-25

    A method is described for separating plutonium from uranium and fission products by treating a nitrate solution of fission products, uranium, and hexavalent plutonium with a relatively water-insoluble fluoride to adsorb fission products on the fluoride, treating the residual solution with a reducing agent for plutonium to reduce its valence to four and less, treating the reduced plutonium solution with a relatively insoluble fluoride to adsorb the plutonium on the fluoride, removing the solution, and subsequently treating the fluoride with its adsorbed plutonium with a concentrated aqueous solution of at least one of a group consisting of aluminum nitrate, ferric nitrate, and manganous nitrate to remove the plutonium from the fluoride.

  7. Thermal stability of the microstructure of an aged Nb-Zr-C alloy

    NASA Technical Reports Server (NTRS)

    Uz, Mehmet; Titran, Robert H.

    1990-01-01

    The effects of thermal aging with and without an applied stress on the microstructure of a Nb-Zr-C alloy containing 0.9 wt percent Zr and 0.06 wt percent C were studied. Chemical analysis, metallographic examination, energy dispersive x-ray spectra of the bulk material, and chemical and x-ray analyses of the phase-extracted residue were used to characterize the microstructure. The samples examined were from a creep strength study involving hot and cold working, and various combinations of exposure to temperatures ranging from 1350 to 1755 K with and without applied load for times as long as 34,000 plus hours. The results showed that the initial microstructure consisted primarily of orthorombic precipitates of Nb sub 2 C which were partially or completely transformed to face-centered cubic carbides of nb and Zr, (Zr, Nb)C, upon prolonged exposure to elevated temperatures. Furthermore, it was found that the microstructure of the alloy is extremely stable owing to the very finely distributed precipitates throughout its matrix and along the grain boundaries. The lattice parameters of the cubic carbides were determed to vary from 0.458 to 0.465 nm as the Zr/Nb ratio varied from 38/62 to 75/25.

  8. Group precipitation and age hardening of nanostructured Fe-based alloys with ultra-high strengths

    PubMed Central

    Jiao, Z. B.; Luan, J. H.; Miller, M. K.; Yu, C. Y.; Liu, C. T.

    2016-01-01

    The precipitation of nanoparticles plays a key role in determining the properties of many structural materials, and the understanding of their formation and stabilization mechanisms has been a long standing interest in the material field. However, the critical issues involving the group precipitation of various nanoparticles and their cooperative hardening mechanism remain elusive in the newly discovered Fe-based alloys with nanostructures. Here we quantitatively elucidate the nucleation mechanism, evolution kinetics and hardening effects of the group-precipitated nanoparticles in the Fe-Cu-Ni-Al-based alloys by atom probe tomography together with both first-principles and thermodynamic calculations. Our results provide the compelling evidence for two interesting but complex group precipitation pathways of nanoparticles, i.e., the Cu-rich and NiAl-based precipitations. The co-existence of the two precipitation pathways plays a key role in age hardening kinetics and ultimately enhances the hardening response, as compared to the single particle type of strengthening, therefore providing an effective new approach for strengthening materials for structural applications. PMID:26892834

  9. Group precipitation and age hardening of nanostructured Fe-based alloys with ultra-high strengths.

    PubMed

    Jiao, Z B; Luan, J H; Miller, M K; Yu, C Y; Liu, C T

    2016-01-01

    The precipitation of nanoparticles plays a key role in determining the properties of many structural materials, and the understanding of their formation and stabilization mechanisms has been a long standing interest in the material field. However, the critical issues involving the group precipitation of various nanoparticles and their cooperative hardening mechanism remain elusive in the newly discovered Fe-based alloys with nanostructures. Here we quantitatively elucidate the nucleation mechanism, evolution kinetics and hardening effects of the group-precipitated nanoparticles in the Fe-Cu-Ni-Al-based alloys by atom probe tomography together with both first-principles and thermodynamic calculations. Our results provide the compelling evidence for two interesting but complex group precipitation pathways of nanoparticles, i.e., the Cu-rich and NiAl-based precipitations. The co-existence of the two precipitation pathways plays a key role in age hardening kinetics and ultimately enhances the hardening response, as compared to the single particle type of strengthening, therefore providing an effective new approach for strengthening materials for structural applications. PMID:26892834

  10. Group precipitation and age hardening of nanostructured Fe-based alloys with ultra-high strengths

    NASA Astrophysics Data System (ADS)

    Jiao, Z. B.; Luan, J. H.; Miller, M. K.; Yu, C. Y.; Liu, C. T.

    2016-02-01

    The precipitation of nanoparticles plays a key role in determining the properties of many structural materials, and the understanding of their formation and stabilization mechanisms has been a long standing interest in the material field. However, the critical issues involving the group precipitation of various nanoparticles and their cooperative hardening mechanism remain elusive in the newly discovered Fe-based alloys with nanostructures. Here we quantitatively elucidate the nucleation mechanism, evolution kinetics and hardening effects of the group-precipitated nanoparticles in the Fe-Cu-Ni-Al-based alloys by atom probe tomography together with both first-principles and thermodynamic calculations. Our results provide the compelling evidence for two interesting but complex group precipitation pathways of nanoparticles, i.e., the Cu-rich and NiAl-based precipitations. The co-existence of the two precipitation pathways plays a key role in age hardening kinetics and ultimately enhances the hardening response, as compared to the single particle type of strengthening, therefore providing an effective new approach for strengthening materials for structural applications.

  11. Group precipitation and age hardening of nanostructured Fe-based alloys with ultra-high strengths

    DOE PAGESBeta

    Jiao, Z. B.; Luan, J. H.; Miller, M. K.; Yu, C. Y.; Liu, C. T.

    2016-02-19

    The precipitation of nanoparticles plays a key role in determining the properties of many structural materials, and the understanding of their formation and stabilization mechanisms has been a long standing interest in the material field. However, the critical issues involving the group precipitation of various nanoparticles and their cooperative hardening mechanism remain elusive in the newly discovered Fe-based alloys with nanostructures. Here we quantitatively elucidate the nucleation mechanism, evolution kinetics and hardening effects of the group-precipitated nanoparticles in the Fe-Cu-Ni-Al-based alloys by atom probe tomography together with both first-principles and thermodynamic calculations. Our results provide the compelling evidence for twomore » interesting but complex group precipitation pathways of nanoparticles, i.e., the Cu-rich and NiAl-based precipitations. Lastly, the co-existence of the two precipitation pathways plays a key role in age hardening kinetics and ultimately enhances the hardening response, as compared to the single particle type of strengthening, therefore providing an effective new approach for strengthening materials for structural applications.« less

  12. Thermal stability of the microstructure of an aged Nb-Zr-C alloy

    NASA Technical Reports Server (NTRS)

    Uz, Mehmet; Titran, Robert H.

    1991-01-01

    The effects of thermal aging with and without an applied stress on the microstructure of a Nb-Zr-C alloy containing 0.9 wt percent Zr and 0.06 percent C were studied. Chemical analysis, metallographic examination, energy dispersive X-ray spectra of the bulk material, and chemical and X-ray analyses of the phase-extracted residue were used to characterize the microstructure. The samples examined were from a creep strength study involving hot and cold working, and various combinations of exposure to temperatures ranging from 1350 to 1755 K with and without applied load times as long as 34,000 plus hours. The results showed that the initial microstructure consisted primarily of orthorombic precipitates of Nb sub C which were partially or completely transformed to face-centered cubic carbides of Nb and Zr, (Zr, Nb)C, upon prolonged exposure to elevated temperatures. Furthermore, it was found that the microstructure of the alloy is extremely stable owing to the very finely distributed precipitates throughout its matrix and along the grain boundaries. The lattice parameters of the cubic carbides were determined to vary from 0.458 to 0.465 nm as the Zr/Nb ratio varied from 38/62 to 75/25.

  13. Investigation of the Dynamic Strain Aging and Mechanical Properties in Alloy-625 with Different Microstructures

    NASA Astrophysics Data System (ADS)

    Chatterjee, Arnomitra; Sharma, Garima; Tewari, R.; Chakravartty, J. K.

    2015-03-01

    Tensile tests were carried out on service exposed Alloy 625 ammonia cracker tube used at heavy water production plant to study the effect of microstructure on the serrated yielding and mechanical properties of the material. Owing to temperature gradient during service exposure, the microstructure was different in top, middle, and bottom sections of the tube. Variation of flow stress, ductility, and average work hardening were monitored with temperature. In the present work, emphasis was given on the study of serrated yielding in the service exposed Alloy 625. Detail investigations were made to study the effect of microstructure on the underlying mechanism of dynamic strain aging of the material. The study revealed that both the normal and the inverse Portevin-Le Chatelier effect (PLC) occured in the material at lower and higher temperature regime, respectively. While the normal PLC dynamics was associated with locking of dislocations by interstitial carbon atoms, the inverse one was accomplished by the dislocation pinning by substitutional Mo atoms. Further analyses identified that the basic deformation mechanism was different in middle and bottom samples as that in the top samples which was reflected in the difference in their respective activation energy and stress drop magnitude.

  14. Mechanical properties and microstructure of 6061 aluminum alloy severely deformed by ARB process and subsequently aged at low temperatures

    NASA Astrophysics Data System (ADS)

    Terada, Daisuke; Kaneda, Yoma; Horita, Zenji; Matsuda, Kenji; Hirosawa, Shoichi; Tsuji, Nobuhiro

    2014-08-01

    In order to clarify the aging behavior in ultrafine grained (UFG) Al alloys, a commercial Al-Mg-Si alloy was severely deformed by accumulative roll-bonding (ARB) process and subsequently aged at 100°C or 170°C. The age-hardening behavior and microstructure change during aging were investigated. At 170 °C, age-hardening was observed in solution treated (ST) specimens, but solution-treated and ARB-processed specimens were not hardened by aging. On the other hand, the hardness of the both ST specimen and ARB-processed specimen increased by aging at 100°C. From TEM observation, it was found that the ARB- processed specimen had an ultrafine lamellar boundary structure and the structure was kept during aging at 170°C and 100°C. In the ST specimen aged at 170°C, fine precipitates were observed within coarse grains. In the specimen ARB-processed and subsequently aged at 170°C, coarser precipitates were observed within ultrafine grains and on grain boundaries. It was considered that the reason why the hardness of the specimens ARB-processed and subsequently aged did not increase was coarsening of precipitates. In the specimens aged at 100°C, obvious precipitates were not observed, but clusters Mg and Si seemed to form during the aging, leading to the increase in the hardness of the specimen. From the results, it was suggested that aging at low temperatures could improve mechanical properties of Al alloys through combining grain refinement and precipitation hardening.

  15. TEM microstructural characterization of melt-spun aged Al-6Si-3Cu-xMg alloys

    SciTech Connect

    Lopez, Ismeli Alfonso . E-mail: post18@jupiter.umich.mx; Zepeda, Cuauhtemoc Maldonado; Gonzalez Reyes, Jose Gonzalo; Flores, Ariosto Medina; Rodriguez, Juan Serrato; Gomez, Luis Bejar

    2007-06-15

    Three Al-6Si-3Cu-xMg alloys (x = 0.59, 3.80 and 6.78 wt.%) were produced using melt-spinning. As-melt-spun ribbons were aged at 150, 180 and 210 deg. C for times between 0.05 and 100 h. Microstructural changes were examined using transmission electron microscopy (TEM) and microhardness was measured. TEM analysis of the as-melt-spun alloys revealed 5 nm nanoparticles and larger particles (50 nm) composed of Al{sub 2}Cu ({theta}) for the 0.59% Mg alloy and Al{sub 5}Cu{sub 2}Mg{sub 8}Si{sub 6} (Q) for 3.80% and 6.78% Mg alloys. Silicon solid solubility was extended to 9.0 at.% and Mg in solid solution reached 6.7 at.%. After aging treatments the 6.78% Mg alloy exhibited the most significant increase in microhardness, reaching 260 kg/mm{sup 2}. TEM analysis of aged specimens also showed {theta} and Q phase (5-20 nm nanoparticles and 35-40 nm particles). The combination of the volume fraction and size of the particles plays an important role in microhardness variation.

  16. The effect of trace additions of Zn on the precipitation behavior of alloy 8090 during artificial aging

    NASA Technical Reports Server (NTRS)

    Kilmer, R. J.; Stoner, G. E.

    1991-01-01

    The effect(s) of trace additions of Zn to the artificial aging behavior of alloy 8090 (Al-Li-Cu-Mg-Zr) was investigated in the approximate composition range 0-1 wt-pct Zn. Trace Zn additions were found to delay aging and under equivalent aging treatments (100 hrs at 160 C) the alloy without Zn and the 1.07 wt-pct Zn alloy developed delta-prime-free zones along subgrain boundaries, while the alloys of 0.21 and 0.58 wt-pct Zn did not. DSC analysis indicated that Zn was being incorporated into the delta-prime, shifting it's exotherm to higher temperatures, while having little if any effect on its associated endotherm making it unlikely that it is an artifact of a solvus shift. In the 8090 + 1.07 wt-pct Zn alloy, coarse precipitates were found to reside on subgrain boundaries and EDS indicated that they were rich in Cu and Zn. It was also noted that in the Zn containing 8090 varients, the S prime precipitates were more coarse in size than the baseline 8090.

  17. STRIPPING PROCESS FOR PLUTONIUM

    DOEpatents

    Kolodney, M.

    1959-10-01

    A method for removing silver, nickel, cadmium, zinc, and indium coatings from plutonium objects while simultaneously rendering the plutonium object passive is described. The coated plutonium object is immersed as the anode in an electrolyte in which the plutonium is passive and the coating metal is not passive, using as a cathode a metal which does not dissolve rapidly in the electrolyte. and passing an electrical current through the electrolyte until the coating metal is removed from the plutonium body.

  18. Effects of age hardening on magnetic and transport properties of Mg-1.3 wt% Ce alloys

    SciTech Connect

    Yamashita, T.; Cavallaro, P.; Kelly, P.M.; Hisa, M.

    1998-05-22

    Magnesium is the lightest structural metal. It has advantages over many other materials in terms of specific strength, machinability and shock absorption. Improvements in magnesium alloy design and more stringent requirements to reduce fuel consumption and air pollution, have recently focused attention on the use of magnesium alloys for automotive components. Here, a Mg-1.3 wt% Ce alloy has been isothermally heat treated at 423 K and the transport and magnetic properties are investigated. This alloy is known to have distinct age hardening behavior and its age hardened microstructure has been studied in detail. The transport properties depend on the early stage of precipitation which is difficult to define by transmission electron microscopy. The scattering sites of electrons are not identical to precipitates, but consist of strain fields induced by the precipitates, solute atoms, dislocations and vacancies. The resistivity was found to increase initially with aging time and then decrease. The highest resistivity was obtained from a specimen aged for 3.6 ks. This aging time is far less than that of 1,800 ks which gives the maximum hardness. On the other hand, magnetic properties correlate with the later stages of the precipitation. In particular, the imaginary part of the magnetic susceptibility is related to macroscopic formation of precipitates. The imaginary part of the magnetic susceptibility of the alloys seems to be generated by eddy current loss. The imaginary part of the magnetic susceptibility increases monotonically with aging time but it may decrease for extensive aging treatments beyond 3,600 ks.

  19. Comparative study of structure formation and mechanical behavior of age-hardened Ti–Nb–Zr and Ti–Nb–Ta shape memory alloys

    SciTech Connect

    Inaekyan, K.; Brailovski, V.; Prokoshkin, S.; Pushin, V.; Dubinskiy, S.; Sheremetyev, V.

    2015-05-15

    This work sets out to study the peculiar effects of aging treatment on the structure and mechanical behavior of cold-rolled and annealed biomedical Ti–21.8Nb–6.0Zr (TNZ) and Ti–19.7Nb–5.8Ta (TNT) (at.%) shape memory alloys by means of transmission electron microscopy, X-ray diffractometry, functional fatigue and thermomechanical testing techniques. Dissimilar effects of aging treatment on the mechanical behavior of Zr- and Ta-doped alloys are explained by the differences in the ω-phase formation rate, precipitate size, fraction and distribution, and by their effect on the alloys' critical stresses and transformation temperatures. Even short-time aging of the TNZ alloy leads to its drastic embrittlement caused by “overaging”. On the contrary, during aging of the TNT alloy, formation of finely dispersed ω-phase precipitates is gradual and controllable, which makes it possible to finely adjust the TNT alloy functional properties using precipitation hardening mechanisms. To create in this alloy nanosubgrained dislocation substructure containing highly-dispersed coherent nanosized ω-phase precipitates, the following optimum thermomechanical treatment is recommended: cold rolling (true strain 0.37), followed by post-deformation annealing (600 °C, 15–30 min) and age-hardening (300 °C, 30 min) thermal treatments. It is shown that in TNT alloy, pre-transition diffraction effects (diffuse reflections) can “mask” the β-phase substructure and morphology of secondary phases. - Highlights: • TNZ alloy is characterized by much higher ω-phase precipitation rate than TNT alloy. • Difference in precipitation rates is linked to the difference in Zr and Ta diffusion mobility. • Aging of nanosubgrained TNZ alloy worsens its properties irrespective of the aging time. • Aging time of nanosubgrained TNT alloy can be optimized to improve its properties.

  20. Plutonium Uptake and Distribution in Mammalian Cells: Molecular vs Polymeric Plutonium

    PubMed Central

    ARYAL, BAIKUNTHA P.; GORMAN-LEWIS, DREW; PAUNESKU, TATJANA; WILSON, RICHARD E.; LAI, BARRY; VOGT, STEFAN; WOLOSCHAK, GAYLE E.; JENSEN, MARK P.

    2013-01-01

    Purpose To study the cellular responses to molecular and polymeric forms of plutonium using PC12 cells derived from rat adrenal glands. Materials and methods Serum starved PC12 cells were exposed to polymeric and molecular forms of plutonium for three hours. Cells were washed with 10 mM EGTA, 100 mM NaCl at pH 7.4 to remove surface sorbed plutonium. Localization of plutonium in individual cell was quantitatively analyzed by synchrotron X-ray fluorescence (XRF) microscopy. Results Molecular plutonium complexes introduced to cell growth media in the form of NTA, citrate, or transferrin complexes were taken up by PC12 cells, and mostly co-localized with iron within the cells. Polymeric plutonium prepared separately was not internalized by PC12 cells but it was always found on the cell surface as big agglomerates; however polymeric plutonium formed in situ was mostly found within the cells as agglomerates. Conclusions PC12 cells can differentiate molecular and polymeric forms of plutonium. Molecular plutonium is taken up by PC12 cells and mostly co-localized with iron but aged polymeric plutonium is not internalized by the cells. PMID:21770702

  1. Low strain creep and aging of aluminum alloy 2219-T87 sheet

    NASA Technical Reports Server (NTRS)

    Navrotski, G.; Rummler, D. R.

    1981-01-01

    The constant load creep and isothermal aging characteristics of aluminum alloy 2219-T87 sheet have been studied experimentally and analytically in the temperature range 250 to 650 F at stress levels between 2.9 and 4.0 ksi (20 to 283 MPa). Testing variables were closely and automatically monitored. The data generated agree somewhat with the literature data base at lower temperatures, but above 500 F, discrepancies of greater than an order of magnitude in the time to 1% creep strain occur. Good correlation was found with the Larson-Miller parameter as modeled by a second-order polynomial in stress. Constitutive equations for time to 0.1%, 0.2%, 0.5%, and 1.0% creep are given. Information on residual mechanical properties and electrical conductivity is also provided.

  2. Quantitative evaluation of precipitates in an Al-Zn-Mg-Cu alloy after isothermal aging

    SciTech Connect

    Du, Z.W. . E-mail: zhiweidu110@sohu.com; Sun, Z.M.; Shao, B.L.; Zhou, T.T.; Chen, C.Q.

    2006-03-15

    The evolution of microstructure parameters (precipitate size and volume fraction) for an Al-8.0 Zn-2.05 Mg-1.76 Cu alloy during isothermal ageing has been studied by synchrotron-radiation small angle X-ray scattering (SAXS) combining transmission electron microscopy (TEM). The results show that the precipitates are only a few nanometers even at higher temperature 160 deg. C up to 72 h (5.82 nm). The precipitate volume fraction reaches a plateau except ageing at 120 deg. C and the maximum is about 0.052-0.054 in the range 140-160 deg. C. Models describing the evolution of these two parameters with ageing temperature and time have been constructed for our further predicting the precipitate hardening. The coarsening of precipitate is consistent with LSW (Lifshitz-Slyozov-Wagner) model even in the initial stage where volume fraction is still varying. The activation energy of coarsening regime has been determined to be about 1.25 {+-} 0.02 eV.

  3. Phase decomposition in an Fe-40 at.% Cr alloy after isothermal aging and its effect on hardening

    SciTech Connect

    Lopez-Hirata, Victor M. Soriano-Vargas, Orlando; Rosales-Dorantes, Hector J.; Saucedo Munoz, Maribel L.

    2011-08-15

    The phase decomposition process of an Fe-40 at.% Cr alloy was studied after isothermal aging at 475 and 500 deg. C using a high-resolution transmission electron microscope, as well as hardness measurements. High-resolution transmission electron microscope observations showed that the hardening behavior is associated with the formation of the nanometric coherent decomposed Cr-rich and Fe-rich phases with irregular shape and interconnected as expected for a spinodally-decomposed alloy. As the aging progressed, coherent rounded Cr-rich phase precipitates were observed in the Fe-rich phase matrix. The coarsening process of the Cr-rich phase was observed for aging times up to 750 h. Nevertheless, no decrease in hardness with time was observed because of the nanometric size of the Cr-rich phase, less than 10 nm. Aging hardening was higher at 500 deg. C because of the higher decomposition kinetics. - Research Highlights: {yields} Spinodally-decomposed phases showed an interconnected and irregular shape in aged Fe-Cr alloy. {yields} Further aging promoted the formation of nanometric coherent rounded Cr-rich precipitates. {yields} Nanometric Cr-rich phases are responsible for the age hardening. {yields} Coarsening process of these nanometric Cr-rich precipitates caused no decrease in hardness.

  4. Effects of Aging Treatments on the Mechanical Behavior of Ti-15V-3Cr-3Sn-3Al Alloy

    NASA Astrophysics Data System (ADS)

    Chou, Y.-K.; Tsay, L. W.; Chen, C.

    2015-09-01

    The effect of aging treatments on the mechanical properties and microstructures of Ti-15V-3Cr-3Sn-3Al (Ti-15-3) alloy was evaluated using tensile, notched tensile, and J-integral tests. The properties for the one-step aged specimens (371 to 648 °C for 8 h) were compared with those for the two-step aged specimens (one-step aged + 426 °C/24 h). An increase in aging temperature of one-step aging resulted in increased notched tensile strength and fracture toughness of the Ti-15-3 alloy. The second-step aging at 426 °C for 24 h caused various degrees of hardening in the group of double aged specimens. Comparing to the one-step aged specimens, increased notch brittleness and decreased fracture toughness were observed in the two-step aged specimens. For the specimens subjected to aging at 648 °C, the formation of thick α layer at β grain boundaries resulted in lower tensile properties and fracture toughness. The fracture modes of the notch-brittle specimens were strongly affected by the distribution, size, and morphology of the α precipitates.

  5. The effects of artificial aging on the microstructure and fracture toughness of Al-Cu-Li alloy 2195

    NASA Astrophysics Data System (ADS)

    Chen, P. S.; Kuruvilla, A. K.; Malone, T. W.; Stanton, W. P.

    1998-10-01

    Aluminum-lithium alloys have shown promise for aerospace applications, and National Aeronautics and Space Administration (NASA) has selected the aluminum-lithium Alloy 2195 for the main structural alloy of the super light weight tank (SLWT) for the space shuttle. This alloy has significantly higher strength than conventional 2xxx alloys (such as 2219) at both ambient and cryogenic temperatures. If properly processed and heat treated, this alloy can display higher fracture toughness at cryogenic temperature than at ambient temperature. However, the properties of production materials have shown greater variation than those of other established alloys, as is the case with any new alloy that is being transitioned to a demanding application. Recently, some commercial 2195 plates for the SLWT program were rejected, mostly due to low CFT or FTR at ambient and cryogenic temperatures. Investigation of the microstructure property relationships of Al-Cu-Li based alloys indicates that the poor fracture toughness properties can be attributed to excessive T1 precipitation at subgrain boundaries. Lowering the aging temperature is one way to avoid excessive T1 precipitation at subgrain boundaries. However, this approach results in a significant drop in yield strength. In addition, low-temperature aging is associated with sluggish aging kinetics, which are not desirable for industrial mass production. Therefore, the present study was undertaken to develop an aging process that can improve fracture toughness without sacrificing yield and tensile strength. A multistep heating-rate controlled (MSRC) aging treatment has been developed that can improve the cryogenic fracture toughness of aluminum-lithium Alloy 2195. At the same levels of yield strength (YS), this treatment results in considerably higher fracture toughness than that found in Alloy 2195, which has received conventional (isothermal) aging. Transmission electron microscopy revealed that the new treatment greatly reduces the

  6. Analysis of Magnetic Minor Hysteresis Loops in Thermally Aged and Cold-rolled Fe-Cu Alloys

    NASA Astrophysics Data System (ADS)

    Takahashi, F.; Kobayashi, S.; Murakami, T.; Takahashi, S.; Kamada, Y.; Kikuchi, H.

    2011-01-01

    Neutron irradiation causes the formation of Cu precipitate in reactor pressure vessel steel and makes the steel susceptible to rupture. In the present study, we have examined magnetic minor hysteresis loops of Fe-1wt%Cu alloy after thermally ageing at 753 K and subsequent cold rolling to elucidate the effects of Cu precipitation on magnetic properties. Minor-loop coefficients, obtained from scaling power laws between field-dependent parameters of minor hysteresis loops, decrease with ageing time and show a local maximum around 200 min, reflecting the growth of Cu precipitates with ageing. For the alloy cold-rolled after ageing, the minor-loop properties linearly increase with reduction and show a good relationship with mechanical properties such as DBTT and hardness. These observations indicate that the analysis method using magnetic minor loops can be an useful technique of nondestructive evaluation of irradiation embrittlement and subsequent deformation hardening in reactor pressure vessel steels.

  7. High-Precision Plutonium Isotopic Compositions Measured on Los Alamos National Laboratory’s General’s Tanks Samples: Bearing on Model Ages, Reactor Modelling, and Sources of Material. Further Discussion of Chronometry

    SciTech Connect

    Spencer, Khalil J.; Rim, Jung Ho; Porterfield, Donivan R.; Roback, Robert Clifford; Boukhalfa, Hakim; Stanley, Floyd E.

    2015-06-29

    In this study, we re-analyzed late-1940’s, Manhattan Project era Plutonium-rich sludge samples recovered from the ''General’s Tanks'' located within the nation’s oldest Plutonium processing facility, Technical Area 21. These samples were initially characterized by lower accuracy, and lower precision mass spectrometric techniques. We report here information that was previously not discernable: the two tanks contain isotopically distinct Pu not only for the major (i.e., 240Pu, 239Pu) but trace (238Pu ,241Pu, 242Pu) isotopes. Revised isotopics slightly changed the calculated 241Am-241Pu model ages and interpretations.

  8. PLUTONIUM METALLIC FUELS FOR FAST REACTORS

    SciTech Connect

    STAN, MARIUS; HECKER, SIEGFRIED S.

    2007-02-07

    Early interest in metallic plutonium fuels for fast reactors led to much research on plutonium alloy systems including binary solid solutions with the addition of aluminum, gallium, or zirconium and low-melting eutectic alloys with iron and nickel or cobalt. There was also interest in ternaries of these elements with plutonium and cerium. The solid solution and eutectic alloys have most unusual properties, including negative thermal expansion in some solid-solution alloys and the highest viscosity known for liquid metals in the Pu-Fe system. Although metallic fuels have many potential advantages over ceramic fuels, the early attempts were unsuccessful because these fuels suffered from high swelling rates during burn up and high smearing densities. The liquid metal fuels experienced excessive corrosion. Subsequent work on higher-melting U-PuZr metallic fuels was much more promising. In light of the recent rebirth of interest in fast reactors, we review some of the key properties of the early fuels and discuss the challenges presented by the ternary alloys.

  9. Correlation of Fe/Cr phase decomposition process and age-hardening in Fe-15Cr ferritic alloys

    NASA Astrophysics Data System (ADS)

    Chen, Dongsheng; Kimura, Akihiko; Han, Wentuo

    2014-12-01

    The effects of thermal aging on the microstructure and mechanical properties of Fe-15Cr ferritic model alloys were investigated by TEM examinations, micro-hardness measurements and tensile tests. The materials used in this work were Fe-15Cr, Fe-15Cr-C and Fe-15Cr-X alloys, where X refers to Si, Mn and Ni to simulate a pressure vessel steel. Specimens were isothermally aged at 475 °C up to 5000 h. Thermal aging causes a significant increase in the hardness and strength. An almost twice larger hardening is required for embrittlement of Fe-15Cr-X relative to Fe-15Cr. The age-hardening is mainly due to the formation of Cr-rich α‧ precipitates, while the addition of minor elements has a small effect on the saturation level of age-hardening. The correlation of phase decomposition process and age-hardening in Fe-15Cr alloy was interpreted by dispersion strengthened models.

  10. Thermomechanical deformation behavior of a dynamic strain aging alloy, Hastelloy X

    NASA Technical Reports Server (NTRS)

    Castelli, Michael G.; Miner, Robert V.; Robinson, David N.

    1992-01-01

    An experimental study was performed to identify the effects of dynamic strain aging (solute drag) and metallurgical instabilities under thermomechanical loading conditions. The study involved a series of closely controlled thermomechanical deformation tests on the solid-solution-strenghened nickel-base superalloy, Hastelloy X. This alloy exhibits a strong isothermal strain aging peak at approximately 600 C, promoted by the effects of solute drag and precipitation hardening. Macroscopic thermomechanical hardening trends are correlated with microstructural characteristics through the use of transmission electron microscopy. These observations are compared and contrasted with isothermal conditions. Thermomechanical behavior unique to the isothermal database is identified and discussed. The microstructural characteristics were shown to be dominated by effects associated with the highest temperature of the thermomechanical cycle. Results indicate that the deformation behavior of Hastelloy X is thermomechanically path dependent. In addition, guidance is given pertaining to deformation modeling in the context of macroscopic unified theory. An internal state variable is formulated to qualitatively reflect the isotropic hardening trends identified in the TMD experiments.

  11. Kinetics of Static Strain Aging in Polycrystalline NiAl-based Alloys

    NASA Technical Reports Server (NTRS)

    Weaver, M. L.; Kaufman, M. J.; Noebe, R. D.

    1996-01-01

    The kinetics of yield point return have been studied in two NiAl-based alloys as a function of aging time at temperatures between 300 and 700 K. The results indicate that the upper yield stress increment, Delta sigma(sub u) (i.e., stress difference between the upper yield point and the final flow stress achieved during prestraining), in conventional purity (CP-NiAl) and in high purity carbon-doped (NiAl-C) material first increased with a t(exp 2/3) relationship before reaching a plateau. This behavior suggests that a Cottrell locking mechanism is the cause for yield points in NiAl. In addition, positive y-axis intercepts were observed in plots of Delta sigma(sub u) versus t(exp 2/3) suggesting the operation of a Snoek mechanism. Analysis according to the Cottrell Bilby model of atmosphere formation around dislocations yields an activation energy for yield point return in the range 70 to 76 kJ/mol which is comparable to the activation energy for diffusion of interstitial impurities in bcc metals. It is, thus, concluded that the kinetics of static strain aging in NiAl are controlled by the locking of dislocations by Cottrell atmospheres of carbon atoms around dislocations.

  12. Fundamental Effects of Aging on Creep Properties of Solution-Treated Low-Carbon N-155 Alloy

    NASA Technical Reports Server (NTRS)

    Frey, D N; Freeman, J W; White, A E

    1950-01-01

    A method is developed whereby the fundamental mechanisms are investigated by which processing, heat treatment, and chemical composition control the properties of alloys at high temperatures. The method used metallographic examination -- both optical and electronic --studies of x-ray diffraction-line widths, intensities, and lattice parameters, and hardness surveys to evaluate fundamental structural conditions. Mechanical properties at high temperatures are then measured and correlated with these measured structural conditions. In accordance with this method, a study was made of the fundamental mechanism by which aging controlled the short-time creep and rupture properties of solution-treated low-carbon n-155 alloy at 1200 degrees F.

  13. An increase of structural order parameter in Fe{endash}Co{endash}V soft magnetic alloy after thermal aging

    SciTech Connect

    Zhu, Q.; Li, L.; Masteller, M.S.; Del Corso, G.J.

    1996-12-01

    Alloys of Fe{sub 49}Co{sub 49}V{sub 2} (Hiperco Alloy 50) (Hiperco is a registered trademark of CRS Holdings, Inc.), both annealed and thermally aged, were studied using anomalous synchrotron x-ray and neutron powder diffraction. Rietveld and diffraction profile analysis indicated both an {ital increase} in the structural order parameter and a small lattice {ital expansion} ({approximately}0.0004 A) after aging at 450{degree}C for 200 h. In addition, a cubic minority phase ({lt}0.3{percent}) was identified in the {open_quote}{open_quote}annealed{close_quote}{close_quote} sample, which increased noticeably (0.3{percent}{r_arrow}0.8{percent}) as a result of aging. The presence of antiphase domain boundaries in the alloys was also revealed. These results directly correlate with the observed changes in the magnetization behavior and challenge the notion that a {open_quote}{open_quote}fully{close_quote}{close_quote} ordered Fe{endash}Co alloy demonstrates optimum soft magnetic properties. {copyright} {ital 1996 American Institute of Physics.}

  14. Effects of high temperature aging in an impure helium environment on low temperature embrittlement of Alloy 617 and Haynes 230

    NASA Astrophysics Data System (ADS)

    Kim, Daejong; Sah, Injin; Jang, Changheui

    2010-10-01

    The effects of high temperature environmental damage on low temperature embrittlement of wrought nickel-base superalloys, Alloy 617 and Haynes 230 were evaluated. They were aged in an impure helium environment at 1000 °C for up to 500 h before tensile tested at room temperature. The tensile test results showed that the loss of ductility was associated with the increase in the inter-granular fracture with aging time. For Alloy 617, inter-granular oxidation and coarsening of grain boundary carbides contributed to the embrittlement. The significant loss of ductility in Haynes 230 was only observed after 500 h of aging when the globular intermetallic precipitates were extensively formed and brittle inter-granular cracking began to occur.

  15. Age-hardening behaviors and grain boundary discontinuous precipitation in a Pd-free gold alloy for porcelain bonding.

    PubMed

    Shiraishi, Takanobu; Ohta, Michio

    2002-10-01

    Isothermal age-hardening behaviors at 400 degrees and 450 degrees C and discontinuous precipitation reaction at 450 degrees C in a commercial Pd-free gold alloy for porcelain bonding were investigated by hardness testing, X-ray powder diffraction, and light microscopy. Variations of electrical resistivity during continuous heating and cooling processes were also measured. The alloy exhibited pronounced age-hardening in the early stage of aging and the maximum hardness exceeded twice that of the solution-treated sample. Precise lattice parameter measurements and investigations of full width at half maximum values for the X-ray Bragg reflections implied that nonuniform strains due to the pre-precipitation or zone formation was responsible for the quick and pronounced age-hardening at 450 degrees C. Discontinuous precipitation reaction, producing a mixture of a small amount of Pt(3)In-phase with the L1(2)-type superstructure and a large amount of (Pt, In)-depleted solid solution, started at grain boundaries in the late stage of aging process at 450 degrees C. The growth of the grain boundary discontinuous precipitates toward the intragrain area led to a gradual decrease in hardness of the alloy. PMID:15348193

  16. Over-aging of aluminum alloys. Final report. [7050-T736; 7075-T6; 9021-T4; 9052-F

    SciTech Connect

    Ulitchny, M.G.

    1983-12-01

    The effects of short-time over-aging on the mechanical properties of aluminum alloys 7050-T736, 7075-T6, 9021-T4, and 9052-F have been evaluated. Test results show that when subjected to a temperature of 600/sup 0/F for short periods of time, the 7XXX series alloys lose almost all of the tensile strength they received through heat treatment; alloy 9021-T4 loses less of its strength; and 9052-F loses almost none of its strength. Tensile tests carried out on 7050-T736 and 7075-T6 in both the as-received and stress-relief-annealed conditions have confirmed that the stress relief anneal has little or no effect on tensile strength.

  17. Monetary alloys in Iron Age Armorica (Finistère, France): The singular case of the Osismi tribe

    NASA Astrophysics Data System (ADS)

    Guerra, M. F.; Abollivier, Ph.

    2016-06-01

    The analysis by PIXE and PAA of 64 coins struck in Iron Age Armorica by the Osismi tribe revealed the use of a different system from the usual Celtic Gaul tri-metallic system. The gold-based alloy (Au-Ag-Cu) firstly issued is debased over time to become a silver-based alloy (Ag-Cu-Sn). Based on the analytical data, two chronological phases were defined and dates of issuing could be ascribed to the coin-types. The presence of Sn and Sb in the alloys and the low contents of Pb were used in the attribution of 9 specimens of unknown origin to the Osismi monetary system. Considerations on the mints supplies could also be provided.

  18. Plutonium Immobilization Puck Handling

    SciTech Connect

    Kriikku, E.

    1999-01-26

    The Plutonium Immobilization Project (PIP) will immobilize excess plutonium and store the plutonium in a high level waste radiation field. To accomplish these goals, the PIP will process various forms of plutonium into plutonium oxide, mix the oxide powder with ceramic precursors, press the mixture into pucks, sinter the pucks into a ceramic puck, load the pucks into metal cans, seal the cans, load the cans into magazines, and load the magazines into a Defense Waste Processing Facility (DPWF) canister. These canisters will be sent to the DWPF, an existing Savannah River Site (SRS) facility, where molten high level waste glass will be poured into the canisters encapsulating the ceramic pucks. Due to the plutonium radiation, remote equipment will perform these operations in a contained environment. The Plutonium Immobilization Project is in the early design stages and the facility will begin operation in 2005. This paper will discuss the Plutonium Immobilization puck handling conceptual design and the puck handling equipment testing.

  19. METHOD OF SEPARATING PLUTONIUM

    DOEpatents

    Brown, H.S.; Hill, O.F.

    1958-02-01

    Plutonium hexafluoride is a satisfactory fluorinating agent and may be reacted with various materials capable of forming fluorides, such as copper, iron, zinc, etc., with consequent formation of the metal fluoride and reduction of the plutonium to the form of a lower fluoride. In accordance with the present invention, it has been found that the reactivity of plutonium hexafluoride with other fluoridizable materials is so great that the process may be used as a method of separating plutonium from mixures containing plutonium hexafluoride and other vaporized fluorides even though the plutonium is present in but minute quantities. This process may be carried out by treating a mixture of fluoride vapors comprising plutonium hexafluoride and fluoride of uranium to selectively reduce the plutonium hexafluoride and convert it to a less volatile fluoride, and then recovering said less volatile fluoride from the vapor by condensation.

  20. PREPARATION OF PLUTONIUM TRIFLUORIDE

    DOEpatents

    Burger, L.L.; Roake, W.E.

    1961-07-11

    A process of producing plutonium trifluoride by reacting dry plutonium(IV) oxalate with chlorofluorinated methane or ethane at 400 to 450 deg C and cooling the product in the absence of oxygen is described.

  1. PROCESS FOR PURIFYING PLUTONIUM

    DOEpatents

    Mastick, D.F.; Wigner, E.P.

    1958-05-01

    A method is described of separating plutonium from small amounts of uranium and other contaminants. An acidic aqueous solution of higher valent plutonium and hexavalent uranium is treated with a soluble iodide to obtain the plutonium in the plus three oxidation state while leaving the uranium in the hexavalent state, adding a soluble oxalate such as oxalic acid, and then separating the insoluble plus the plutonium trioxalate from the solution.

  2. The chemistry of precipitates in an aged Al-2.1Zn-1.7Mg at.% alloy

    SciTech Connect

    Maloney, S.K.; Hono, K.; Polmear, I.J.; Ringer, S.P.

    1999-10-22

    Ageing processes in most aluminum alloys are complex and the decomposition of saturated solid solutions obtained by quenching takes place in several stages. Precipitation in Al-Zn-Mg alloys has also been widely considered to involve three stages, the nature of which depends on the alloy composition and in turn the Zn:Mg ratio. For higher ratios, G.P. zones (rich in Zn and Mg) are thought to be replaced gradually by the formation of the intermediate precipitate {eta}{prime} (commonly accepted to have the composition MgZn{sub 2}) and the equilibrium phase {eta} (MgZn{sub 2}), both of which are hexagonal although the lattice parameters are different. For alloys with lower Zn:Mg ratios, the intermediate precipitate may be the cubic T{prime} phase (probably Mg{sub 32}(Al,Zn){sub 49}) and the equilibrium phase T, of the same composition, which is also cubic. The present work uses a combination of transmission electron microscopy (TEM) and three-dimensional atom probe (3DAP) in an attempt to examine the precise compositions of precipitates in a high-purity, ternary Al-Zn-Mg alloy.

  3. PLUTONIUM CLEANING PROCESS

    DOEpatents

    Kolodney, M.

    1959-12-01

    A method is described for rapidly removing iron, nickel, and zinc coatings from plutonium objects while simultaneously rendering the plutonium object passive. The method consists of immersing the coated plutonium object in an aqueous acid solution containing a substantial concentration of nitrate ions, such as fuming nitric acid.

  4. Plutonium immobilization -- Can loading

    SciTech Connect

    Kriikku, E.

    2000-02-17

    The Savannah River Site (SRS) will immobilize excess plutonium in the proposed Plutonium Immobilization Project (PIP). The PIP adds the excess plutonium to ceramic pucks, loads the pucks into cans, and places the cans into DWPF canisters. This paper discusses the PIP process steps, the can loading conceptual design, can loading equipment design, and can loading work completed.

  5. Zone refining of plutonium metal

    SciTech Connect

    Blau, M.S.

    1994-08-01

    The zone refining process was applied to Pu metal containing known amounts of impurities. Rod specimens of plutonium metal were melted into and contained in tantalum boats, each of which was passed horizontally through a three-turn, high-frequency coil in such a manner as to cause a narrow molten zone to pass through the Pu metal rod 10 times. The impurity elements Co, Cr, Fe, Ni, Np, U were found to move in the same direction as the molten zone as predicted by binary phase diagrams. The elements Al, Am, and Ga moved in the opposite direction of the molten zone as predicted by binary phase diagrams. As the impurity alloy was zone refined, {delta}-phase plutonium metal crystals were produced. The first few zone refining passes were more effective than each later pass because an oxide layer formed on the rod surface. There was no clear evidence of better impurity movement at the slower zone refining speed. Also, constant or variable coil power appeared to have no effect on impurity movement during a single run (10 passes). This experiment was the first step to developing a zone refining process for plutonium metal.

  6. Microstructural evolution of Fesbnd 22%Cr model alloy under thermal ageing and ion irradiation conditions studied by atom probe tomography

    NASA Astrophysics Data System (ADS)

    Korchuganova, Olesya A.; Thuvander, Mattias; Aleev, Andrey A.; Rogozhkin, Sergey V.; Boll, Torben; Kulevoy, Timur V.

    2016-08-01

    Nanostructure evolution during ion irradiation of two thermally aged binary Fee22Cr alloys has been investigated using atom probe tomography. Specimens aged at 500 °C for 50 and 200 h were irradiated by 5.6 MeV Fe ions at room temperature up to fluences of 0.3 × 1015 ions/cm2 and 1 × 1015 ions/cm2. The effect of irradiation on the material nanostructure was examined at a depth of 1 μm from the irradiated surface. The analysis of Cr radial concentration functions reveals that dense α‧-phase precipitates in the 200 h aged alloy become diffuse and thereby larger when subjected to irradiation. On the other hand, less Cr-enriched precipitates in the alloy aged for 50 h are less affected. The CreCr pair correlation function analysis shows that matrix inhomogeneity decreases under irradiation. Irradiation leads to a decrease in the number density of diffuse clusters, whereas in the case of well-developed precipitates it remains unchanged.

  7. Mechanical properties and 95 C aging characteristics of zircon-reinforced Zn-4Al-3Cu alloy

    SciTech Connect

    Li, B.J.; Chao, C.G.

    1996-03-01

    A process for preparing zinc alloy castings containing dispersions of zircon particles is described. Composites were prepared by stirring zircon particles in Zn-4Al-3Cu (ZAS) alloy melts and subsequently casting these melts in permanent molds. It was found that additions of zircon resulted in an increase in the sliding wear resistance and in the proportional limit in compression. The aging characteristics of the ZAS alloy have also been investigated by hardness tests, dilatometry technique, and transmission electron microscopy observations. There are two kinds of precipitates that occur during the aging process. The {alpha}-phase precipitates form the {eta} phase in the early stage of aging and the copper-rich {var_epsilon}-phase precipitates from the {eta} phase in the later stage of aging. Therefore, there are two peaks in the hardening curve caused by both {alpha}-phase and {var_epsilon}-phase precipitation. The {alpha}-phase precipitation induces the dimensional shrinkage, and the copper-rich {var_epsilon} phase precipitation results in dimensional expansion. Zircon particles existing in ZAS alloy reduce the maximum shrinkage from 353 {times} 10{sup {minus}6} for the monolith to 167 {times} 10{sup {minus}6} for the composite. Two groups of parallel {alpha}-phase plates had formed within the {eta} dendrite during aging at 95 C. The orientation relationship between the {alpha} phase and matrix was determined as [{bar 1}101]{sub {eta}}{parallel}[1{bar 1}0]{sub {alpha}}, (11{bar 2}0){sub {eta}}{parallel}(111){sub {alpha}}.

  8. Transmission electron microscopy study of precipitates in an artificially aged Al–12.7Si–0.7Mg alloy

    SciTech Connect

    Liu, Fang; Yu, Fuxiao; Zhao, Dazhi; Zuo, Liang

    2015-09-15

    An investigation of Al–12.7Si–0.7Mg alloy aged at 160 °C, 180 °C and 200 °C for 3 h was carried out in order to identify the precipitating phases. Regular transmission and high resolution electron microscopy (TEM and HREM) were employed for this purpose. The studies were focused on the dark spots and needle-shaped precipitates lying in (001){sub Al} plane. Based on the HREM observations, dark spots and needle-shaped precipitates have different characteristics. The results revealed that the ellipsoidal and needle-shaped precipitates along <100> direction of the matrix coexist in the alloy by tilting experiments at given aging condition. The ellipsoidal dark spot precipitates viewing along [001]{sub Al} is not cross-sectional image of needle-shaped precipitates along <001>{sub Al}. Needle-shaped precipitate is coherent with the matrix. The diffraction pattern associated with the ellipsoidal precipitates is consistent with β″ reported in literature. - Highlights: • Wrought Al–Si–Mg alloy has been investigated to identify the precipitating phases. • The ellipsoidal and needle-shaped precipitates coexist in wrought Al–Si–Mg alloy. • The needle-shaped and ellipsoidal precipitates exhibit different characteristics.

  9. A replica technique for extracting precipitates from neutron-irradiated or thermal-aged vanadium alloys for TEM analysis

    NASA Astrophysics Data System (ADS)

    Fukumoto, K.; Iwasaki, M.

    2014-06-01

    A carbon replica technique has been developed to extract precipitates from vanadium alloys. Using this technique, precipitation phases can be extracted from neutron-irradiated or thermal-aged V-4Cr-4Ti alloys. Precipitate identification using EDS X-ray analysis and electron diffraction was facilitated. Only NaCl type of Ti(OCN) precipitate was formed in the thermal-aged V-4Cr-4Ti alloys at 600 °C for 20 h and cation sub-lattice was only occupied by Ti atoms. However, the thin plate of precipitates with NaCl type of crystallographic structure could be seen in the V-4Cr-4Ti alloys irradiated at 593 °C in the JOYO fast reactor. The precipitate contained chromium and vanadium atoms on the cation sub-lattice as well as titanium atoms. It is considered that the phase of MX type (M = Ti, V, Cr and X = O, N, C) is a metastable phase under neutron irradiation.

  10. Creep-rupture behavior of seven iron-base alloys after long term aging at 760 deg in low pressure hydrogen

    NASA Technical Reports Server (NTRS)

    Witzke, W. R.; Stephens, J. R.

    1980-01-01

    Seven candidate iron-base alloys for heater tube application in the Stirling automotive engine were aged for 3500 hours at 760 C in argon and hydrogen. Aging degraded the tensile and creep-rupture properties. The presence of hydrogen during aging caused additional degradiation of the rupture strength in fine grain alloys. Based on current design criteria for the Mod 1 Stirling engine, N-155 and 19-9DL are considered the only alloys in this study with strengths adequate for heater tube service at 760 C.

  11. Effects of copper precipitation on the magnetic properties of aged copper-containing ferrous alloys

    NASA Astrophysics Data System (ADS)

    Lo, C. C. H.

    2012-05-01

    Formation of nano-sized copper precipitates induced by neutron irradiation has been identified as one of the primary causes of radiation embrittlement of reactor pressure vessel steels. Although it has been shown that magnetic properties are sensitive to these microstructural changes, fundamental understanding is yet to be developed before magnetic NDE techniques can be reliably employed to detect radiation damages. This paper reports on a systematic study of the effects of copper precipitation on magnetic properties using an Fe-1wt%Cu alloy as a model system. Magnetic hysteresis and Barkhausen effect measurements were performed on a series of FeCu samples aged for different periods of time to produce different extents of copper precipitation in an iron matrix. The magnetic properties, including coercivity, initial permeability, the Rayleigh constant and Barkhausen effect signal, were found to correlate with the sample hardness as a result of precipitation hardening. The empirical relationships between magnetic and mechanical properties are interpreted in terms of pinning of magnetic domain walls and dislocations by a network of randomly distributed copper precipitates.

  12. Aging of the Inconel 718 alloy between 500 and 750{degree}C

    SciTech Connect

    Slama, C.; Servant, C.; Cizeron, G.

    1997-09-01

    The aging of the NC 19 Fe Nb alloy (Inconel 718), previously quenched from 990{degree}C, is characterized by a hardness peak at 650{degree}C, then a maximum in hardness at about 750{degree}C. Over this temperature, the hardness progressively decreases. In the 550{endash}650{degree}C temperature range, TEM observations have revealed that {beta} (Ni{sub 3}Nb) precipitates are formed as long platelets parallel between them within the same grain, as well as extremely fine {gamma}{sup {prime}}[Ni{sub 3}(Ti,Al)] particles responsible for the observed improvement in hardness. For a tempering temperature higher than 650{degree}C, a first hardening occurs after a 4 h treatment, which has been associated with the {gamma}{sup {prime}} phase precipitation, with a more or less spherical shape. Beyond this time, a second hardening takes place linked to the {gamma}{sup {prime}{prime}} phase precipitation (Ni{sub 3}Nb, bct D0{sub 22} structure), as thin platelet shaped, perfectly coherent with the matrix. The misfit between the {gamma} and {gamma}{sup {prime}{prime}} phases is about 3{percent} in the {l_angle}001{r_angle}{gamma}{sup {prime}{prime}} direction and lower than 1{percent} in the {l_angle}100{r_angle}{gamma}{sup {prime}{prime}} and {l_angle}010{r_angle}{gamma}{sup {prime}{prime}} directions. During a longer aging at 750{degree}C, the {gamma}{sup {prime}{prime}} platelets progressively dissolve while {beta} precipitates grow. {copyright} {ital 1997 Materials Research Society.}

  13. Influence of Aging Treatments on Alterations of Microstructural Features and Stress Corrosion Cracking Behavior of an Al-Zn-Mg Alloy

    NASA Astrophysics Data System (ADS)

    Rout, Prasanta Kumar; Ghosh, M. M.; Ghosh, K. S.

    2015-07-01

    7xxx series Al-Zn-Mg-(Cu) alloys have higher strength in their peak-aged (T6) states compared with other age-hardenable aluminum alloys; however, the maximum strength peak-aged state is more susceptible to stress corrosion cracking (SCC) which leads to catastrophic failure. The over-aged (T7) temper with 10-15% lower strength has higher resistance to SCC requiring oversized structural aerospace component applications. The medium-strength AA7017 Al-Zn-Mg weldable alloy without Cu is also prone to SCC under certain environmental conditions. In the present investigation, the SCC behaviors of an AA7017 Al-Zn-Mg alloys of different tempers have been assessed. Specific aging schedules have been adapted to an AA7017 alloy to produce various tempers, e.g., under-, peak-(T6), over-(T7), and highly over-aged tempers. Artificial aging behavior of the AA7017 alloy has been characterized by hardness, electrical conductivity measurements, x-ray diffraction, differential scanning calorimetry, and electrochemical studies. Slow strain rate test technique was used to assess the SCC behaviors of the AA7017 alloys of under-, T6, T7, and highly over-aged tempers in 3.5 wt.% NaCl solution at free corrosion potential (FCP) and at applied anodic potential, as well. Results revealed that the AA7017 alloy tempers are not susceptible to SCC in 3.5 wt.% NaCl solution at FCP, but severely damaging to SCC at applied anodic potentials. Microstructural features, showing a non-recrystallized grain structure and the presence of discrete, widely spaced, not-interconnected η precipitates at the grain boundaries, are the contributive factors by virtue of which the alloy tempers at FCP did not exhibit SCC. However, the applied anodic potential resulted in rapid metal dissolution from the grain boundary region and led to SCC. The local anodic dissolution (LAD) is believed to be the associated SCC mechanism.

  14. Study on Variants of Solution Treatment and Aging Cycle of Titanium Alloy Ti6Al4V

    NASA Astrophysics Data System (ADS)

    Gupta, R. K.; Kumar, V. Anil; Chhangani, Sumit

    2016-04-01

    Ti6Al4V with two different chemical compositions, one rich and the other lean in α-stabilizer oxygen were selected to study the effect of quench severity during solution treatment and their aging response. These two coupons were taken from two differently processed wrought products viz. rolled ring and closed die forging. The coupons were then subjected to solution treatment followed by employing different cooling rates to vary the quench severity and different aging treatments by changing the aging temperature and time. The microstructure and mechanical properties thus obtained are correlated with respect to the heat treatment conditions. It is noted that there is a significant increase in strength of the alloy retaining the ductility when it is aged in the aging temperature regime of 550-650 °C and time of 8 h. Role of higher oxygen content is noted, which is more pronounced with higher severity of quench (by water quenching). Specimens representative of different heat treatment conditions were characterized using optical microscope, electron back-scattered diffraction, and electron microscope. The presence of martensitic (α') structure along with uniform distribution of fine primary α, secondary α precipitates and refined β-grains, twins in the microstructure helps in improving the strength of the material. Also, during high temperature aging of 700 °C, which incidentally falls in the range of annealing temperature of the alloy, overaging occurs which is similar to effect of annealing and hence retains the ductility as well.

  15. Aging Effect on Texture Evolution during Warm Rolling of ZK60 Alloys Fabricated by Twin-Roll Casting

    NASA Astrophysics Data System (ADS)

    Cho, Jae-Hyung; Chen, Hong-Mei; Choi, Shi-Hoon; Kim, Hyoung-Wook; Kang, Suk-Bong

    2010-10-01

    ZK60(Mg-Zn-Zr) alloys experience variation of precipitates during aging. The frequency and size of rod- and disk-shaped precipitates change with aging. The effect of aging on texture evolution during warm rolling of ZK60 was investigated. Some difference was found between the texture evolution of solution heat-treated (T4) and artificially aged (T6) samples. The Aged samples had more texture variations along the thickness direction than solution heat-treated samples. The intensities of basal fibers were lower during asymmetric rolling than during symmetric rolling, although the initial intensities increased during both rolling processes. The decrease in basal fibers by asymmetric rolling was clearer at a lower temperature of 448 K (175 °C) than at 498 K (225 °C).

  16. Effect of Postweld Aging Treatment on Fatigue Behavior of Pulsed Current Welded AA7075 Aluminum Alloy Joints

    NASA Astrophysics Data System (ADS)

    Balasubramanian, V.; Ravisankar, V.; Madhusudhan Reddy, G.

    2008-04-01

    This article reports the effect of postweld aging treatment on fatigue behavior of pulsed current welded AA 7075 aluminum alloy joints. AA7075 aluminum alloy (Al-Zn-Mg-Cu alloy) has gathered wide acceptance in the fabrication of light weight structures requiring high strength-to weight ratio, such as transportable bridge girders, military vehicles, road tankers, and railway transport systems. The preferred welding processes of AA7075 aluminum alloy are frequently gas tungsten arc welding (GTAW) process and gas metal arc welding (GMAW) process due to their comparatively easier applicability and better economy. Weld fusion zones typically exhibit coarse columnar grains because of the prevailing thermal conditions during weld metal solidification. This often results inferior weld mechanical properties and poor resistance to hot cracking. In this investigation, an attempt has been made to refine the fusion zone grains by applying pulsed current welding technique. Rolled plates of 10 mm thickness have been used as the base material for preparing multipass welded joints. Single V butt joint configuration has been prepared for joining the plates. The filler metal used for joining the plates is AA 5356 (Al-5Mg (wt.%)) grade aluminum alloy. Four different welding techniques have been used to fabricate the joints and they are: (i) continuous current GTAW (CCGTAW), (ii) pulsed current GTAW (PCGTAW), (iii) continuous current GMAW (CCGMAW), and (iv) pulsed current GMAW (PCGMAW) processes. Argon (99.99% pure) has been used as the shielding gas. Rotary bending fatigue testing machine has been used to evaluate fatigue behavior of the welded joints. Current pulsing leads to relatively finer and more equi-axed grain structure in GTA and GMA welds. Grain refinement is accompanied by an increase in fatigue life and endurance limit. Simple postweld aging treatment applied to the joints is found to be beneficial to enhance the fatigue performance of the welded joints.

  17. Microstructural evolution of a lead-free solder alloy Sn-Bi-Ag-Cu prepared by mechanical alloying during thermal shock and aging

    NASA Astrophysics Data System (ADS)

    Huang, M. L.; Wu, C. M. L.; Lai, J. K. L.; Chan, Y. C.

    2000-08-01

    In a previous study, a lead-free solder, Sn-6Bi-2Ag-0.5Cu, was developed by mechanical alloying. The alloy shows great potential as a lead-free solder system. In the present work, the microstructural evolution during thermal shock and aging was examined. In the as-soldered joints small bismuth (1 µm to 2 µm) and Ag3Sn (1 µm) particles were finely dispersed in a nearly pure tin matrix with a small amount of η-Cu6Sn5 phase in the bulk of solder. During thermal shock and aging microstructural evolution occurred with Cu-Sn intermetallic compound (IMC) layer growth at interface, bismuth phase coarsening and Ag3Sn phase coarsening. The microstructure of the solder appeared to be stable at high temperature. The shear strength of the present solder joint is higher than that of Sn-37Pb and Sn-3.5Ag solders. Shear failure occurred Cu-Sn IMC layer-solder interface and in the bulk of solder.

  18. METHOD AND MEANS FOR ELECTROLYTIC PURIFICATION OF PLUTONIUM

    DOEpatents

    Bjorklund, C.W.; Benz, R.; Maraman, W.J.; Leary, J.A.; Walsh, K.A.

    1960-02-01

    The technique of electrodepositing pure plutonium from a fused salt electrolyte of PuCl/sub 3/ and aixati metal halides is described. When an iron cathode is used, the plutonium deposit alloys therewith in the liquid state at the 400 to 600 deg C operating temperature, such liquid being allowed to drip through holes in the cathode and collect in a massive state in a tantallum cup. The process is adaptable to continuous processing by the use of depleted plutonium fuel as the anode: good to excellent separation from fission products is obtained with a Pu--Fe "fission" anode containing representative fractions of Ce, Ru, Zr, La, Mo, and Nb.

  19. Low-Temperature Aging Kinetics of a 15-Year Old Water-Quenched U-6wt.% Nb Alloy

    SciTech Connect

    Hsiung, L; Zhou, J

    2007-10-30

    It is well known that U-6wt.% Nb (U-14at.% Nb) alloy has a microstructure containing martensitic phases supersaturated with Nb that can be obtained by rapid quenching the alloy from {gamma} (bcc)-field solid solution to room temperature. The high cooling rate forces the {gamma}-phase solid solution to transform to variants of the low-temperature {alpha} (orthorhombic) phase in which Nb is forced to retain in the supersaturated solid solution. However, the crystal lattice of supersaturated solution formed by rapid quenching is in unstable conditions and is severely distorted since the solubility of Nb in the {alpha} phase at room temperature is nearly zero under an equilibrium condition. Two variant phases, a monoclinic distortion of {alpha} phase that is designated as {alpha}{double_prime} martensite and a tetragonal distortion of {gamma} phase that is designated as {gamma}{sup o} phase, can form in the as-quenched alloy, as shown in Fig. 1. We have learned from our previous TEM studies on the low-temperature aging of a water-quenched U6Nb (WQ-U6Nb) alloy that there are two possible transformation pathways for phase decomposition of the alloy supersaturated with 14 at.% of Nb upon aging at temperatures below 200 C, i.e., (1) supersaturated solid solution {alpha}{double_prime} {yields} spinodal decomposition {yields} {alpha}{sub 1} (Nb-lean) + {alpha}{sub 2} (Nb-rich) at 200 C and (2) supersaturated solid solution {alpha}{double_prime} {yields} spinodal ordering {yields}{alpha}{double_prime}{sub po} (partially ordered phase) {yields} phase decomposition and precipitation {yields} {alpha} (U) + {alpha}{sub o} (U{sub 3}Nb) at ambient temperatures [1]. The mechanisms for the spinodal transformation occurred at 200 C and the spinodal ordering occurred at ambient temperatures are quite similar; both are caused by the composition modulation of Nb except that the wavelength ({lambda} {approx} 3 nm) of modulation for spinodal decomposition is larger than that ({lambda

  20. A New Aging Treatment for Improving Cryogenic Toughness of the Main Structural Alloy of the Super Lightweight Tank

    NASA Technical Reports Server (NTRS)

    Chen, P. S.; Stanton, W. P.

    1996-01-01

    Marshall Space Flight Center (MSFC) has developed a new technique that can enhance cryogenic fracture toughness and reduce the statistical spread of toughness values in alloy 2195. This aging treatment can control the location and size of strengthening precipitate T1, making improvements possible in cryogenic fracture toughness (CFT) and fracture toughness ratio (FTR). At the start of this program, design of experiments (DOE) ingot No. 10 was used as a baseline for aging process development and optimization. The new aging treatment was found to be very effective, improving CFT by approximately 15 to 20 percent for DOE ingot No. 10. To further evaluate the repeatability and effectiveness of this new treatment, the investigators selected and tested three more lots of alloy 2195, using 1.75-in-thick gauge plates with FTR values ranging from 0.85 to 1.07. The new aging treatment effectively enhanced CFT and FTR values for all three lots. In one instance, the material was considered rejectable because it did not meet the minimum FTR value (1.0) of the super lightweight tank (SLWT). The new aging treatment improved its FTR from 0.85 to 1.01, making this material acceptable for use in the SLWT.

  1. Effect of High Temperature Aging on the Corrosion Resistance of Iron Based Amorphous Alloys

    SciTech Connect

    Day, S D; Haslam, J J; Farmer, J C; Rebak, R B

    2007-08-10

    Iron-based amorphous alloys can be more resistant to corrosion than polycrystalline materials of similar compositions. However, when the amorphous alloys are exposed to high temperatures they may recrystallize (or devitrify) thus losing their resistance to corrosion. Four different types of amorphous alloys melt spun ribbon specimens were exposed to several temperatures for short periods of time. The resulting corrosion resistance was evaluated in seawater at 90 C and compared with the as-prepared ribbons. Results show that the amorphous alloys can be exposed to 600 C for 1-hr. without losing the corrosion resistance; however, when the ribbons were exposed at 800 C for 1-hr. their localized corrosion resistance decreased significantly.

  2. Effect of Aging Treatment on the Damping Capacity and Mechanical Properties of Mg-6Al-1Zn Alloy

    PubMed Central

    El-Morsy, Abdel-Wahab; Farahat, Ahmed I. Z.

    2015-01-01

    The damping capacity and mechanical properties of Mg-6Al-1Zn alloy after heat treatment were investigated. The damping characteristics of un-heat-treated, solution treated, and aged Mg-6Al-1Zn specimens were determined by measuring the damping ratio and the logarithmic decrement of free vibrations of a bending beam clamped at one side. The microstructural evaluations confirmed that the β-Mg17Al12 phase was reprecipitated after aging and increased with an increase in aging time. The peak level of damping ratio and logarithmic decrement was obtained after 34 hr of aging time, over which the damping capacity declined according to increasing amount of strong pining points. PMID:25918738

  3. The Microstructural Evolution of Inconel Alloy 740 During Solution Treatment, Aging, and Exposure at 760 °C

    SciTech Connect

    Cowen, Christopher J.; Danielson, Paul E.; Jablonski, Paul D.

    2010-08-10

    In this study, the microstructural evolution of Inconel alloy 740 during solution treatment and aging was characterized using optical and scanning electron microscopy. During double solution heat treatment, carbon is liberated from the dissolution of MC carbides during the first solution treatment at 1150 °C, and fine MC carbides are precipitated on gamma grain boundaries during the second solution treatment at 1120 °C. Due to the concurrent decrease in carbon solubility and the increase in the contribution of grain boundary diffusion at lower temperatures, the MC carbides on the gamma grain boundaries provide a localized carbon reservoir that aids in M23C6 carbide precipitation on gamma grain boundaries during exposure at 760 °C. The γ' phase, which is the key strengthening phase in alloy 740, is incorporated into the alloy microstructure during aging at 850 °C. Finally, the main source of microstructural instability observed during exposure at 760 °C was the coarsening of the γ' phase.

  4. Influence of Li Addition to Zn-Al Alloys on Cu Substrate During Spreading Test and After Aging Treatment

    NASA Astrophysics Data System (ADS)

    Gancarz, Tomasz; Pstrus, Janusz; Cempura, Grzegorz; Berent, Katarzyna

    2016-08-01

    The spreading of Zn-Al eutectic-based alloys with 0.05 wt.%, 0.1 wt.%, and 0.2 wt.% Li on Cu substrate has been studied using the sessile drop method in presence of QJ201 flux. Wetting tests were performed after 1 min, 3 min, 8 min, 15 min, 30 min, and 60 min of contact at temperatures of 475°C, 500°C, 525°C, and 550°C. Samples after spreading at 500°C for 1 min were subjected to aging for 1 day, 10 days, and 30 days at temperature of 120°C, 170°C, and 250°C. The spreadability of eutectic Zn-5.3Al alloy with different Li contents on Cu substrate was determined in accordance with ISO 9455-10:2013-03. Selected solidified solder-substrate couples were, after spreading and aging tests, cross-sectioned and subjected to scanning electron microscopy, energy-dispersive spectroscopy (EDS), and x-ray diffraction (XRD) analysis of the interfacial microstructure. An experiment was designed to demonstrate the effect of Li addition on the kinetics of the formation and growth of CuZn, Cu5Zn8, and CuZn4 intermetallic compound (IMC) phases, during spreading and aging. The IMC layers formed at the interface were identified using XRD and EDS analyses. Increasing addition of Li to Zn-Al alloy caused a reduction in the thickness of the IMC layer at the interface during spreading, and an increase during aging. The activation energy was calculated, being found to increase for the Cu5Zn8 phase but decrease for the CuZn and CuZn4 phases with increasing Li content in the Zn-Al-Li alloys. The highest value of 142 kJ mol-1 was obtained for Zn-Al with 1.0 Li during spreading and 69.2 kJ mol-1 for Zn-Al with 0.05 Li during aging. Aging at 250°C caused an increase in only the Cu5Zn8 layer, which has the lowest Gibbs energy in the Cu-Zn system. This result is connected to the high diffusion of Cu from the substrate to the solder.

  5. Three-step aging to obtain high strength and corrosion resistance in Al-Zn-Mg-Cu alloys

    SciTech Connect

    Brown, M.H.

    1984-10-16

    A three-step thermal aging method for improving the strength and corrosion resistance of an article comprising a solution heat treated aluminum alloy containing zinc, magnesium, copper and at least one element selected from the group consisting of chromium, manganese and zirconium. The article is precipitation hardened at about 175/sup 0/ to 325/sup 0/ F., heat treated for from several minutes to a few hours at a temperature of about 360/sup 0/ to 390/sup 0/ F. and again precipitation hardened at about 175/sup 0/ to 325/sup 0/ F. In a preferred embodiment the article treated comprises aluminum alloy 7075 in the T6 condition. The method of the invention is easier to control and is suitable for treating articles of greater thickness than other comparable methods.

  6. PREPARATION OF PLUTONIUM HALIDES

    DOEpatents

    Davidson, N.R.; Katz, J.J.

    1958-11-01

    A process ls presented for the preparation of plutonium trihalides. Plutonium oxide or a compound which may be readily converted to plutonlum oxide, for example, a plutonium hydroxide or plutonlum oxalate is contacted with a suitable halogenating agent. Speciflc agents mentioned are carbon tetrachloride, carbon tetrabromide, sulfur dioxide, and phosphorus pentachloride. The reaction is carried out under superatmospberic pressure at about 300 icient laborato C.

  7. METHOD OF SEPARATING PLUTONIUM

    DOEpatents

    Heal, H.G.

    1960-02-16

    BS>A method of separating plutonium from aqueous nitrate solutions of plutonium, uranium. and high beta activity fission products is given. The pH of the aqueous solution is adjusted between 3.0 to 6.0 with ammonium acetate, ferric nitrate is added, and the solution is heated to 80 to 100 deg C to selectively form a basic ferric plutonium-carrying precipitate.

  8. FRACTURE TOUGHNESS OF 9Cr-1MoV AND THERMALLY AGED ALLOY 617 FOR ADVANCED REACTOR APPLICATIONS

    SciTech Connect

    Nanstad, Randy K; Sokolov, Mikhail A; Chen, Xiang

    2012-01-01

    Nickel-base Alloy 617 is being considered as a structural material for application in the secondary heat exchanger of the New Generation Nuclear Plant, a very high temperature gas-cooled reactor. Thermal aging of Alloy 617 plate and welds is being performed with tensile, Charpy impact, and fracture toughness tests conducted at temperatures to 950 C. Results of testing for thermal aging to 5,300 h have been obtained and are presented; varying effects of thermal aging temperature and time on fracture toughness are observed. The 9Cr-1MoV (Grade 91) ferritic steel is a candidate for structural applications in the sodium fast reactor. Fracture toughness testing of unaged Grade 91 steel has been performed to evaluate specimen size effects in preparation for future testing of the material in the thermally aged condition. Results for material in the mill-annealed and heat treated conditions are presented and show that this heat of Grade 91 steel does not indicate a small specimen bias on the fracture toughness Master Curve reference temperature.

  9. Initial precipitation and hardening mechanism during non-isothermal aging in an Al–Mg–Si–Cu 6005A alloy

    SciTech Connect

    Yang, Wenchao; Ji, Shouxun; Huang, Lanping; Sheng, Xiaofei; Li, Zhou; Wang, Mingpu

    2014-08-15

    The characterization of precipitation and hardening mechanism during non-isothermal aging had been investigated using high resolution transmission electron microscopy for an Al–Mg–Si–Cu 6005A alloy. It was proposed that the needle-shaped β″ precipitates with a three-dimension coherency strain-field and an increased number density in the Al matrix provided the maximum strengthening effect for the Al–Mg–Si–Cu 6005A alloy. Simultaneously, it was also found that the formation and evolution of clusters in the early precipitation were associated with the vacancy binding energy, during which Si atoms played an important role in controlling the numbers density of Mg/Si co-clusters, and the excess Si atoms provided the increased number of nucleation sites for the subsequent precipitates to strengthen and improve the precipitation rate. Finally, based on the experimental observation and theoretical analysis, the precipitation sequence during the early precipitation in the Al–Mg–Si–Cu 6005A alloy was proposed as: supersaturated solid solution → Si-vacancy pairs, Mg-vacancy pairs and Mg clusters → Si clusters, and dissolution of Mg clusters → Mg atoms diffusion into the existing Si clusters → Mg/Si co-clusters → GP zone. - Highlights: • β″ precipitates provide the maximum strengthening effect for the 6005A alloy. • Si atoms play an important role in controlling the numbers of Mg/Si co-clusters. • The early aging sequence is deduced based on the solute-vacancy binding energy.

  10. PREPARATION OF PLUTONIUM

    DOEpatents

    Kolodney, M.

    1959-07-01

    Methods are presented for the electro-deposition of plutonium from fused mixtures of plutonium halides and halides of the alkali metals and alkaline earth metals. Th salts, preferably chlorides and with the plutonium prefer ably in the trivalent state, are placed in a refractory crucible such as tantalum or molybdenam and heated in a non-oxidizing atmosphere to 600 to 850 deg C, the higher temperatatures being used to obtain massive plutonium and the lower for the powder form. Electrodes of graphite or non reactive refractory metals are used, the crucible serving the cathode in one apparatus described in the patent.

  11. Continuous plutonium dissolution apparatus

    DOEpatents

    Meyer, F.G.; Tesitor, C.N.

    1974-02-26

    This invention is concerned with continuous dissolution of metals such as plutonium. A high normality acid mixture is fed into a boiler vessel, vaporized, and subsequently condensed as a low normality acid mixture. The mixture is then conveyed to a dissolution vessel and contacted with the plutonium metal to dissolve the plutonium in the dissolution vessel, reacting therewith forming plutonium nitrate. The reaction products are then conveyed to the mixing vessel and maintained soluble by the high normality acid, with separation and removal of the desired constituent. (Official Gazette)

  12. Trawsfynydd Plutonium Estimate

    SciTech Connect

    Reid, Bruce D.; Gerlach, David C.; Heasler, Patrick G.; Livingston, J.

    2009-11-20

    Report serves to document an estimate of the cumulative plutonium production of the Trawsfynydd Unit II reactor (Traws II) over its operating life made using the Graphite Isotope Ratio Method (GIRM). The estimate of the plutonium production in Traws II provided in this report has been generated under blind conditions. In other words, the estimate ofthe Traws II plutonium production has been generated without the knowledge of the plutonium production declared by the reactor operator (Nuclear Electric). The objective of this report is to demonstrate that the GIRM can be employed to serve as an accurate tool to verify weapons materials production declarations.

  13. Effects of Welding Processes and Post-Weld Aging Treatment on Fatigue Behavior of AA2219 Aluminium Alloy Joints

    NASA Astrophysics Data System (ADS)

    Malarvizhi, S.; Balasubramanian, V.

    2011-04-01

    AA2219 aluminium alloy square butt joints without filler metal addition were fabricated using gas tungsten arc welding (GTAW), electron beam welding (EBW), and friction stir welding (FSW) processes. The fabricated joints were post-weld aged at 175 °C for 12 h. The effect of three welding processes and post-weld aging (PWA) treatment on the fatigue properties is reported. Transverse tensile properties of the welded joints were evaluated. Microstructure analysis was also carried out using optical and electron microscopes. It was found that the post-weld aged FSW joints showed superior fatigue performance compared to EBW and GTAW joints. This was mainly due to the formation of very fine, dynamically recrystallized grains and uniform distribution of fine precipitates in the weld region.

  14. Changes in the magnetic and mechanical properties of thermally aged Fe-Cu alloys due to nano-sized precipitates

    NASA Astrophysics Data System (ADS)

    Li, Yi; Li, Yuanfei; Deng, Shanquan; Xu, Ben; Li, Qiulin; Shu, Guogang; Liu, Wei

    2016-01-01

    The changes in the magnetic properties, mechanical properties, and microstructural parameters of Fe-Cu alloys due to thermal aging have been investigated to improve the fundamental understanding of using magnetic technology for the nondestructive evaluation (NDE) of irradiation embrittlement in the reactor pressure vessel (RPV). Nano-sized Cu particles precipitated from a Fe matrix after thermal aging at 500 °C for various times, and the microstructure parameters were determined. The coercivity, Barkhausen noise (BN), Vickers hardness, and yield stress were also measured for these samples. These properties show the same hardening-softening trend with increasing aging time, which can be interpreted in terms of the microstructure parameters evolution based on the model of the pinning of precipitates on domain walls and dislocations. These results suggest the practicability of using magnetic technology for the NDE of the irradiation embrittlement of the RPV.

  15. Study of aging effects in a Ti-6AL-4V alloy with Widmanstätten and equiaxed microstructures by non-destructive means

    SciTech Connect

    Carreon, Hector; Ruiz, Alberto; Santoveña, Bayron

    2014-02-18

    When the Ti-6Al-4V alloy is over-aged at 500-600°C, nanometer-sized α{sub 2} (Ti{sub 3}Al) phases can be homogeneously precipitated inside α phases, thereby leading to the additional improvement of mechanical properties. The present study was concerned with the effects of over-aging on thermoelectric power (TEP) measurements in a Ti-6Al-4V alloy. Widmanstätten and equiaxed microstructures containing fine and agr{sub 2} (Ti{sub 3}Al) particles were obtaining by over-aging a Ti-6Al-4V alloy. Over-aging heat treatments were conducted at 515°C, 545°C and 575°C for different aging times. In order to find out the factors affecting the variation in the TEP, the over-aging samples were examined by optical microscopy (OM) and (SEM) scanning electron microscopy. In particular, we studied the behavior of the physical material property hardness, an important parameter of the Ti-6Al-4V alloy mechanical properties, with respect to the variation in the aging time and temperature. It was found that the TEP measurements reveal an increase in the magnitude of the absolute TEP value of the over-aged Widmanstätten and equiaxed microstructures with regards to the unaged condition for different aging times, with a somewhat higher value at 515°C.

  16. Study of aging effects in a Ti-6AL-4V alloy with Widmanstätten and equiaxed microstructures by non-destructive means

    NASA Astrophysics Data System (ADS)

    Carreon, Hector; Ruiz, Alberto; Santoveña, Bayron

    2014-02-01

    When the Ti-6Al-4V alloy is over-aged at 500-600°C, nanometer-sized α2 (Ti3Al) phases can be homogeneously precipitated inside α phases, thereby leading to the additional improvement of mechanical properties. The present study was concerned with the effects of over-aging on thermoelectric power (TEP) measurements in a Ti-6Al-4V alloy. Widmanstätten and equiaxed microstructures containing fine &agr2 (Ti3Al) particles were obtaining by over-aging a Ti-6Al-4V alloy. Over-aging heat treatments were conducted at 515°C, 545°C and 575°C for different aging times. In order to find out the factors affecting the variation in the TEP, the over-aging samples were examined by optical microscopy (OM) and (SEM) scanning electron microscopy. In particular, we studied the behavior of the physical material property hardness, an important parameter of the Ti-6Al-4V alloy mechanical properties, with respect to the variation in the aging time and temperature. It was found that the TEP measurements reveal an increase in the magnitude of the absolute TEP value of the over-aged Widmanstätten and equiaxed microstructures with regards to the unaged condition for different aging times, with a somewhat higher value at 515°C.

  17. Comparative evaluation of shear bond strengths of veneering porcelain to base metal alloy and zirconia substructures before and after aging – An in vitro study

    PubMed Central

    Sreekala, Laju; Narayanan, Mahesh; Eerali, Sunil M.; Eerali, Susil M.; Varghese, Joju; Zainaba Fathima, A. l.

    2015-01-01

    Objective: The aim of this study was to evaluate and compare the shear bond strength of veneering porcelain to base metal alloy and zirconia substructures before and after aging. Scanning electron microscopy (SEM) was used to determine the failure pattern. Materials and Methods: Twenty rectangular blocks (9 mm length × 4 mm height × 4 mm width) of base metal alloy (Bellabond plus, Bego, Germany) and zirconia (Will ceramZ zirconia K block) were fabricated for shear bond strength test. Surface of the base metal alloy block (4 mm × 4 mm area) was veneered with corresponding veneering porcelain (Ivoclar, IPS classic, vivadent). Similarly, surface of the zirconia rectangular block (4 mm × 4 mm) was veneered with corresponding veneering ceramic (Cercon ceram kiss, Degudent). Out of forty rectangular porcelain veneered core specimen, ten porcelain veneered base metal alloy specimen and ten porcelain veneered zirconia specimen were immersed in water at 37°C for one month to simulate the oral environment. Results: On comparison, the highest shear bond strength value was obtained in porcelain veneered base metal alloy before aging group followed by porcelain veneered base metal alloy after aging group, Porcelain veneered zirconia before aging group, porcelain veneered zirconia after aging group. SEM analysis revealed predominantly cohesive failure of veneering ceramic in all groups. Conclusion: Porcelain veneered base metal alloy samples showed highest shear bond strength than porcelain veneered zirconia samples. Study concluded that aging had an influence on shear bond strength. Shear bond strength was found to be decreasing after aging. SEM analysis revealed cohesive failure of veneering ceramic in all groups suggestive of higher bond strength of the interface than cohesive strength of ceramic. Hence, it was concluded that veneering ceramic was the weakest link. PMID:26942121

  18. Study of the SCC Behavior of 7075 Aluminum Alloy After One-Step Aging at 163 °C

    NASA Astrophysics Data System (ADS)

    Silva, G.; Rivolta, B.; Gerosa, R.; Derudi, U.

    2013-01-01

    For the past many years, 7075 aluminum alloys have been widely used especially in those applications for which high mechanical performances are required. It is well known that the alloy in the T6 condition is characterized by the highest ultimate and yield strengths, but, at the same time, by poor stress corrosion cracking (SCC) resistance. For this reason, in the aeronautic applications, new heat treatments have been introduced to produce T7X conditions, which are characterized by lower mechanical strength, but very good SCC behavior, when compared with the T6 condition. The aim of this study is to study the tensile properties and the SCC behavior of 7075 thick plates when submitted to a single-step aging by varying the aging times. The tests were carried out according to the standards and the data obtained from the SCC tests were analyzed quantitatively using an image analysis software. The results show that, when compared with the T7X conditions, the single-step aging performed in the laboratory can produce acceptable tensile and SCC properties.

  19. The Influence of Dynamic Strain Aging on Fatigue and Creep-Fatigue Characterization of Nickel-Base Solid Solution Strengthened Alloys

    SciTech Connect

    L.J. Carroll; W.R. Lloyd; J.A. Simpson; R.N. Wright

    2010-12-01

    The nickel-base solid solution alloys, Alloy 617 and Alloy 230, have been observed to exhibit serrated yielding or dynamic strain aging (DSA) in a temperature/strain rate regime of interest for intermediate heat exchangers (IHX) of high temperature nuclear reactors. At 800°C, these nickel-base alloys are prone to large serrated yielding events at relatively low strains. The presence of DSA introduces challenges in characterizing the creep-fatigue and low cycle fatigue behavior. These challenges include inability to control the target strains as a result of DSA induced strain excursions and distorted hysteresis loops. Methods to eliminate or reduce the influence of DSA on creep-fatigue testing have been investigated, including varying the strain rate, stepping to the target strain, and adjusting servo-hydraulic tuning parameters. It has not been possible to eliminate the impact of serrated flow in the temperature range of interest for these alloys without compromising the desired test protocols.

  20. Friction stir welding of thin-sheet, age-hardenable aluminum alloys: A study of process/structure/property relationships

    NASA Astrophysics Data System (ADS)

    Shukla, Alpesh Khushalchand

    Friction Stir Welding (FSW) is a relatively new joining process that, as a solid-state process, offers several advantages over conventional fusion welding. Although FSW has been used extensively for the joining of age-hardenable aluminum alloys, the detailed effects of process parameters on the microstructures and mechanical properties of these welds have not been studied, especially for thin-sheet alloys. The present study investigated the FSW of thin-sheet, age-hardenable aluminum alloys, including: the development and optimization of welding process parameters that produce high-integrity, defect-free welds; the systematic evaluation of the effect of the base metal microstructure, FSW process parameters, and corresponding weld zone thermal conditions on microstructure evolution across the weld zone; the analysis of FSW mechanical properties and fracture behavior; and the development of relationships between the process parameters, microstructure, properties, and fracture that allow the optimization of weld performance. Two alloy systems, viz., Al-Cu-Mg (2024) and Al-Cu-Li (2195) in naturally-aged and artificially-aged conditions, respectively, were studied. Process optimization in 1 mm thick 2024-T3 sheet resulted in superior properties versus those of FS welds in thick sheet and plate, and nearly 100% joint efficiency. Microstructures, hardness and tensile properties of FS welds in 2024-T3 exhibited a strong dependency on process parameters. The heat of welding promoted various weld zone microstructures that were produced via the dissolution of base metal GPB zones, the nucleation of GBP and GPB II, and the nucleation and coarsening of S phase. SZ hardness for 2024-T3 welds exhibited a strong, but unusual dependency on the FSW process parameters, which was related to different mechanisms related to GPB zone formation. The microstructures of FS welds in 1 mm thick 2195-T8 were generally insensitive to the FSW process parameters. For all weld heat inputs, FSW

  1. Friction Stir Welding of Age-Hardenable Aluminum Alloys: A Parametric Approach Using RSM Based GRA Coupled With PCA

    NASA Astrophysics Data System (ADS)

    Vijayan, D.; Rao, V. S.

    2014-04-01

    Age-hardenable aluminum alloys, primarily used in the aerospace, automobile and marine industries (2×××, 6××× and 7×××), can be welded using solid-state welding techniques. Friction stir welding is an emerging solid-state welding technique used to join both similar and dissimilar materials. The strength of a friction stir welded joint depends on the joining process parameters. Therefore, a combination of the statistical techniques of a response surface methodology based on a grey relational analysis coupled to a principal component analysis was proposed to select the process parameters suitable for joining AA 2024 and AA 6061 aluminum alloys via friction stir welding. The significant process parameters, such as rotational speed, welding speed, axial load and pin shapes (PS) were considered during the statistical experiment. The results indicate that the square PS plays a vital role and yields an ultimate tensile strength of 141 MPa for an elongation of 12 % versus cylinder and taper pin profiles. The root cause for joint strength loss and fracture mode was analyzed using scanning electron microscopy. Severe material flow during macro defects, such as pin holes and porosity, degrades the joint strength by approximately 44 % for AA 2024 and 51 % for AA 6061 fabricated FS-welded aluminum alloys relative to the base material. The results of this approach are useful for accurately controlling the response and optimize the process parameters.

  2. ELECTRODEPOSITION OF PLUTONIUM

    DOEpatents

    Wolter, F.J.

    1957-09-10

    A process of electrolytically recovering plutonium from dilute aqueous solutions containing plutonium ions comprises electrolyzing the solution at a current density of about 0.44 ampere per square centimeter in the presence of an acetate-sulfate buffer while maintaining the pH of the solution at substantially 5 and using a stirred mercury cathode.

  3. PROCESS OF OXIDIZING PLUTONIUM

    DOEpatents

    Coryell, C.D.

    1959-08-25

    The oxidation of plutonium to the plus six valence state is described. The oxidation is accomplished by treating the plutonium in aqueous solution with a solution above 0.01 molar in argentic ion, above 1.1 molar in nitric acid, and above 0.02 molar in argentous ion.

  4. Plutonium storage criteria

    SciTech Connect

    Chung, D.; Ascanio, X.

    1996-05-01

    The Department of Energy has issued a technical standard for long-term (>50 years) storage and will soon issue a criteria document for interim (<20 years) storage of plutonium materials. The long-term technical standard, {open_quotes}Criteria for Safe Storage of Plutonium Metals and Oxides,{close_quotes} addresses the requirements for storing metals and oxides with greater than 50 wt % plutonium. It calls for a standardized package that meets both off-site transportation requirements, as well as remote handling requirements from future storage facilities. The interim criteria document, {open_quotes}Criteria for Interim Safe Storage of Plutonium-Bearing Solid Materials{close_quotes}, addresses requirements for storing materials with less than 50 wt% plutonium. The interim criteria document assumes the materials will be stored on existing sites, and existing facilities and equipment will be used for repackaging to improve the margin of safety.

  5. Plutonium Immobilization Canister Loading

    SciTech Connect

    Hamilton, E.L.

    1999-01-26

    This disposition of excess plutonium is determined by the Surplus Plutonium Disposition Environmental Impact Statement (SPD-EIS) being prepared by the Department of Energy. The disposition method (Known as ''can in canister'') combines cans of immobilized plutonium-ceramic disks (pucks) with vitrified high-level waste produced at the SRS Defense Waste Processing Facility (DWPF). This is intended to deter proliferation by making the plutonium unattractive for recovery or theft. The envisioned process remotely installs cans containing plutonium-ceramic pucks into storage magazines. Magazines are then remotely loaded into the DWPF canister through the canister neck with a robotic arm and locked into a storage rack inside the canister, which holds seven magazines. Finally, the canister is processed through DWPF and filled with high-level waste glass, thereby surrounding the product cans. This paper covers magazine and rack development and canister loading concepts.

  6. Electronic structure, phase transitions and diffusive properties of elemental plutonium

    NASA Astrophysics Data System (ADS)

    Setty, Arun; Cooper, B. R.

    2003-03-01

    We present a SIC-LDA-LMTO based study of the electronic structure of the delta, alpha and gamma phases of plutonium, and also of the alpha and gamma phases of elemental cerium. We find excellent agreement with the experimental densities and magnetic properties [1]. Furthermore, detailed studies of the computational densities of states for delta plutonium, and comparison with the experimental photoemission spectrum [2], provide evidence for the existence of an unusual fluctuating valence state. Results regarding the vacancy formation and self-diffusion in delta plutonium will be presented. Furthermore, a study of interface diffusion between plutonium and steel (technologically relevant in the storage of spent fuel) or other technologically relevant alloys will be included. Preliminary results regarding gallium stabilization of delta plutonium, and of plutonium alloys will be presented. [1] M. Dormeval et al., private communication (2001). [2] A. J. Arko, J. J. Joyce, L. Morales, J. Wills, and J. Lashley et. al., Phys. Rev. B, 62, 1773 (2000). [3] B. R. Cooper et al, Phil. Mag. B 79, 683 (1999); B.R. Cooper, Los Alamos Science 26, 106 (2000)); B.R. Cooper, A.K. Setty and D.L.Price, to be published.

  7. 31. VIEW OF A WORKER HOLDING A PLUTONIUM 'BUTTON.' PLUTONIUM, ...

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

    31. VIEW OF A WORKER HOLDING A PLUTONIUM 'BUTTON.' PLUTONIUM, A MAN-MADE SUBSTANCE, WAS RARE. SCRAPS RESULTING FROM PRODUCTION AND PLUTONIUM RECOVERED FROM RETIRED NUCLEAR WEAPONS WERE REPROCESSED INTO VALUABLE PURE-PLUTONIUM METAL (9/19/73). - Rocky Flats Plant, Bounded by Indiana Street & Routes 93, 128 & 72, Golden, Jefferson County, CO

  8. Creep-rupture behavior of candidate Stirling engine alloys after long-term aging at 760 deg C in low-pressure hydrogen

    NASA Technical Reports Server (NTRS)

    Titran, R. H.

    1984-01-01

    Nine candidate Stirling automotive engine alloys were aged at 760 C for 3500 hr in low pressure hydrogen or argon to determine the resulting effects on mechanical behavior. Candidate heater head tube alloys were CG-27, W545, 12RN72, INCONEL-718, and HS-188 while candidate cast cylinder-regenerator housing alloys were SA-F11, CRM-6D, XF-818, and HS-31. Aging per se is detrimental to the creep rupture and tensile strengths of the iron base alloys. The presence of hydrogen does not significantly contribute to strength degradation. Based percent highway driving cycle; CG-27 has adequate 3500 hr - 870 C creep rupture strength and SA-Fll, CRM-6D, and XF-818 have adequate 3500 hr - 775 C creep rupture strength.

  9. Prediction of hardness minimum locations during natural aging in an aluminum alloy 6061-T6 friction stir weld

    SciTech Connect

    Woo, Wan Chuck; Choo, Hahn; Feng, Zhili; Withers, Prof Philip

    2009-01-01

    This study describes a simple model that can predict the evolution of hardness distribution as a function of natural aging time in a heat-treatable 6061-T6 Al alloy plate subjected to friction stir welding (FSW). First, two dimensional thermal distributions were simulated as a function of time in the FSW plate by finite element modeling. Second, the hardness changes during natural aging were measured as a function of aging time for a number of Al specimens that had been previously isothermally heat-treated to different hold temperatures in order to determine the natural aging kinetics. Finally, the simulated temperature profiles and the natural aging kinetics were correlated to predict the hardness profiles in the FSW plate. The predicted hardness variations are consistent with measured hardness profiles in that the location of minimum hardness moves away from the centerline as the aging time and/or heat input increases. The hardness variation was also related to the location of failure in cross-weld tensile samples.

  10. Artificial Aging Effects on Cryogenic Fracture Toughness of the Main Structural Alloy for the Super Lightweight Tank

    NASA Technical Reports Server (NTRS)

    Chen, P. S.; Stanton, W. P.

    2002-01-01

    In 1996, Marshall Space Flight Center developed a multistep heating rate-controlled (MSRC) aging technique that significantly enhanced cryogenic fracture toughness (CFT) and reduced the statistical spread of fracture toughness values in alloy 2195 by controlling the location and size of strengthening precipitate T1. However, it could not be readily applied to flight-related hardware production, primarily because large-scale production furnaces are unable to maintain a heating rate of 0.6 C (1 F)/hr. In August 1996, a new program was initiated to determine whether the MSRC aging treatment could be further modified to facilitate its implementation to flight hardware production. It was successfully redesigned into a simplified two-step aging treatment consisting of 132 C (270 F)/20 hr + 138 C (280 F)/40 hr. Results indicated that two-step aging can achieve the same yield strength levels as those produced by conventional aging while providing greatly improved ductility. Two-step aging proved to be very effective at enhancing CFT, enabling previously rejected materials to meet simulated service requirements. Cryogenic properties are improved by controlling T1 nucleation and growth so that they are promoted in the matrix and suppressed in the subgrain boundaries.

  11. Assessment of retrogression and re-aging treatment on microstructural and mechanical properties of Al-Zn-Mg-Cu P/M alloy

    SciTech Connect

    Naeem, Haider T.; Mohammad, Kahtan S.; Hussin, Kamarudin; Tan, T. Qing; Idris, M. Sobri

    2015-05-15

    In order to understand the importance of the retrogression and re-aging as a heat treatment for improving microstructural and mechanical properties of the Al-Zn-Mg-Cu powder metallurgy alloys, Al-Zn-Mg-Cu-Fe-Cr alloys were fabricated from the elemental powders. Green compacts are compressed under compaction pressure about 370 MPa. The sintering process carried out for the samples of aluminum alloys at temperature was 650°C under argon atmosphere for two hours. The sintered compacts were subjected into homogenizing condition at 470°C for 1.5 hours and then aged at 120°C for 24 hours (T6 temper) after that it carried out the retrogressed at 180°C for 30 min., and then re-aged at 120°C for 24 hours (RRA). Observations microstructures were examined using optical, scanning electron microscopy coupled with energy dispersive spectroscopy and X-ray diffraction. Density and porosity content was conducted for the samples of alloys. The result showing that the highest Vickers hardness exhibited for an Al-Zn-Mg-Cu alloy after underwent the retrogression and reaging treatment. Increasing in hardness was because of the precipitation hardening through precipitate the (Mg Zn) and (Mg{sub 2}Zn{sub 11}) phases during matrix of aluminum-alloy.

  12. Assessment of retrogression and re-aging treatment on microstructural and mechanical properties of Al-Zn-Mg-Cu P/M alloy

    NASA Astrophysics Data System (ADS)

    Naeem, Haider T.; Mohammad, Kahtan S.; Hussin, Kamarudin; Tan, T. Qing; Idris, M. Sobri

    2015-05-01

    In order to understand the importance of the retrogression and re-aging as a heat treatment for improving microstructural and mechanical properties of the Al-Zn-Mg-Cu powder metallurgy alloys, Al-Zn-Mg-Cu-Fe-Cr alloys were fabricated from the elemental powders. Green compacts are compressed under compaction pressure about 370 MPa. The sintering process carried out for the samples of aluminum alloys at temperature was 650°C under argon atmosphere for two hours. The sintered compacts were subjected into homogenizing condition at 470°C for 1.5 hours and then aged at 120°C for 24 hours (T6 temper) after that it carried out the retrogressed at 180°C for 30 min., and then re-aged at 120°C for 24 hours (RRA). Observations microstructures were examined using optical, scanning electron microscopy coupled with energy dispersive spectroscopy and X-ray diffraction. Density and porosity content was conducted for the samples of alloys. The result showing that the highest Vickers hardness exhibited for an Al-Zn-Mg-Cu alloy after underwent the retrogression and reaging treatment. Increasing in hardness was because of the precipitation hardening through precipitate the (Mg Zn) and (Mg2Zn11) phases during matrix of aluminum-alloy.

  13. Method for dissolving plutonium dioxide

    DOEpatents

    Tallent, Othar K.

    1978-01-01

    The fluoride-catalyzed, non-oxidative dissolution of plutonium dioxide in HNO.sub.3 is significantly enhanced in rate by oxidizing dissolved plutonium ions. It is believed that the oxidation of dissolved plutonium releases fluoride ions from a soluble plutonium-fluoride complex for further catalytic action.

  14. Solid-liquid boundaries in iron-rich alloys and the age of the Earth's inner core

    NASA Astrophysics Data System (ADS)

    Li, J.; Chen, B.; Gao, L.

    2006-05-01

    Melting and solidification cause major chemical differentiation in the Earth. As the Earth cools, the liquid core solidifies from the center and the inner core grows at the expense of the outer core. The timing of the onset of core solidification remains poorly constrained. Labrosse et al. (2001) estimated the age of the Earth's inner core based on energy budget considerations. In their analysis, the latent heat and gravitational energy are calculated according to dislocation melting theory. We have conducted melting experiments on pure iron and an iron-sulfur alloy containing 15 at.% sulfur, in order to determine the effect of pressure on the Clapeyron slopes of the solid-liquid boundaries. Our results allow a critical examination of the energy estimates, hence the age of the inner core. The implications for the budget of radioactive elements will be discussed.

  15. Average Structure Evolution of δ-phase Pu-Ga Alloys

    SciTech Connect

    Smith, Alice Iulia; Page, Katharine L.; Gourdon, Olivier; Siewenie, Joan E.; Richmond, Scott; Saleh, Tarik A.; Ramos, Michael; Schwartz, Daniel S.

    2015-03-30

    [Full Text] Plutonium metal is a highly unusual element, exhibiting six allotropes at ambient pressure, from room temperature to its melting point. Many phases of plutonium metal are unstable with temperature, pressure, chemical additions, and time. This strongly affects structure and properties, and becomes of high importance, particularly when considering effects on structural integrity over long time periods. The fcc δ-phase deserves additional attention, not only in the context of understanding the electronic structure of Pu, but also as one of the few high-symmetry actinide phases that can be stabilized down to ambient pressure and room temperature by alloying it with trivalent elements. We will present results on recent work on aging of Pu-2at.%Ga and Pu-7at.%Ga alloys

  16. Plutonium Vulnerability Management Plan

    SciTech Connect

    1995-03-01

    This Plutonium Vulnerability Management Plan describes the Department of Energy`s response to the vulnerabilities identified in the Plutonium Working Group Report which are a result of the cessation of nuclear weapons production. The responses contained in this document are only part of an overall, coordinated approach designed to enable the Department to accelerate conversion of all nuclear materials, including plutonium, to forms suitable for safe, interim storage. The overall actions being taken are discussed in detail in the Department`s Implementation Plan in response to the Defense Nuclear Facilities Safety Board (DNFSB) Recommendation 94-1. This is included as Attachment B.

  17. Plutonium radiation surrogate

    DOEpatents

    Frank, Michael I.

    2010-02-02

    A self-contained source of gamma-ray and neutron radiation suitable for use as a radiation surrogate for weapons-grade plutonium is described. The source generates a radiation spectrum similar to that of weapons-grade plutonium at 5% energy resolution between 59 and 2614 keV, but contains no special nuclear material and emits little .alpha.-particle radiation. The weapons-grade plutonium radiation surrogate also emits neutrons having fluxes commensurate with the gamma-radiation intensities employed.

  18. Progress on plutonium stabilization

    SciTech Connect

    Hurt, D.

    1996-05-01

    The Defense Nuclear Facilities Safety Board has safety oversight responsibility for most of the facilities where unstable forms of plutonium are being processed and packaged for interim storage. The Board has issued recommendations on plutonium stabilization and has has a considerable influence on DOE`s stabilization schedules and priorities. The Board has not made any recommendations on long-term plutonium disposition, although it may get more involved in the future if DOE develops plans to use defense nuclear facilities for disposition activities.

  19. PLUTONIUM SEPARATION METHOD

    DOEpatents

    Beaufait, L.J. Jr.; Stevenson, F.R.; Rollefson, G.K.

    1958-11-18

    The recovery of plutonium ions from neutron irradiated uranium can be accomplished by bufferlng an aqueous solutlon of the irradiated materials containing tetravalent plutonium to a pH of 4 to 7, adding sufficient acetate to the solution to complex the uranyl present, adding ferric nitrate to form a colloid of ferric hydroxide, plutonlum, and associated fission products, removing and dissolving the colloid in aqueous nitric acid, oxldizlng the plutonium to the hexavalent state by adding permanganate or dichromate, treating the resultant solution with ferric nitrate to form a colloid of ferric hydroxide and associated fission products, and separating the colloid from the plutonlum left in solution.

  20. PLUTONIUM ELECTROREFINING CELLS

    DOEpatents

    Mullins, L.J. Jr.; Leary, J.A.; Bjorklund, C.W.; Maraman, W.J.

    1963-07-16

    Electrorefining cells for obtaining 99.98% plutonium are described. The cells consist of an impure liquid plutonium anode, a molten PuCl/sub 3/-- alkali or alkaline earth metal chloanode, a molten PuCl/sub 3/-alkali or alkaline earth metal chloride electrolyte, and a nonreactive cathode, all being contained in nonreactive ceramic containers which separate anode from cathode by a short distance and define a gap for the collection of the purified liquid plutonium deposited on the cathode. Important features of these cells are the addition of stirrer blades on the anode lead and a large cathode surface to insure a low current density. (AEC)

  1. Mechanisms of formation of hardening precipitates and hardening in aging of Al-Li-Cu-Mg model alloys with silver additions

    NASA Astrophysics Data System (ADS)

    Alekseev, A. A.; Zhuravleva, P. L.; Onuchina, M. R.; Klochkova, Yu. Yu.

    2015-11-01

    The mechanisms of the influence of silver additions on the phase transformations that occur in aging are revealed. The contribution of Ω'-phase particles to the deformation stress in Al alloys is estimated. The mechanisms of the effect of low (up to 0.5 wt %) silver additions and the copper content on the structure of the Ω'-phase precipitates in Al alloys are found. According to the proposed model, silver atoms remain immobile during the decomposition of a solid solution and nucleation centers of the Ω' phase form near them in low-temperature aging. Upon hardening aging, fragmented Ω'-phase particles intersect with each other, and the contribution of the intersection regions to the hardening of alloys by Ω'-phase particles is principal.

  2. Effect of high-temperature aging on electrical properties of HipercoxAE 27, HipercoxAE 50, and HipercoxAE 50 HS alloys

    NASA Astrophysics Data System (ADS)

    Geist, B.; Peterson, T.; Horwath, J. C.; Turgut, Z.; Huang, M. Q.; Snyder, R. A.; Fingers, R. T.

    2003-05-01

    Some more electric aircraft concepts require soft magnetic FeCo materials to be stable at temperatures as high as 773 K for long periods of time. At this high operating temperature, aging related processes may occur that result in changes in material properties. The material supplier typically specifies only room-temperature properties, and only limited reports are available on properties at elevated temperatures. The change in properties as a function of time at 773 K will give information on the lifetime of the material to assist designers when selecting materials for high-temperature applications. We have conducted a study on the effects of long-term aging on the magnetic, mechanical, and electrical properties of Hiperco® 27, Hiperco® 50, and Hiperco® 50 HS FeCo soft magnetic alloys. Samples of each material were aged in argon for 100, 1000, 2000, and 5000 h at 773 K. Here, we report the changes in electrical resistivity after aging. Of the three alloys, high-temperature aging has the greatest effect on the resistivity of Hiperco® 50. The electrical resistivities for each sample are compared and conclusions are drawn on the relative thermal stability of each alloy. The changes in electrical resistivities for each alloy are also related to changes in other properties, such as total power loss and coercivity, that were observed during this study on aging.

  3. Phase Transformation and Aging Behavior of Al0.5CoCrFeNiSi0.2 High-Entropy Alloy

    NASA Astrophysics Data System (ADS)

    Zhang, C.; Wu, G. F.; Dai, P. Q.

    2015-05-01

    An Al0.5CoCrFeNiSi0.2 high-entropy alloy was prepared by vacuum arc melting. The alloy was aged from 700 to 1100 °C. The effects of aging on the phase transformation and mechanical performances were explored. The as-cast alloy showed a dendritic (DR) microstructure. The DR region was an Fe,Cr-rich FCC phase, while the interdendritic (ID) region was a spinodal structure composed of Fe,Cr-rich BCC (A2) and Ni,Al-rich BCC (B2) phases. At aging temperatures between 700 and 900 °C, the Fe,Cr-rich BCC (A2) phase in the ID region transformed into σ and Fe,Cr-rich FCC phases. Meanwhile, some Ni,Al-rich FCC phase particles precipitated from the DR region. During aging at 1100 °C, the DR microstructure disappeared, and a microstructure composed of Fe,Cr-rich FCC and Ni,Al-rich BCC (B2) phases both possessing a lamellar shape was developed. The alloy exhibited evident hardening and lower tensile strain when the aging temperature was lower than 1000 °C, which was mainly attributed to the generation of the σ phase in the ID region. However, a contrasting behavior was observed when the aging temperature was higher than 1000 °C, which was attributed to the redissolution of the σ phase and the microstructure coarsening.

  4. Capillarity Effect Controlled Precipitate Growth at the Grain Boundary of Long-Term Aging Al 5083 Alloy

    NASA Astrophysics Data System (ADS)

    Yi, Gaosong; Free, Michael L.; Zhu, Yakun; Derrick, Alexander T.

    2014-10-01

    A model was developed to predict thickness and continuity of β phase (Al3Mg2) formed at grain boundaries of long-term aged Al 5083 alloy. In this model, a variable collector plate mechanism was adopted at the early stage of aging, then, at about 1 month (), the model transitions to a constant collector plate mechanism. Two concentration profiles of Mg, one for a semi-infinite bulk at short diffusion distances and one for a finite slab at long diffusion distances ( of the grain size), were applied to this model for different aging times. Capillarity effects were used to determine the morphology of β phase at the grain boundary. Combining different collector plate mechanisms and Mg concentration profiles, the whole β phase growth process was divided into three stages (short-term Mg concentration profile-variable collector plate, short-term Mg concentration profile-constant collector plate, and long-term Mg concentration profile-constant collector plate). Finally, the model was solved numerically. Experimental results of β phase length and thickness were obtained using transmission electron microscopy (TEM) images of Al 5083 aged at 343 K (70 °C) for different thermal exposure times. Modeling results of β phase thickness and continuity agree well with experimental observations.

  5. Plutonium dissolution process

    DOEpatents

    Vest, Michael A.; Fink, Samuel D.; Karraker, David G.; Moore, Edwin N.; Holcomb, H. Perry

    1996-01-01

    A two-step process for dissolving plutonium metal, which two steps can be carried out sequentially or simultaneously. Plutonium metal is exposed to a first mixture containing approximately 1.0M-1.67M sulfamic acid and 0.0025M-0.1M fluoride, the mixture having been heated to a temperature between 45.degree. C. and 70.degree. C. The mixture will dissolve a first portion of the plutonium metal but leave a portion of the plutonium in an oxide residue. Then, a mineral acid and additional fluoride are added to dissolve the residue. Alteratively, nitric acid in a concentration between approximately 0.05M and 0.067M is added to the first mixture to dissolve the residue as it is produced. Hydrogen released during the dissolution process is diluted with nitrogen.

  6. Plutonium: Requiem or reprieve

    SciTech Connect

    Pillay, K.K.S.

    1996-01-01

    Many scientific discoveries have had profound effects on humanity and its future. However, the discovery of fissionable characteristics of a man-made element, plutonium, discovered in 1941 by Glenn Seaborg and associates, has probably had the greatest impact on world affairs. Although about 20 new elements have been synthesized since 1940, element 94 unarguably had the most dramatic impact when it was introduced to the world as the core of the nuclear bomb dropped on Nagasaki. Ever since, large quantities of this element have been produced, and it has had a major role in maintaining peace during the past 50 years. in addition, the rapid spread of nuclear power technology worldwide contributed to major growth in the production of plutonium as a by-product. This article discusses the following issues related to plutonium: plutonium from Nuclear Power Generation; environmental safety and health issues; health effects; safeguards issues; extended storage; disposal options.

  7. Thermal aging effects on the microstructure, oxidation behavior, and mechanical properties of as-cast nickel aluminide alloys

    NASA Astrophysics Data System (ADS)

    Lee, Dongyun

    The thermal aging effects on the microstructure, oxidation behavior at 900° and 1100°C, and mechanical properties of IC221M (Ni3Al based intermetallic alloy, ASTM A1002-99) were investigated. The microstructure consists of dendritic arms of the gamma (nickel solid solution) phase containing cube-shape gamma' (Ni3Al precipitates. The interdendritic regions are mostly gamma' (Ni3Al with up to 8 vol.% gamma + Ni5Zr eutectic constituents. Thermal aging effects on the microstructures and how microsegregation affects the oxidation behavior were examined. Four primary changes in the microstructures were observed: (1) there is considerable homogenization of the cast microstructures with aging, (2) the volume fraction of gamma' increases with aging time and temperature, (3) the gamma' phase coarsens, and (4) the volume fraction of the gamma + Ni5Zr eutectic constituents decreases. During the initial stages of oxidation at 900°C, surface oxides form along the microsegregation patterns, revealing the cast microstructures. The first oxide to form is mostly NiO with small amounts of Cr2O 3, ZrO2, NiCr2O4, and theta-Al 2O3. Initial oxidation occurs primarily in the interdendritic regions due to microsegregation of alloying elements during casting. With further aging, the predominant surface oxides become NiO and NiAl2O 4 spinel, with a continuous film of alpha-Al2O3 forming immediately beneath them. Although these oxides are constrained to the near surface region, other oxides penetrate to greater depths, facilitated by oxidation of the gamma + Ni5Zr eutectic constituents. These oxides appear in the microstructure as long, thin spikes of ZrO2 surrounded by a sheath of Al2O3. They can penetrate to depths greater than 10 times that of the continuous surface oxide. The oxidation behavior at 1100°C is similar to that at 900°C, but the oxidation kinetics are faster, NiO dominates at all aging periods, and the surface oxides do not adhere to the matrix meaning that a protective

  8. Structure and mechanical properties of aging Al-Li-Cu-Zr-Sc-Ag alloy after severe plastic deformation by high-pressure torsion

    NASA Astrophysics Data System (ADS)

    Kaigorodova, L. I.; Rasposienko, D. Yu.; Pushin, V. G.; Pilyugin, V. P.; Smirnov, S. V.

    2015-04-01

    The structural and phase transformations have been studied in aging commercial aluminum-lithium alloy Al-1.2 Li-3.2 Cu-0.09 Zr-0.11 Sc-0.4 Ag-0.3 Mg in the as-delivered state and after severe plastic deformation by torsion for 1, 5 and 10 revolutions under a high pressure of 4 GPa. Deformation-induced nanofragmentation and dynamic recrystallization have been found to occur in the alloy. The degree of recrystallization increases with deformation. Nanofragmentation and recrystallization processes are accompanied by the deformation-induced decomposition of solid solution and changes in both the nucleation mechanism of precipitation and the phase composition of the alloy. The influence of a nanostructured nanophase state of the alloy on its mechanical properties (microhardness, plasticity, elastic modulus, and stiffness) is discussed.

  9. Improved Stress Corrosion Cracking Resistance and Strength of a Two-Step Aged Al-Zn-Mg-Cu Alloy Using Taguchi Method

    NASA Astrophysics Data System (ADS)

    Lin, Lianghua; Liu, Zhiyi; Ying, Puyou; Liu, Meng

    2015-12-01

    Multi-step heat treatment effectively enhances the stress corrosion cracking (SCC) resistance but usually degrades the mechanical properties of Al-Zn-Mg-Cu alloys. With the aim to enhance SCC resistance as well as strength of Al-Zn-Mg-Cu alloys, we have optimized the process parameters during two-step aging of Al-6.1Zn-2.8Mg-1.9Cu alloy by Taguchi's L9 orthogonal array. In this work, analysis of variance (ANOVA) was performed to find out the significant heat treatment parameters. The slow strain rate testing combined with scanning electron microscope and transmission electron microscope was employed to study the SCC behaviors of Al-Zn-Mg-Cu alloy. Results showed that the contour map produced by ANOVA offered a reliable reference for selection of optimum heat treatment parameters. By using this method, a desired combination of mechanical performances and SCC resistance was obtained.

  10. Evolution of the microstructure and hardness of a rapidly solidified/melt-spun AZ91 alloy upon aging at different temperatures

    SciTech Connect

    Wang Baishu; Liu Yongbing; An Jian; Li Rongguang; Su Zhenguo; Su Guihua; Lu You; Cao Zhanyi

    2009-04-15

    The effect of aging at different temperatures on a rapidly solidified/melt-spun AZ91 alloy has been investigated in depth. The microstructures of as-spun and aged ribbons with a thickness of approximately 60 {mu}m were characterized using X-ray diffraction, transmission electron microscopy and laser optical microscopy; microhardness measurements were also conducted. It was found that the commercial AZ91 alloy undergoes a cellular/dendritic transition during melt-spinning at a speed of 34 m/s. A strengthening effect due to aging was observed: a maximum hardness of 110 HV/0.05 and an age-hardenability of 50% were obtained when the ribbon was aged at 200 deg. C for 20 min. The {beta}-Mg{sub 17}Al{sub 12} phase exhibits net and dispersion types of distribution during precipitation. The dispersion of precipitates in dendritic grains or cells is the main source of strengthening.

  11. Natural aging and reversion behavior of Al-Cu-Li-Ag-Mg alloy Weldalite (tm) 049

    NASA Technical Reports Server (NTRS)

    Gayle, Frank W.; Heubaum, Frank H.; Pickens, Joseph R.

    1991-01-01

    This study was initiated to understand the natural aging and reversion behavior of Weldalite (trademark) 049 in tempers without cold work. Of particular interest are: (1) the microstructural basis for the high strength in the T4 condition; (2) an explanation of the reversion phenomenon; and (3) the effect of re-aging at room temperature after a reversion treatment. Mechanical properties were measured and transmission electron microscopy (TEM) analysis performed at various stages of microstructural development during aging, reversion, and subsequent re-aging.

  12. Dissolution of plutonium metal in HNO/sub 3/-N/sub 2/H/sub 4/-KF

    SciTech Connect

    Karraker, D G

    1983-07-01

    Plutonium metal dissolves in HNO/sub 3/-N/sub 2/H/sub 4/.HNO/sub 3/-KF solution to yield a Pu/sup 3 +/ solution without an accompanying precipitation of plutonium oxide solids. The reaction evolves less than 0.2 mole of gas per mole of plutonium dissolved; the gas contains only 3% H/sub 2/. About 10/sup -3/ moles of HN/sub 3/ are produced per mole of plutonium dissolved. Optimum conditions for dissolving both alpha-phase and delta-phase plutonium metal were developed. Possible applications are to the recovery of plutonium metal or the processing of irradiated plutonium metal and alloys.

  13. Elemental composition in sealed plutonium-beryllium neutron sources.

    PubMed

    Xu, N; Kuhn, K; Gallimore, D; Martinez, A; Schappert, M; Montoya, D; Lujan, E; Garduno, K; Tandon, L

    2014-10-22

    Five sealed plutonium-beryllium (PuBe) neutron sources from various manufacturers were disassembled. Destructive chemical analyses for recovered PuBe materials were conducted for disposition purposes. A dissolution method for PuBe alloys was developed for quantitative plutonium (Pu) and beryllium (Be) assay. Quantitation of Be and trace elements was performed using plasma based spectroscopic instruments, namely inductively coupled plasma mass spectrometry (ICP-MS) and atomic emission spectrometry (ICP-AES). Pu assay was accomplished by an electrochemical method. Variations in trace elemental contents among the five PuBe sources are discussed. PMID:25464182

  14. Plutonium disproportionation: the ambiguity phenomenon.

    PubMed

    Silver, G L

    2003-05-01

    Plutonium oxidation-state studies may yield ambiguous results if the parameters are not carefully chosen. The effect can be related to environmental plutonium as illustrated by an example. PMID:12735968

  15. INTERCOMPARISON OF PLUTONIUM-239 MEASUREMENTS

    EPA Science Inventory

    In 1977 the U.S. Environmental Protection Agency distributed calibrated solutions of plutonium-239 to laboratories interested in participating in an intercomparison study of plutonium analysis. Participants were asked to perform a quantitative radioactivity analysis of the soluti...

  16. METHOD OF MAKING PLUTONIUM DIOXIDE

    DOEpatents

    Garner, C.S.

    1959-01-13

    A process is presented For converting both trivalent and tetravalent plutonium oxalate to substantially pure plutonium dioxide. The plutonium oxalate is carefully dried in the temperature range of 130 to300DEC by raising the temperature gnadually throughout this range. The temperature is then raised to 600 C in the period of about 0.3 of an hour and held at this level for about the same length of time to obtain the plutonium dioxide.

  17. METHOD OF PRODUCING PLUTONIUM TETRAFLUORIDE

    DOEpatents

    Tolley, W.B.; Smith, R.C.

    1959-12-15

    A process is presented for preparing plutonium tetrafluoride from plutonium(IV) oxalate. The oxalate is dried and decomposed at about 300 deg C to the dioxide, mixed with ammonium bifluoride, and the mixture is heated to between 50 and 150 deg C whereby ammonium plutonium fluoride is formed. The ammonium plutonium fluoride is then heated to about 300 deg C for volatilization of ammonium fluoride. Both heating steps are preferably carried out in an inert atmosphere.

  18. Ageing characteristics of the metastable gamma phase in U-9 wt.% Mo alloy: experimental observations and thermodynamic validation

    NASA Astrophysics Data System (ADS)

    Neogy, S.; Saify, M. T.; Jha, S. K.; Srivastava, D.; Dey, G. K.

    2015-09-01

    Ageing characteristics of the metastable bcc γ-phase in U-9 wt.% Mo alloy, a candidate for high uranium density nuclear fuel for research and test reactors, have been investigated in this study. Analyses of the aged microstructures, employing X-ray diffraction and various microscopy techniques, revealed the decomposition mechanism of the metastable γ-phase to the stable α-U and γ‧ (U2Mo) phases. A discontinuous precipitation reaction, leading to the generation of partially transformed cellular colonies with lamellae comprising of either the α-phase or the γ‧-phase in γ-phase matrix, was found to be operative. The in situ transformation of γ interlamellar regions to the γ‧-phase was noticed occasionally within the γ + α lamellar colonies. Thermodynamic analysis of the U-Mo system, using free energy-composition diagrams, could associate the observed attributes of the decomposition of γ-phase to the extent of Mo segregation and the chemical driving force required for the nucleation of α- and γ‧-phases in the γ-matrix.

  19. Plutonium 239 Equivalency Calculations

    SciTech Connect

    Wen, J

    2011-05-31

    This document provides the basis for converting actual weapons grade plutonium mass to a plutonium equivalency (PuE) mass of Plutonium 239. The conversion can be accomplished by performing calculations utilizing either: (1) Isotopic conversions factors (CF{sub isotope}), or (2) 30-year-old weapons grade conversion factor (CF{sub 30 yr}) Both of these methods are provided in this document. Material mass and isotopic data are needed to calculate PuE using the isotopic conversion factors, which will provide the actual PuE value at the time of calculation. PuE is the summation of the isotopic masses times their associated isotopic conversion factors for plutonium 239. Isotopic conversion factors are calculated by a normalized equation, relative to Plutonium 239, of specific activity (SA) and cumulated dose inhalation affects based on 50-yr committed effective dose equivalent (CEDE). The isotopic conversion factors for converting weapons grade plutonium to PuE are provided in Table-1. The unit for specific activity (SA) is curies per gram (Ci/g) and the isotopic SA values come from reference [1]. The cumulated dose inhalation effect values in units of rem/Ci are based on 50-yr committed effective dose equivalent (CEDE). A person irradiated by gamma radiation outside the body will receive a dose only during the period of irradiation. However, following an intake by inhalation, some radionuclides persist in the body and irradiate the various tissues for many years. There are three groups CEDE data representing lengths of time of 0.5 (D), 50 (W) and 500 (Y) days, which are in reference [2]. The CEDE values in the (W) group demonstrates the highest dose equivalent value; therefore they are used for the calculation.

  20. Lithium metal reduction of plutonium oxide to produce plutonium metal

    DOEpatents

    Coops, Melvin S.

    1992-01-01

    A method is described for the chemical reduction of plutonium oxides to plutonium metal by the use of pure lithium metal. Lithium metal is used to reduce plutonium oxide to alpha plutonium metal (alpha-Pu). The lithium oxide by-product is reclaimed by sublimation and converted to the chloride salt, and after electrolysis, is removed as lithium metal. Zinc may be used as a solvent metal to improve thermodynamics of the reduction reaction at lower temperatures. Lithium metal reduction enables plutonium oxide reduction without the production of huge quantities of CaO--CaCl.sub.2 residues normally produced in conventional direct oxide reduction processes.

  1. Interfacial Reactions of Zn-Al Alloys with Na Addition on Cu Substrate During Spreading Test and After Aging Treatments

    NASA Astrophysics Data System (ADS)

    Gancarz, Tomasz; Pstruś, Janusz; Berent, Katarzyna

    2016-04-01

    Spreading tests for Cu substrate with Zn-Al eutectic-based alloys with 0.2, 0.5, and 1.0 wt.% of Na were studied using the sessile drop method in the presence of QJ201 flux. Spreading tests were performed for 1, 3, 8, 15, 30, and 60 min of contact, at the temperatures of 475, 500, 525, and 550 °C. After cleaning the flux residue from solidified samples, the spreading area of Zn-Al + Na on Cu was determined in accordance with ISO 9455-10:2013-03. Selected, solidified solder-substrate couples were cross-sectioned and subjected to scanning electron microscopy of the interfacial microstructure. The experiment was designed to demonstrate the effect of Na addition on the kinetics of formation and growth of CuZn, Cu5Zn8, and CuZn4 phases, which were identified using x-ray diffraction and energy-dispersive spectroscopy analysis. The addition of Na to eutectic Zn-Al caused the spreading area to decrease and the thickness of intermetallic compound layers at the interface to reduce. Samples after the spreading test at 500 °C for 1 min were subjected to aging for 1, 10, and 30 days at 120,170, and 250 °C. The greater thicknesses of IMC layers were obtained for a temperature of 250 °C. With increasing Na content in Zn-Al + Na alloys, the thickness reduced, which correlates to the highest value of activation energy for Zn-Al with 1% Na.

  2. Phase state of a Bi-43 wt % Sn superplastic alloy and its changes under the effect of external mechanical stresses and aging

    NASA Astrophysics Data System (ADS)

    Korshak, V. F.; Chushkina, R. A.; Shapovalov, Yu. A.; Mateichenko, P. V.

    2011-07-01

    Samples of a Bi-43 wt % Sn superplastic alloy have been studied by X-ray diffraction in the ascast state, after compression of as-cast samples to ˜70% on a hydraulic press, after aging in the as-cast and preliminarily compressed state, and using samples deformed under superplastic conditions. The X-ray diffraction studies have been carried out using a DRON-2.0 diffractometer in Cu Kα radiation. The samples aged and deformed under superplasticity conditions have been studied using electron-microprobe analysis in a JSM-820 scanning electron microscope equipped with a LINK AN/85S EDX system. It has been found that the initial structural-phase state of the alloy was amorphous-crystalline. Causes that lead to a change in this state upon deformation and aging are discussed. A conclusion is made that the superplasticity effect manifests itself against the background of processes that are stipulated by the tendency of the initially metastable alloy to phase equilibrium similarly to what is observed in the Sn-38 wt % Pb eutectic alloy studied earlier.

  3. Nonequilibrium grain-boundary segregation and ductile-brittle-ductile transition in Fe-Mn-Ni-Ti age-hardening alloy

    SciTech Connect

    Heo, N.H.

    1996-10-01

    Nonequilibrium segregation kinetics of alloying elements and a ductile-brittle-ductile transition behavior have been investigated in an Fe-8.4Mn-7.4Ni-1.7Ti alloy. The alloy experienced a ductile-brittle-ductile (DBD) transition during isothermal aging. In the brittle region, the alloy showed a decrease in intergranular fracture strength and a subsequent increase with aging time. This is due to the segregation of titanium to the grain boundaries and its desegregation into the matrix. The intergranular fracture strength was higher on the zero tensile elongation finish curve than on the start curve. This is because the grain-boundary segregation level of titanium is relatively lower on the finish curve. The lowest intergranular fracture strength increased with increasing aging temperature, which was attributed to a lower grain-boundary segregation level of titanium at higher temperature. Manganese caused an overall reduction in intergranular fracture strength and, as a result, the delayed occurrence of the zero tensile elongation (ZTE) finish curve in a temperature and long-time plot.

  4. Plutonium in Concentrated Solutions

    SciTech Connect

    Clark, Sue B.; Delegard, Calvin H.

    2002-08-01

    Complex, high ionic strength media are used throughout the plutonium cycle, from its processing and purification in nitric acid, to waste storage and processing in alkaline solutions of concentrated electrolytes, to geologic disposal in brines. Plutonium oxidation/reduction, stability, radiolysis, solution and solid phase chemistry have been studied in such systems. In some cases, predictive models for describing Pu chemistry under such non-ideal conditions have been developed, which are usually based on empirical databases describing specific ion interactions. In Chapter 11, Non-Ideal Systems, studies on the behavior of Pu in various complex media and available model descriptions are reviewed.

  5. SULFIDE METHOD PLUTONIUM SEPARATION

    DOEpatents

    Duffield, R.B.

    1958-08-12

    A process is described for the recovery of plutonium from neutron irradiated uranium solutions. Such a solution is first treated with a soluble sullide, causing precipitation of the plutoniunn and uraniunn values present, along with those impurities which form insoluble sulfides. The precipitate is then treated with a solution of carbonate ions, which will dissolve the uranium and plutonium present while the fission product sulfides remain unaffected. After separation from the residue, this solution may then be treated by any of the usual methods, such as formation of a lanthanum fluoride precipitate, to effect separation of plutoniunn from uranium.

  6. Fabrication of anti-aging TiO2 nanotubes on biomedical Ti alloys.

    PubMed

    Hamlekhan, Azhang; Butt, Arman; Patel, Sweetu; Royhman, Dmitry; Takoudis, Christos; Sukotjo, Cortino; Yuan, Judy; Jursich, Gregory; Mathew, Mathew T; Hendrickson, William; Virdi, Amarjit; Shokuhfar, Tolou

    2014-01-01

    The primary objective of this study was to fabricate a TiO2 nanotubular surface, which could maintain hydrophilicity over time (resist aging). In order to achieve non-aging hydrophilic surfaces, anodization and annealing conditions were optimized. This is the first study to show that anodization and annealing condition affect the stability of surface hydrophilicity. Our results indicate that maintenance of hydrophilicity of the obtained TiO2 nanotubes was affected by anodization voltage and annealing temperature. Annealing sharply decreased the water contact angle (WCA) of the as-synthesized TiO2 nanotubular surface, which was correlated to improved hydrophilicity. TiO2 nanotubular surfaces are transformed to hydrophilic surfaces after annealing, regardless of annealing and anodization conditions; however, WCA measurements during aging demonstrate that surface hydrophilicity of non-anodized and 20 V anodized samples decreased after only 11 days of aging, while the 60 V anodized samples maintained their hydrophilicity over the same time period. The nanotubes obtained by 60 V anodization followed by 600 °C annealing maintained their hydrophilicity significantly longer than nanotubes which were obtained by 60 V anodization followed by 300 °C annealing. PMID:24788345

  7. Fabrication of Anti-Aging TiO2 Nanotubes on Biomedical Ti Alloys

    PubMed Central

    Hamlekhan, Azhang; Butt, Arman; Patel, Sweetu; Royhman, Dmitry; Takoudis, Christos; Sukotjo, Cortino; Yuan, Judy; Jursich, Gregory; Mathew, Mathew T.; Hendrickson, William; Virdi, Amarjit; Shokuhfar, Tolou

    2014-01-01

    The primary objective of this study was to fabricate a TiO2 nanotubular surface, which could maintain hydrophilicity over time (resist aging). In order to achieve non-aging hydrophilic surfaces, anodization and annealing conditions were optimized. This is the first study to show that anodization and annealing condition affect the stability of surface hydrophilicity. Our results indicate that maintenance of hydrophilicity of the obtained TiO2 nanotubes was affected by anodization voltage and annealing temperature. Annealing sharply decreased the water contact angle (WCA) of the as-synthesized TiO2 nanotubular surface, which was correlated to improved hydrophilicity. TiO2 nanotubular surfaces are transformed to hydrophilic surfaces after annealing, regardless of annealing and anodization conditions; however, WCA measurements during aging demonstrate that surface hydrophilicity of non-anodized and 20 V anodized samples decreased after only 11 days of aging, while the 60 V anodized samples maintained their hydrophilicity over the same time period. The nanotubes obtained by 60 V anodization followed by 600 °C annealing maintained their hydrophilicity significantly longer than nanotubes which were obtained by 60 V anodization followed by 300 °C annealing. PMID:24788345

  8. ALLOY FOR FUEL OF NEUTRONIC REACTORS

    DOEpatents

    Bloomster, C.H.; Katayama, Y.B.

    1963-04-23

    This patent deals with an aluminum alloy suitable as nuclear fuel and consisting mainly of from 1 to 10 wt% of plutonium, from 2 to 3.5 wt% of nickel, the balance being aluminum. The alloy may also contain from 0.9 to 1.1 wt% of silicon and up to 0.7% of iron. (AEC)

  9. Damage Assessment of Creep Tested and Thermally Aged Metallic Alloys Using Acousto-Ultrasonics

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, Andrew L.; Kautz, Harold E.; Baaklini, George Y.

    2001-01-01

    In recent years emphasis has been placed on the early detection of material changes experienced in turbine powerplant components. During the scheduled overhaul of a turbine, the current techniques of examination of various hot section components aim to find flaws such as cracks, wear, and erosion, as well as excessive deformations. Thus far, these localized damage modes have been detected with satisfactory results. However, the techniques used to find these flaws provide no information on life until the flaws are actually detected. Major improvements in damage assessment, safety, as well as more accurate life prediction could be achieved if nondestructive evaluation (NDE) techniques could be utilized to sense material changes that occur prior to the localized defects mentioned. Because of elevated temperatures and excessive stresses, turbine components may experience creep behavior. As a result, it is desirable to monitor and access the current condition of such components. Research at the NASA Glenn Research Center involves developing and utilizing an NDE technique that discloses distributed material changes that occur prior to the localized damage detected by the current methods of inspection. In a recent study, creep processes in a nickel-base alloy were the life-limiting condition of interest, and the NDE technique was acousto-ultrasonics (AU). AU is an NDE technique that utilizes two ultrasonic transducers to interrogate the condition of a test specimen. The sending transducer introduces an ultrasonic pulse at a point on the surface of the specimen while a receiving transducer detects the signal after it has passed through the material. The goal of the method is to correlate certain parameters of the detected waveform to characteristics of the material between the two transducers. Here, the waveform parameter of interest is the attenuation due to internal damping for which information is being garnered from the frequency domain. The parameters utilized to

  10. Plutonium: An introduction

    SciTech Connect

    Condit, R.H.

    1993-10-01

    This report is a summary of the history and properties of plutonium. It presents information on the atoms, comparing chemical and nuclear properties. It looks at the history of the atom, including its discovery and production methods. It summarizes the metallurgy and chemistry of the element. It also describes means of detecting and measuring the presence and quantity of the element.

  11. Techniques for lithium removal from 1040 C aged tantalum alloy, T-111

    NASA Technical Reports Server (NTRS)

    Gahn, R. F.

    1973-01-01

    The liquid ammonia and vacuum distillation techniques were found to be satisfactory for removing lithium from 1040 C aged T-111 (tantalum - 8-percent tungsten- 2-percent hafnium). Results of ductility tests and chemical analysis show that these two methods are adequate for removing lithium without embrittlement or contamination of the T-111. Moist air exposure of T-111 with traces of lithium on the surface produced mixed results. Some specimens were ductile; others were brittle. Brittle T-111 had an increased hydrogen content. Water removal of lithium from T-111 caused brittleness and an increased hydrogen concentration.

  12. Glovebox enclosed dc plasma source for the determination of metals in plutonium

    SciTech Connect

    Morris, W.F.

    1986-01-15

    The direct current plasma source of a Beckman Spectraspan IIIB emission spectrometer was enclosed in a glovebox at Lawrence Livermore National Laboratory in December 1982. Since that time, the system has been used for the routine determination of alloy and impurity metals in plutonium. This paper presents the systematic steps involved in developing the glovebox and gives information regarding performance of the plasma in the glovebox and the effectiveness of containment of plutonium. 8 refs., 9 figs., 3 tabs.

  13. The Influence of Ni and V Trace Elements on High-Temperature Tensile Properties and Aging of A356 Aluminum Foundry Alloy

    NASA Astrophysics Data System (ADS)

    di Giovanni, Maria Teresa; Cerri, Emanuela; Casari, Daniele; Merlin, Mattia; Arnberg, Lars; Garagnani, Gian Luca

    2016-05-01

    High-temperature tensile properties of unmodified A356 alloy with and without the addition of Ni or V in traces (600 and 1000 ppm of Ni and V, respectively) were investigated by analyzing samples obtained from sand and permanent mold castings in the as-cast and T6 heat-treated conditions. Tensile tests were performed at 508 K (235 °C) at a crosshead speed of 1 mm/min. In addition, samples were subjected to artificial aging at 508 K (235 °C) for different times, and corresponding hardness curves were plotted. Microstructures and fracture surfaces, analyzed by FEG-SEM equipped with energy dispersive X-ray spectroscopy, showed that neither Ni nor V addition had a detrimental effect on high-temperature tensile properties. Aging curves showed a strong loss of hardness affecting the T6 class between 30-min and 1-h exposure time. After 6-h aging, no evidence of aging treatment persisted on hardness of the tested material. Hardness values did not reveal any significant difference between the reference alloy and the Ni- and V-containing alloys in both casting conditions, in complete analogy with the tensile properties. Unmodified eutectic silicon particles provided inhomogeneity in the α-Al matrix and acted as the principal source of stress concentration leading to fracture.

  14. SCC INITIATION AND GROWTH RATE STUDIES ON TITANIUM GRADE 7 AND BASE METAL, WELDED, AND AGED ALLOY 22 IN CONCENTRATED GROUNDWATER

    SciTech Connect

    J.H. Payer

    2005-08-01

    The stress corrosion crack initiation and growth rate response was evaluated on as-received, as-welded, cold worked and aged Alloy 22 (UNS N06022) and titanium Grades 7 (UNS R52400), 28 (UNS R55323) and 29 (UNS R56404) at 105-165 C in various aerated, concentrated groundwater environments. Time-to-failure experiments on actively-loaded tensile specimens at 105 C evaluated the effects of applied stress, welding, surface finish, shot peening, cold work, crevicing, and aging treatments in Alloy 22 (UNS N06022), and found these materials to be highly resistant to SCC (none observed). Long-term U-bend data at 165 C corroborated these findings. Titanium Grade 7 and stainless steels were also included in the 105 C test matrix. Long term crack growth rate data showed stable crack growth in titanium Grade 7. Recent creep tests in air confirm literature data that these alloys are quite susceptible to creep failure, even below the yield stress, and it is unclear whether cracking in SCC tests is only accelerated by the creep response, or whether creep is responsible for cracking. Alloy 22 exhibited stable growth rates under ''gentle'' cyclic loading, but was prone to crack arrest at fully static loading. No effect of Pb additions was observed.

  15. Liquid-metal embrittlement of refractory metals by molten plutonium

    SciTech Connect

    Lesuer, D.R.; Bergin, J.B.; McInturff, S.A.; Kuhn, B.A.

    1980-07-01

    Embrittlement by molten plutonium of the refractory metals and alloys W-25 wt % Re, tantalum, molybdenum, and Ta-10 wt % W was studied. At 900/sup 0/C and a strain rate of 10/sup -4/ s/sup -1/, the materials tested may be ranked in order of decreasing susceptibility to liquid-plutonium embrittlement as follows: molybdenum, W-25 wt % Re, Ta-10 wt % W, and tantalum. These materials exhibited a wide range in susceptibility. Embrittlement was found to exhibit a high degree of temperature and strain-rate dependence, and we present arguments that strongly support a stress-assisted, intergranular, liquid-metal corrosion mechanism. We also believe microstructure plays a key role in the extent of embrittlement. In the case of W-25 wt % Re, we have determined that a dealloying corrosion takes place in which rhenium is selectively withdrawn from the alloy.

  16. Plutonium Finishing Plant. Interim plutonium stabilization engineering study

    SciTech Connect

    Sevigny, G.J.; Gallucci, R.H.; Garrett, S.M.K.; Geeting, J.G.H.; Goheen, R.S.; Molton, P.M.; Templeton, K.J.; Villegas, A.J.; Nass, R.

    1995-08-01

    This report provides the results of an engineering study that evaluated the available technologies for stabilizing the plutonium stored at the Plutonium Finishing Plant located at the hanford Site in southeastern Washington. Further processing of the plutonium may be required to prepare the plutonium for interim (<50 years) storage. Specifically this document provides the current plutonium inventory and characterization, the initial screening process, and the process descriptions and flowsheets of the technologies that passed the initial screening. The conclusions and recommendations also are provided. The information contained in this report will be used to assist in the preparation of the environmental impact statement and to help decision makers determine which is the preferred technology to process the plutonium for interim storage.

  17. PREPARATION OF ACTINIDE-ALUMINUM ALLOYS

    DOEpatents

    Moore, R.H.

    1962-09-01

    BS>A process is given for preparing alloys of aluminum with plutonium, uranium, and/or thorium by chlorinating actinide oxide dissolved in molten alkali metal chloride with hydrochloric acid, chlorine, and/or phosgene, adding aluminum metal, and passing air and/or water vapor through the mass. Actinide metal is formed and alloyed with the aluminum. After cooling to solidification, the alloy is separated from the salt. (AEC)

  18. 4. VIEW OF PLUTONIUM CANISTER ON CHAINVEYOR. SCRAP PLUTONIUM WAS ...

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

    4. VIEW OF PLUTONIUM CANISTER ON CHAINVEYOR. SCRAP PLUTONIUM WAS COLLECTED INTO CANS AT INDIVIDUAL WORKSTATIONS. THE CANS WERE TRANSFERRED VIA THE CHAIN CONVEYOR TO A WORKSTATION IN MODULE C WHERE THE MATERIAL WAS COMPRESSED INTO BRIQUETTES FOR LATER USE. (6/20/93) - Rocky Flats Plant, Plutonium Manufacturing Facility, North-central section of Plant, just south of Building 776/777, Golden, Jefferson County, CO

  19. Effect of Aging Treatment on Superelasticity of a Ti48.8Ni50.8V0.4 Alloy

    NASA Astrophysics Data System (ADS)

    Zhao, H.; Liang, C. Q.; Liu, J. T.; Tong, Y. X.; Chen, F.; Tian, B.; Li, L.; Zheng, Y. F.

    2012-12-01

    In this study, effect of aging treatment on microstructure, deformation behavior, and superelasticity of Ti48.8Ni50.8V0.4 alloy was investigated. After aging at 400 °C for 30 min, Ti3Ni4 precipitates formed. With increasing aging temperature from 300 to 450 °C, the yield strength of reoriented martensite increased due to the strengthening effect of Ti3Ni4 phase, thus improved the shape recovery ratio and reduced the stress hysteresis. Further increasing the aging temperature, the size of Ti3Ni4 precipitates increased and the coherency between precipitate and matrix gradually lost, leading to the decreasing yield strength of reoriented martensite and shape recovery ratio. Simultaneously, the stress hysteresis increased resulting from the hinder of plastic deformation to the interfacial movement during phase transformation. The critical stress to induce martensitic transformation continuously decreased with increasing aging temperature.

  20. Surprising Coordination for Plutonium in the First Plutonium (III) Borate

    SciTech Connect

    Wang, Shuao; Alekseev, Evgeny V.; Depmeier, Wulf; Albrecht-Schmitt, Thomas E.

    2011-02-22

    The first plutonium(III) borate, Pu2[B12O18(OH)4Br2(H2O)3]·0.5H2O, has been prepared by reacting plutonium(III) with molten boric acid under strictly anaerobic conditions. This compound contains a three-dimensional polyborate network with triangular holes that house the plutonium(III) sites. The plutonium sites in this compound are 9- and 10-coordinate and display atypical geometries.

  1. Oxidation of plutonium dioxide.

    PubMed

    Korzhavyi, Pavel A; Vitos, Levente; Andersson, David A; Johansson, Börje

    2004-04-01

    The physics and chemistry of the actinide elements form the scientific basis for rational handling of nuclear materials. In recent experiments, most unexpectedly, plutonium dioxide has been found to react with water to form higher oxides up to PuO(2.27), whereas PuO(2) had always been thought to be the highest stable oxide of plutonium. We perform a theoretical analysis of this complicated situation on the basis of total energies calculated within density functional theory combined with well-established thermodynamic data. The reactions of PuO(2) with either O(2) or H(2)O to form PuO(2+delta) are calculated to be endothermic: that is, in order to occur they require a supply of energy. However, our calculations show that PuO(2+delta) can be formed, as an intermediate product, by reactions with the products of radiolysis of water, such as H(2)O(2). PMID:15034561

  2. MOLDS FOR CASTING PLUTONIUM

    DOEpatents

    Anderson, J.W.; Miley, F.; Pritchard, W.C.

    1962-02-27

    A coated mold for casting plutonium comprises a mold base portion of a material which remains solid and stable at temperatures as high as the pouring temperature of the metal to be cast and having a thin coating of the order of 0.005 inch thick on the interior thereof. The coating is composed of finely divided calcium fluoride having a particle size of about 149 microns. (AEC)

  3. Utilization of principal component analysis on plutonium EXAFS data from the advanced photon source

    NASA Astrophysics Data System (ADS)

    Terry, Jeff; Schulze, Roland K.; Zocco, Thomas G.; Farr, J. Doug; Archuleta, Jeff; Ramos, Mike; Martinez, Ray; Pereyra, Ramiro; Lashley, Jason; Wasserman, Steve; Antonio, Mark; Skanthakumar, Suntharalingam; Soderholm, Lynne

    2000-07-01

    Since the 1941 discovery of plutonium (Pu) by Glenn Seaborg, this enigmatic metal has been the subject of intense scientific investigation. Despite these efforts, there is still much to be learned about the unusual physical and mechanical properties of plutonium and its alloys. In particular, unalloyed Pu undergoes six allotropic phase transformations upon cooling from the melt to room temperature. Many of these phase transformations result in large volume changes and produce low-symmetry crystal structures. These unusual characteristics have made the metallurgy of Pu and Pu alloys particularly challenging.

  4. Plutonium recovery from organic materials

    DOEpatents

    Deaton, R.L.; Silver, G.L.

    1973-12-11

    A method is described for removing plutonium or the like from organic material wherein the organic material is leached with a solution containing a strong reducing agent such as titanium (III) (Ti/sup +3None)/, chromium (II) (Cr/ sup +2/), vanadium (II) (V/sup +2/) ions, or ferrous ethylenediaminetetraacetate (EDTA), the leaching yielding a plutonium-containing solution that is further processed to recover plutonium. The leach solution may also contain citrate or tartrate ion. (Official Gazette)

  5. PROCESS OF PRODUCING SHAPED PLUTONIUM

    DOEpatents

    Anicetti, R.J.

    1959-08-11

    A process is presented for producing and casting high purity plutonium metal in one step from plutonium tetrafluoride. The process comprises heating a mixture of the plutonium tetrafluoride with calcium while the mixture is in contact with and defined as to shape by a material obtained by firing a mixture consisting of calcium oxide and from 2 to 10% by its weight of calcium fluoride at from 1260 to 1370 deg C.

  6. Manufacturing of Plutonium Tensile Specimens

    SciTech Connect

    Knapp, Cameron M

    2012-08-01

    Details workflow conducted to manufacture high density alpha Plutonium tensile specimens to support Los Alamos National Laboratory's science campaigns. Introduces topics including the metallurgical challenge of Plutonium and the use of high performance super-computing to drive design. Addresses the utilization of Abaqus finite element analysis, programmable computer numerical controlled (CNC) machining, as well as glove box ergonomics and safety in order to design a process that will yield high quality Plutonium tensile specimens.

  7. PLUTONIUM METALLOGRAPHY AT LOS ALAMOS

    SciTech Connect

    PEREYRA, RAMIRO A.; LOVATO, DARRYL

    2007-01-08

    From early days of the Manhattan program to today, scientists and engineers have continued to investigate the metallurgical properties of plutonium (Pu). Although issues like aging was not a concern to the early pioneers, today the reliability of our aging stockpile is of major focus. And as the country moves toward a new generation of weapons similar problems that the early pioneers faced such as compatibility, homogeneity and malleability have come to the forefront. And metallography will continue to be a principle tool for the resolution of old and new issues. Standard metallographic techniques are used for the preparation of plutonium samples. The samples are first cut with a slow speed idamond saw. After mounting in Epon 815 epoxy resin, the samples are ground through 600 grit silicon carbide paper. PF 5070 (a Freon substitute) is used as a coolant, lubricant, and solvent for most operations. Rough mechanical polished is done with 9-{mu} diamond using a nap less cloth, for example nylon or cotton. Final polish is done with 1-{mu} diamond on a nappy cloth such as sylvet. Ethyl alcohol is then used ultrasonically to clean the samples before electro polishing. The sample is then electro-polished and etched in an electrolyte containing 10% nitric acid, and 90% dimethyleneformalmide. Ethyl alcohol is used as a final cleaning agent. Although standard metallographic preparation techniques are used, there are several reasons why metallography of Pu is difficult and challenging. Firstly, because of the health hazards associated with its radioactive properties, sample preparation is conducted in glove boxes. Figure 1 shows the metallography line, in an R and D facility. Since they are designed to be negative in pressure to the laboratory, cross-contamination of abrasives is a major problem. In addition, because of safety concerns and waste issues, there is a limit to the amount of solvent that can be used. Secondly, Pu will readily hydride or oxidize when in contact

  8. Gamma radiation characteristics of plutonium dioxide fuel

    NASA Technical Reports Server (NTRS)

    Gingo, P. J.

    1969-01-01

    Investigation of plutonium dioxide as an isotopic fuel for Radioisotope Thermoelectric Generators yielded the isotopic composition of production-grade plutonium dioxide fuel, sources of gamma radiation produced by plutonium isotopes, and the gamma flux at the surface.

  9. Evaluation of Solute Clusters Associated with Bake-Hardening Response in Isothermal Aged Al-Mg-Si Alloys Using a Three-Dimensional Atom Probe

    NASA Astrophysics Data System (ADS)

    Aruga, Yasuhiro; Kozuka, Masaya; Takaki, Yasuo; Sato, Tatsuo

    2014-12-01

    Temporal changes in the number density, size distribution, and chemical composition of clusters formed during natural aging at room temperature and pre-aging at 363 K (90 °C) in an Al-0.62Mg-0.93Si (mass pct) alloy were evaluated using atom probe tomography. More than 10 million atoms were examined in the cluster analysis, in which about 1000 clusters were obtained for each material after various aging treatments. The statistically proven records show that both number density and the average radius of clusters in pre-aged materials are larger than in naturally aged materials. It was revealed that the fraction of clusters with a low Mg/Si ratio after natural aging for a short time is higher than with other aging treatments, regardless of cluster size. This indicates that Si-rich clusters form more easily after short-period natural aging, and that Mg atoms can diffuse into the clusters or possibly form another type of Mg-Si cluster after prolonged natural aging. The formation of large clusters with a uniform Mg/Si ratio is encouraged by pre-aging. It can be concluded that an increase of small clusters with various Mg/Si ratios does not promote the bake-hardening (BH) response, whereas large clusters with a uniform Mg/Si ratio play an important role in hardening during the BH treatment at 443 K (170 °C).

  10. Evaluation of Solute Clusters Associated with Bake-Hardening Response in Isothermal Aged Al-Mg-Si Alloys Using a Three-Dimensional Atom Probe

    NASA Astrophysics Data System (ADS)

    Aruga, Yasuhiro; Kozuka, Masaya; Takaki, Yasuo; Sato, Tatsuo

    2014-09-01

    Temporal changes in the number density, size distribution, and chemical composition of clusters formed during natural aging at room temperature and pre-aging at 363 K (90 °C) in an Al-0.62Mg-0.93Si (mass pct) alloy were evaluated using atom probe tomography. More than 10 million atoms were examined in the cluster analysis, in which about 1000 clusters were obtained for each material after various aging treatments. The statistically proven records show that both number density and the average radius of clusters in pre-aged materials are larger than in naturally aged materials. It was revealed that the fraction of clusters with a low Mg/Si ratio after natural aging for a short time is higher than with other aging treatments, regardless of cluster size. This indicates that Si-rich clusters form more easily after short-period natural aging, and that Mg atoms can diffuse into the clusters or possibly form another type of Mg-Si cluster after prolonged natural aging. The formation of large clusters with a uniform Mg/Si ratio is encouraged by pre-aging. It can be concluded that an increase of small clusters with various Mg/Si ratios does not promote the bake-hardening (BH) response, whereas large clusters with a uniform Mg/Si ratio play an important role in hardening during the BH treatment at 443 K (170 °C).

  11. Effect of Natural Aging and Cold Working on Microstructures and Mechanical Properties of Al-4.6Cu-0.5Mg-0.5Ag alloy

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Te; Lee, Sheng-Long; Bor, Hui-Yun; Lin, Jing-Chie

    2013-06-01

    This research investigates the effects of natural aging and cold working prior to artificial aging on microstructures and mechanical properties of Al-4.6Cu-0.5Mg-0.5Ag alloy. Mechanical properties relative to microstructure variations were elucidated by the observations of the optical microscope (OM), differential scanning calorimeter (DSC), electrical conductivity meter (pct IACS), and transmission electron microscopy (TEM). The results showed that natural aging treatment has little noticeable benefit on the quantity of precipitation strengthening phases and mechanical properties, but it increases the precipitation strengthening rate at the initial stage of artificial aging. Cold working brings more lattice defects which suppress Al-Cu (GP zone) and Mg-Ag clustering, and therefore the precipitation of Ω phase decreases. Furthermore, more dislocations are formed, leading to precipitate the more heterogeneous nucleation of θ' phase. The above-mentioned precipitation phenomena and strain hardening effect are more obvious with higher degrees of cold working.

  12. Influence of Chemical Composition on Rupture Properties at 1200 Degrees F. of Forged Chromium-Cobalt-Nickel-Iron Base Alloys in Solution-Treated and Aged Condition

    NASA Technical Reports Server (NTRS)

    Reynolds, E E; Freeman, J W; White, A E

    1951-01-01

    The influence of systematic variations of chemical composition on rupture properties at 1200 degrees F. was determined for 62 modifications of a basic alloy containing 20 percent chromium, 20 percent nickel, 20 percent cobalt, 3 percent molybdenum, 2 percent tungsten, 1 percent columbium, 0.15 percent carbon, 1.7 percent manganese, 0.5 percent silicon, 0.12 percent nitrogen and the balance iron. These modifications included individual variations of each of 10 elements present and simultaneous variations of molybdenum, tungsten, and columbium. Laboratory induction furnace heats were hot-forged to round bar stock, solution-treated at 2200 degrees F., and aged at 1400 degrees F. The melting and fabrication conditions were carefully controlled in order to minimize all variable effects on properties except chemical composition. Information is presented which indicates that melting and hot-working conditions play an important role in high-temperature properties of alloys of the type investigated.

  13. Effect of Welding Parameters and Aging Process on the Mechanical Properties of Friction Stir-Welded 6063-T4 Al Alloy

    NASA Astrophysics Data System (ADS)

    Toktaş, Alaaddin; Toktaş, Gülcan

    2012-06-01

    6063-T4 Al alloy was friction stir welded at various tool rotations (800, 1120, and 1600 rpm) and welding speeds (200 and 315 mm/min) using a specially manufactured tool with a height-adjustable and right-hand-threaded pin. The postweld aging process (at 185 °C for 7 h) was applied to a group of the welded plates. In this study, the effects of the welding parameters and the postweld aging treatment on the microstructural and mechanical properties of 6063-T4 Al alloy were studied. The maximum weld temperatures during the welding process were recorded, and the fracture surfaces of tensile specimens were examined using a scanning electron microscope. The homogeneous hardness profiles were obtained for all the weldings with no trace of softening regions. It was observed that the ultimate tensile strengths (UTS) increased slightly (on average by approx. 8%) and the percent elongations decreased (on average by approx. 33%) by the postweld aging treatment. The maximum bending forces ( F max) of all the welds were less than that of the base metal. It was observed that the F max values increased after the postweld aging process at the welding speed of 315 mm/min and decreased at the welding speed of 200 mm/min.

  14. The impact of aging pre-treatment on the hot deformation behavior of alloy 800H at 750 °C

    NASA Astrophysics Data System (ADS)

    Cao, Yu; Di, Hongshuang; Misra, R. D. K.

    2014-09-01

    The influence of aging pre-treatment on the hot deformation of a commercial alloy 800H was investigated through uniaxial compression tests. Aging pre-treatments were performed at 750 °C for 0 h, 5 h, 10 h, 20 h and 50 h, followed by compression tests at 750 °C with strain rates of 0.01 s-1, 0.1 s-1 and 1 s-1. The flow curves signified that the peak stress decreased evidently with increasing aging time. The microstructural analysis of alloy 800H after aging at 750 °C for 50 h indicated that the predominant precipitates are block-shaped Cr23C6 and cube-shaped Ti(C,N). The formation of grain-boundary Cr23C6 results in the segregation of Cr and C with the depletion of Ni at the grain boundaries. The kernel average misorientation maps after hot deformation demonstrates that the grain-boundary precipitates induce the pinning force to change the distribution of local misorientation and two different deformation patterns were defined to characterize the substructure developed near the grain boundaries.

  15. PREPARATION OF HALIDES OF PLUTONIUM

    DOEpatents

    Garner, C.S.; Johns, I.B.

    1958-09-01

    A dry chemical method is described for preparing plutonium halides, which consists in contacting plutonyl nitrate with dry gaseous HCl or HF at an elevated temperature. The addition to the reaction gas of a small quantity of an oxidizing gas or a reducing gas will cause formation of the tetra- or tri-halide of plutonium as desired.

  16. SEPARATION OF PLUTONIUM FROM URANIUM

    DOEpatents

    Feder, H.M.; Nuttall, R.L.

    1959-12-15

    A process is described for extracting plutonium from powdered neutron- irradiated urarium metal by contacting the latter, while maintaining it in the solid form, with molten magnesium which takes up the plutonium and separating the molten magnesium from the solid uranium.

  17. SOLVENT EXTRACTION PROCESS FOR PLUTONIUM

    DOEpatents

    Anderson, H.H.; Asprey, L.B.

    1960-02-01

    A process of separating plutonium in at least the tetravalent state from fission products contained in an aqueous acidic solution by extraction with alkyl phosphate is reported. The plutonium can then be back-extracted from the organic phase by contact with an aqueous solution of sulfuric, phosphoric, or oxalic acid as a complexing agent.

  18. METHOD OF REDUCING PLUTONIUM COMPOUNDS

    DOEpatents

    Johns, I.B.

    1958-06-01

    A method is described for reducing plutonium compounds in aqueous solution from a higher to a lower valence state. This reduction of valence is achieved by treating the aqueous solution of higher valence plutonium compounds with hydrogen in contact with an activated platinum catalyst.

  19. The Concentration of (236)Pu Daughters in Plutonium for Application to MOX Production from Plutonium from Dismantled US Nuclear Weapons

    SciTech Connect

    Sampson, T.E.; Cremers, T.L.

    2001-05-01

    The isotope {sup 236}Pu in the weapons-grade plutonium to be used in the US MOX (mixed-oxide) plant is of concern because the daughter products of {sup 236}Pu are sources of high-energy gamma rays. The {sup 208}Tl daughter of {sup 236}Pu emits intense, high-energy gamma rays that are important for radiation exposure calculations for plant design. It is generally thought that the concentrations of {sup 236}Pu and its daughters are well below 10{sup {minus}10}, but these concentrations are generally below the detection limits of most analytical techniques. One technique that can be used to determine the concentration {sup 208}Tl is the direct measurement of the intensity of the {sup 208}Tl gamma rays in the gamma-ray spectrum from plutonium. Thallium-208 will be in equilibrium with {sup 228}Th, and may very well be in equilibrium with {sup 232}U for most aged plutonium samples. We have used the FRAM isotopic analysis software to analyze dozens of archived high-resolution gamma ray spectra from various samples of US and foreign plutonium. We are able to quantify the ratio of minor isotopes with measurable gamma-ray emissions to the major isotope of plutonium and hence, through the measurement of the plutonium isotopic distribution of the sample, to elemental plutonium itself. Excluding items packaged in fluoropolymer vials, all samples analyzed with {sup 240}Pu < 9% gave {sup 228}Th/Pu ratios < 3.4 e-012 and all samples of US-produced plutonium, including {sup 240}Pu values up to 16.4%, gave {sup 228}Th/Pu ratios < 9.4 e-012. None of these values is significant from a radiation dose standpoint.

  20. Effects of aging treatment and heat input on the microstructures and mechanical properties of TIG-welded 6061-T6 alloy joints

    NASA Astrophysics Data System (ADS)

    Peng, Dong; Shen, Jun; Tang, Qin; Wu, Cui-ping; Zhou, Yan-bing

    2013-03-01

    Aging treatment and various heat input conditions were adopted to investigate the microstructural evolution and mechanical properties of TIG welded 6061-T6 alloy joints by microstructural observations, microhardness tests, and tensile tests. With an increase in heat input, the width of the heat-affected zone (HAZ) increases and grains in the fusion zone (FZ) coarsen. Moreover, the hardness of the HAZ decreases, whereas that of the FZ decreases initially and then increases with an increase in heat input. Low heat input results in the low ultimate tensile strength of the welded joints due to the presence of partial penetrations and pores in the welded joints. After a simple artificial aging treatment at 175°C for 8 h, the microstructure of the welded joints changes slightly. The mechanical properties of the welded joints enhance significantly after the aging process as few precipitates distribute in the welded seam.

  1. Effect of equal-channel angular pressing and aging on the microstructure and mechanical properties of an Al-Cu-Mg-Si alloy

    NASA Astrophysics Data System (ADS)

    Gazizov, M. R.; Dubina, A. V.; Zhemchuzhnikova, D. A.; Kaibyshev, R. O.

    2015-07-01

    The effect of intermediate equal-channel angular pressing (ECAP) and final aging at 170°C on the mechanical properties and microstructure of aluminum alloy belonging to Al-Cu-Mg-Si system stress with a Cu/Mg ratio (AA2014) is considered. After quenching and aging (treatment T6), the yield stress (σ0.2) and ultimate tensile strength (σu) are ˜415 and ˜450 MPa, respectively; the elongation to fracture (δ) is 4.2%. The precipitation strengthening is reached due to the precipitation of θ″-, θ'-, β″-, and Q'/ C-phase particles. After intermediate ECAP and subsequent aging for 0.5 h, σ0.2 and σu increase to 470 and 535 MPa, respectively; δ increases to ˜9.5%. The plastic deformation leads to the formation of a microstructure that consists of deformation bands characterized by a high density of dislocations. During aging for 0.5 h, the partial decomposition of supersaturated solid solution and formation of segregations within grains and at dislocations and precipitation of the Guinier-Preston zones and β″ phase also occur; all of this ensure the maximum increase in the strength of the AA2014 alloy. As the aging time increases to 8 h, the slight decrease in both σ0.2 and σu to 465 and 515 MPa and δ to ˜6% takes place. It has been shown that the intermediate ECAP does not affect the sequence of the precipitation of main strengthening θ″ and θ' phases during aging. However, in this case, the volume fraction of strengthening particles decreases significantly and their dispersivity increases.

  2. An Extended Age-Hardening Model for Al-Mg-Si Alloys Incorporating the Room-Temperature Storage and Cold Deformation Process Stages

    NASA Astrophysics Data System (ADS)

    Myhr, Ole Runar; Grong, Øystein; Schäfer, Carmen

    2015-12-01

    In this article, a new age-hardening model for Al-Mg-Si alloys is presented (named NaMo-Version 2), which takes into account the combined effect of cold deformation and prolonged room-temperature storage on the subsequent response to artificial aging. As a starting point, the original physical framework of NaMo-Version 1 is revived and used as a basis for the extension. This is permissible, since a more in-depth analysis of the underlying particle-dislocation interactions confirms previous expectations that the simplifying assumption of spherical precipitates is not crucial for the final outcome of the calculations, provided that the yield strength model is calibrated against experimental data. At the same time, the implementation of the Kampmann-Wagner formalism means that the different microstructure models can be linked together in a manner that enforces solute partitioning and competition between the different hardening phases which form during aging ( e.g., clusters, β″ and β'). In a calibrated form, NaMo-Version 2 exhibits a high degree of predictive power, as documented by comparison with experiments, using both dedicated nanostructure and yield strength data as a basis for the validation. Hence, the model is deemed to be well-suited for simulation of thermomechanical processing of Al-Mg-Si alloys involving cold-working operations like sheet forming and stretch bending in combination with heat treatment and welding.

  3. Influence of multi-step heat treatments in creep age forming of 7075 aluminum alloy: Optimization for springback, strength and exfoliation corrosion

    SciTech Connect

    Arabi Jeshvaghani, R.; Zohdi, H.; Shahverdi, H.R.; Bozorg, M.; Hadavi, S.M.M.

    2012-11-15

    Multi-step heat treatments comprise of high temperature forming (150 Degree-Sign C/24 h plus 190 Degree-Sign C for several minutes) and subsequent low temperature forming (120 Degree-Sign C for 24 h) is developed in creep age forming of 7075 aluminum alloy to decrease springback and exfoliation corrosion susceptibility without reduction in tensile properties. The results show that the multi-step heat treatment gives the low springback and the best combination of exfoliation corrosion resistance and tensile strength. The lower springback is attributed to the dislocation recovery and more stress relaxation at higher temperature. Transmission electron microscopy observations show that corrosion resistance is improved due to the enlargement in the size and the inter-particle distance of the grain boundaries precipitates. Furthermore, the achievement of the high strength is related to the uniform distribution of ultrafine {eta} Prime precipitates within grains. - Highlights: Black-Right-Pointing-Pointer Creep age forming developed for manufacturing of aircraft wing panels by aluminum alloy. Black-Right-Pointing-Pointer A good combination of properties with minimal springback is required in this component. Black-Right-Pointing-Pointer This requirement can be improved through the appropriate heat treatments. Black-Right-Pointing-Pointer Multi-step cycles developed in creep age forming of AA7075 for improving of springback and properties. Black-Right-Pointing-Pointer Results indicate simultaneous enhancing the properties and shape accuracy (lower springback).

  4. Experience making mixed oxide fuel with plutonium from dismantled weapons

    SciTech Connect

    Blair, H.T.; Ramsey, K.B.

    1995-12-31

    Mixed depleted UO{sub 2} and PuO{sub 2} (MOX) pellets prototypic of fuel proposed for use in commercial power reactors were made with plutonium recovered from dismantled weapons. We characterized plutonium dioxide powders that were produced at the Los Alamos and Lawrence Livermore National Laboratories (LANL and LLNL) using various methods to recover the plutonium from weapons parts and to convert It to oxide. The gallium content of the PUO{sub 2} prepared at LANL was the same as in the weapon alloy while the content of that prepared at LLNL was less. The MOX was prepared with a five weight percent plutonium content. We tested various MOX powders milling methods to improve homogeneity and found vibratory milling superior to ball milling. The sintering behavior of pellets made with the PuO{sub 2} from the two laboratories was similar. We evaluated the effects of gallium and of erbium and gadolinium, that are added to the MOX fuel as deplorable neutron absorbers, on the pellet fabrication process and an the sintered pellets. The gallium content of the sintered pellets was <10 ppm, suggesting that the gallium will not be an issue in the reactor, but that it will be an Issue in the operation of the fuel fabrication processing equipment unless it is removed from the PuO{sub 2} before it is blended with the UO{sub 2}.

  5. Plutonium Focus Area research and development plan. Revision 1

    SciTech Connect

    1996-11-01

    The Department of Energy (DOE) committed to a research and development program to support the technology needs for converting and stabilizing its nuclear materials for safe storage. The R and D Plan addresses five of the six material categories from the 94-1 Implementation Plan: plutonium (Pu) solutions, plutonium metals and oxides, plutonium residues, highly enriched uranium, and special isotopes. R and D efforts related to spent nuclear fuel (SNF) stabilization were specifically excluded from this plan. This updated plan has narrowed the focus to more effectively target specific problem areas by incorporating results form trade studies. Specifically, the trade studies involved salt; ash; sand, slag, and crucible (SS and C); combustibles; and scrub alloy. The plan anticipates possible disposition paths for nuclear materials and identifies resulting research requirements. These requirements may change as disposition paths become more certain. Thus, this plan represents a snapshot of the current progress and will continue to be updated on a regular basis. The paper discusses progress in safeguards and security, plutonium stabilization, special isotopes stabilization, highly-enriched uranium stabilization--MSRE remediation project, storage technologies, engineered systems, core technology, and proposed DOE/Russian technology exchange projects.

  6. Microstructure Evolution in a Cu-0.5Cr-0.2Zr Alloy Subjected to Equal Channel Angular Pressing, Rolling or Aging

    NASA Astrophysics Data System (ADS)

    Alexandrov, Igor V.; Sitdikov, Vil D.; Abramova, Marina M.; Sarkeeva, Elena A.; Wei, Kun Xia; Wei, Wei

    2016-08-01

    The evolution of microstructure in the Cu-0.5%Cr-0.2%Zr alloy subjected to thermomechanical treatment has been studied by means of the x-ray analysis. The workpieces have been subjected to 1, 2, 4 and 8 passes of equal channel angular pressing, plain cold rolling and aging treatment. The results of the XRD investigations reflect the evolution of the lattice parameter, the size of coherently scattering domains, the elastic microdistortions and the dislocation density in Cu matrix. The observed changes in the microstructure are explained by the competition between the developing defects and precipitation of the Cr phase particles from the Cu matrix.

  7. SEPARATION OF URANIUM, PLUTONIUM AND FISSION PRODUCTS FROM NEUTRON- BOMBARDED URANIUM

    DOEpatents

    Martin, A.E.; Johnson, I.; Burris, L. Jr.; Winsch, I.O.; Feder, H.M.

    1962-11-13

    A process is given for removing plutonium and/or fission products from uranium fuel. The fuel is dissolved in molten zinc--magnesium (10 to 18% Mg) alloy, more magnesium is added to obtain eutectic composition whereby uranium precipitates, and the uranium are separated from the Plutoniumand fission-product- containing eutectic. (AEC)

  8. Russian youth forum special session: Youth and the global political challenges of plutonium

    SciTech Connect

    Browne, J.C.

    1998-12-31

    This paper, given by the director of the Los Alamos National Laboratory, briefly points out the unusual properties of plutonium, for example, its most unusual electronic structure, its sensitivity to changes in temperature, pressure, and chemical alloying, and its great propensity for oxygen and hydrogen. The combination of nuclear and electronic processes it undergoes complicate the behavior also.

  9. SOLVENT EXTRACTION PROCESS FOR PLUTONIUM

    DOEpatents

    Seaborg, G.T.

    1959-04-14

    The separation of plutonium from aqueous inorganic acid solutions by the use of a water immiscible organic extractant liquid is described. The plutonium must be in the oxidized state, and the solvents covered by the patent include nitromethane, nitroethane, nitropropane, and nitrobenzene. The use of a salting out agents such as ammonium nitrate in the case of an aqueous nitric acid solution is advantageous. After contacting the aqueous solution with the organic extractant, the resulting extract and raffinate phases are separated. The plutonium may be recovered by any suitable method.

  10. Low temperature oxidation of plutonium

    SciTech Connect

    Nelson, Art J.; Roussel, Paul

    2013-05-15

    The initial oxidation of gallium stabilized {delta}-plutonium metal at 193 K has been followed using x-ray photoelectron spectroscopy. On exposure to Langmuir quantities of oxygen, plutonium rapidly forms a trivalent oxide followed by a tetravalent plutonium oxide. The growth modes of both oxides have been determined. Warming the sample in vacuum, the tetravalent oxide reduces to the trivalent oxide. The kinetics of this reduction reaction have followed and the activation energy has been determined to be 38.8 kJ mol{sup -1}.

  11. The structure of plutonium(IV) oxide as hydrolysed clusters in aqueous suspensions.

    PubMed

    Ekberg, Christian; Larsson, Kristian; Skarnemark, Gunnar; Ödegaard-Jensen, Arvid; Persson, Ingmar

    2013-02-14

    The behavior of plutonium still puzzles scientists 70 years after its discovery. There are several factors making the chemistry of plutonium interesting including its ability to keep several oxidation states. Another unique property is that the oxidation states +III, +IV, +V and +VI may exist simultaneously in solution. Another property plutonium shares with some other tetravalent metal ions is the ability to form stable polynuclear complexes or colloids. The structures of freshly prepared and five-year old plutonium(IV) colloids are compared with crystalline plutonium(IV) oxide using Pu L(3)-edge EXAFS. It was shown that as the plutonium colloids age they do in fact shrink in size, contrary to previous expectations. The aged colloidal particles are indeed very small with only 3-4 plutonium atoms, and with a structure very similar to solid plutonium(IV) oxide, but with somewhat shorter mean Pu-O bond and Pu···Pu distances indicating a partial oxidation. The very small size of the colloidal particles is further supported by the fact that they do not sediment on heavy ultra-centrifugation. PMID:23175453

  12. PLUTONIUM BURDENS IN PEOPLE LIVING AROUND THE ROCKY FLATS PLANT

    EPA Science Inventory

    A study was conducted to determine whether the tissues of people who lived near to or downwind from the Rocky Flats nuclear weapons facility in Colorado contained more plutonium than the tissues from people who lived farther away. Information was collected on the age, sex, smokin...

  13. Aging.

    PubMed

    Park, Dong Choon; Yeo, Seung Geun

    2013-09-01

    Aging is initiated based on genetic and environmental factors that operate from the time of birth of organisms. Aging induces physiological phenomena such as reduction of cell counts, deterioration of tissue proteins, tissue atrophy, a decrease of the metabolic rate, reduction of body fluids, and calcium metabolism abnormalities, with final progression onto pathological aging. Despite the efforts from many researchers, the progression and the mechanisms of aging are not clearly understood yet. Therefore, the authors would like to introduce several theories which have gained attentions among the published theories up to date; genetic program theory, wear-and-tear theory, telomere theory, endocrine theory, DNA damage hypothesis, error catastrophe theory, the rate of living theory, mitochondrial theory, and free radical theory. Although there have been many studies that have tried to prevent aging and prolong life, here we introduce a couple of theories which have been proven more or less; food, exercise, and diet restriction. PMID:24653904

  14. Aging

    PubMed Central

    Park, Dong Choon

    2013-01-01

    Aging is initiated based on genetic and environmental factors that operate from the time of birth of organisms. Aging induces physiological phenomena such as reduction of cell counts, deterioration of tissue proteins, tissue atrophy, a decrease of the metabolic rate, reduction of body fluids, and calcium metabolism abnormalities, with final progression onto pathological aging. Despite the efforts from many researchers, the progression and the mechanisms of aging are not clearly understood yet. Therefore, the authors would like to introduce several theories which have gained attentions among the published theories up to date; genetic program theory, wear-and-tear theory, telomere theory, endocrine theory, DNA damage hypothesis, error catastrophe theory, the rate of living theory, mitochondrial theory, and free radical theory. Although there have been many studies that have tried to prevent aging and prolong life, here we introduce a couple of theories which have been proven more or less; food, exercise, and diet restriction. PMID:24653904

  15. PLUTONIUM-HYDROGEN REACTION PRODUCT, METHOD OF PREPARING SAME AND PLUTONIUM POWDER THEREFROM

    DOEpatents

    Fried, S.; Baumbach, H.L.

    1959-12-01

    A process is described for forming plutonlum hydride powder by reacting hydrogen with massive plutonium metal at room temperature and the product obtained. The plutonium hydride powder can be converted to plutonium powder by heating to above 200 deg C.

  16. Plutonium Immobilization Can Inspection System

    SciTech Connect

    Kriikku, E.

    2000-12-12

    The Savannah River Site (SRS) will immobilize excess plutonium in the proposed Plutonium Immobilization Plant (PIP) as part of Department of Energy's two-track approach for the disposition of weapons-usable plutonium. The PIP will utilize the ceramic can-in-canister technology in a process that mixes plutonium with ceramic formers and neutron absorbers, presses the mixture into a ceramic puck-like form, sinters the pucks in a furnace, loads the pucks into cans, and places the cans into large canisters. The canisters will subsequently be filled with high level waste glass in the Defense Waste Processing Facility for eventual disposal in a geologic repository. This paper will discuss the PIP can inspection components, control system, and test results.

  17. Discontinuous coarsening behavior of Ni(2)MnAl intermetallic compound during isothermal aging treatment of Fe-Mn-Ni-Al alloys.

    PubMed

    Heo, Yoon-Uk; Takeguchi, Masaki; Furuya, Kazuo; Lee, Hu-Chul

    2010-08-01

    The discontinuous reaction of the Ni(2)MnAl intermetallic phase was investigated during the aging of a solution-treated Fe-8.3Mn-8.2Ni-4.2Al alloy. During aging, Ni(2)MnAl lamellae formed at the prior austenite grain boundaries and twin boundaries and grew into the neighboring grains. The presence of continuously precipitated fine Ni(2)MnAl particles before the growth of the discontinuously precipitated lamellae was confirmed by dark-field transmission electron microscopy, and it was concluded that the present reaction is a type of discontinuous coarsening process, alpha' + Ni(2)MnAl (continuous precipitation) --> alpha + Ni(2)MnAl (discontinuous coarsening). The chemical driving force and the reduction of the total coherent strain energy were suggested to be the driving force for the discontinuous coarsening reaction. PMID:20551447

  18. Phase field simulation of coherent precipitation of Ni4Ti3 particles during stress-assisted aging of a porous NiTi alloy

    NASA Astrophysics Data System (ADS)

    Ke, C. B.; Cao, S. S.; Zhang, X. P.

    2015-07-01

    Morphological evolution and growth behavior of Ni4Ti3 precipitates during stress-assisted aging of a porous NiTi alloy are investigated by means of phase field method through introducing nano-scale volume elements around the micro-sized pores. The model naturally takes into account the stress redistribution arising from the structural and elastic inhomogeneity across the matrix of the porous NiTi alloy aged under compressive stress. Simulation results show that the orientation and distribution of Ni4Ti3 precipitates in different volume elements are evidently distinct. A gradient distribution in terms of the area fraction of Ni4Ti3 precipitates across the selected volume elements can be seen. The area fraction and average size of Ni4Ti3 precipitates are dependent on position of the volume element, i.e. distance to the pore. Differences in the orientation, distribution and average size of Ni4Ti3 precipitates among different selected volume elements are attributed to the disparities of stress states in the volume elements.

  19. IODATE METHOD FOR PURIFYING PLUTONIUM

    DOEpatents

    Stoughton, R.W.; Duffield, R.B.

    1958-10-14

    A method is presented for removing radioactive fission products from aqueous solutions containing such fission products together with plutonium. This is accomplished by incorporating into such solutions a metal iodate precipitate to remove fission products which form insoluble iodates. Suitable metal iodates are those of thorium and cerium. The plutonium must be in the hexavalent state and the pH of the solution must be manintained at less than 2.

  20. METHOD OF PREPARING PLUTONIUM TETRAFLUORIDE

    DOEpatents

    Beede, R.L.; Hopkins, H.H. Jr.

    1959-11-17

    C rystalline plutonium tetrafluoride is precipitated from aqueous up to 1.6 N mineral acid solutions of a plutorium (IV) salt with fluosilicic acid anions, preferably at room temperature. Hydrogen fluoride naay be added after precipitation to convert any plutonium fluosilicate to the tetrafluoride and any silica to fluosilicic acid. This process results in a purer product, especially as to iron and aluminum, than does the precipitation by the addition of hydrogen fluoride.

  1. In situ SEM studies of the transformation sequence of multistage martensitic transformations in aged Ti-50.8 at.% Ni alloys

    NASA Astrophysics Data System (ADS)

    Karbakhsh Ravari, B.; Nishida, M.

    2013-06-01

    The transformation behaviour of the multistage martensitic transformation in aged Ti-50.8 at.% Ni alloys was investigated by differential scanning calorimetry (DSC) and in situ scanning electron microscopy (SEM). The specimens aged from 673 to 748 K for 3.6 ks under an unregulated heat treatment atmosphere exhibited the double-stage transformation during cooling. The quadruple-stage transformation was observed in the specimens aged at 773 and 798 K, and the triple-stage transformation appeared in the specimen aged at 823 K under an unregulated heat treatment atmosphere. The distribution and size of Ti3Ni4 precipitates were heterogeneous in these specimens. The single-stage transformation in the specimen aged at 848 K was similar to that of the solution-treated specimen. In the forward quadruple-stage transformation, the R-phase transformation occurred in the intermediate region and around the grain boundary. The first martensitic transformation, which corresponded to the M1 peak in the DSC cooling curve, took place in the intermediate region of grains via the R phase. The second transformation, which corresponded to the M2 peak, occurred around the grain boundary via the R phase. The final transformation, which corresponded to the M3 peak, arose directly from the B2 parent phase at the grain centre. The transformation sequence and areas described above were quantitatively verified by comparing the SEM observations with the DSC measurements. The transformation sequence of the triple-stage transformation was also discussed.

  2. Pu-Zr alloy for high-temperature foil-type fuel

    DOEpatents

    McCuaig, Franklin D.

    1977-01-01

    A nuclear reactor fuel alloy consists essentially of from slightly greater than 7 to about 4 w/o zirconium, balance plutonium, and is characterized in that the alloy is castable and is rollable to thin foils. A preferred embodiment of about 7 w/o zirconium, balance plutonium, has a melting point substantially above the melting point of plutonium, is rollable to foils as thin as 0.0005 inch thick, and is compatible with cladding material when repeatedly cycled to temperatures above 650.degree. C. Neutron reflux densities across a reactor core can be determined with a high-temperature activation-measurement foil which consists of a fuel alloy foil core sandwiched and sealed between two cladding material jackets, the fuel alloy foil core being a 7 w/o zirconium, plutonium foil which is from 0.005 to 0.0005 inch thick.

  3. Pu-ZR Alloy high-temperature activation-measurement foil

    DOEpatents

    McCuaig, Franklin D.

    1977-08-02

    A nuclear reactor fuel alloy consists essentially of from slightly greater than 7 to about 4 w/o zirconium, balance plutonium, and is characterized in that the alloy is castable and is rollable to thin foils. A preferred embodiment of about 7 w/o zirconium, balance plutonium, has a melting point substantially above the melting point of plutonium, is rollable to foils as thin as 0.0005 inch thick, and is compatible with cladding material when repeatedly cycled to temperatures above 650.degree. C. Neutron flux densities across a reactor core can be determined with a high-temperature activation-measurement foil which consists of a fuel alloy foil core sandwiched and sealed between two cladding material jackets, the fuel alloy foil core being a 7 w/o zirconium, plutonium foil which is from 0.005 to 0.0005 inch thick.

  4. Ageing behaviour of an Fe-20Ni-1.8Mn-1.6Ti-0.59Al (wt%) maraging alloy: clustering, precipitation and hardening

    SciTech Connect

    Pereloma, E.V. . E-mail: elena.pereloma@spme.monash.edu.au; Shekhter, A.; Miller, M.K.; Ringer, S.P.

    2004-11-08

    Changes in the solute distribution as well as the evolution of precipitation, microstructure and mechanical properties have been studied in an experimental maraging Fe-20Ni-1.8Mn-1.5Ti-0.59Al (wt%) alloy during ageing at 550 deg C. An initial hardening reaction within 5 s is reported, which is remarkable in terms of extent and rapidity. This strengthening was caused by the formation of complex multi-component atomic co-clusters containing primarily Ni-Ti-Al as well as some Mn. This cluster strengthened condition produced the optimum toughness observed throughout the ageing sequence. After 60 s ageing, the appearance of discrete precipitation of needle-shaped {eta}-Ni{sub 3}Ti particles was associated with a second rise in hardness towards an eventual peak at 600 s. This precipitation hardening was accompanied by an increase in tensile strength and a decrease in ductility. A reverse transformation of martensite to austenite occurs progressively during ageing and this contributes to the initial and secondary softening.

  5. Taguchi Optimization on the Initial Thickness and Pre-aging of Nano-/Ultrafine-Grained Al-0.2 wt.%Sc Alloy Produced by ARB

    NASA Astrophysics Data System (ADS)

    Yousefieh, Mohammad; Tamizifar, Morteza; Boutorabi, Seyed Mohammad Ali; Borhani, Ehsan

    2016-08-01

    In this study, Taguchi design method with L9 orthogonal array has been used to optimize the initial thickness and pre-aging parameters (temperature and time) for the mechanical properties of Al-0.2 wt.% Sc alloy heavily deformed by accumulative roll bonding (ARB) up to ten cycles. Analysis of variance was performed on the measured data and signal-to-noise ratios. It was found that the pre-aging temperature has the most significant parameter affecting the mechanical properties by percentage contribution of 64.51%. Pre-aging time (19.29%) has the next most significant effect, while initial thickness (5.31%) has statistically less significant effect. In order to confirm experimental conclusions, verification experiments were carried out at optimum working conditions. Under these conditions, the yield strength was 6.51 times higher and toughness was 6.86% lower compared with the starting Al-Sc material. Moreover, mean grain size was decreased to 220 nm by setting the control parameters, which was the lowest value obtained in this study. It was concluded that the Taguchi method was found to be a promising technique to obtain the optimum conditions for such studies. Consequently, by controlling the parameter levels, the high-strength and high-toughness Al-Sc samples were fabricated through pre-aging and subsequent ARB process.

  6. Plutonium focus area

    SciTech Connect

    1996-08-01

    To ensure research and development programs focus on the most pressing environmental restoration and waste management problems at the U.S. Department of Energy (DOE), the Assistant Secretary for the Office of Environmental Management (EM) established a working group in August 1993 to implement a new approach to research and technology development. As part of this new approach, EM developed a management structure and principles that led to the creation of specific Focus Areas. These organizations were designed to focus the scientific and technical talent throughout DOE and the national scientific community on the major environmental restoration and waste management problems facing DOE. The Focus Area approach provides the framework for intersite cooperation and leveraging of resources on common problems. After the original establishment of five major Focus Areas within the Office of Technology Development (EM-50, now called the Office of Science and Technology), the Nuclear Materials Stabilization Task Group (EM-66) followed the structure already in place in EM-50 and chartered the Plutonium Focus Area (PFA). The following information outlines the scope and mission of the EM, EM-60, and EM-66 organizations as related to the PFA organizational structure.

  7. Plutonium solution analyzer

    SciTech Connect

    Burns, D.A.

    1994-09-01

    A fully automated analyzer has been developed for plutonium solutions. It was assembled from several commercially available modules, is based upon segmented flow analysis, and exhibits precision about an order of magnitude better than commercial units (0.5%-O.05% RSD). The system was designed to accept unmeasured, untreated liquid samples in the concentration range 40-240 g/L and produce a report with sample identification, sample concentrations, and an abundance of statistics. Optional hydraulics can accommodate samples in the concentration range 0.4-4.0 g/L. Operating at a typical rate of 30 to 40 samples per hour, it consumes only 0.074 mL of each sample and standard, and generates waste at the rate of about 1.5 mL per minute. No radioactive material passes through its multichannel peristaltic pump (which remains outside the glovebox, uncontaminated) but rather is handled by a 6-port, 2-position chromatography-type loop valve. An accompanying computer is programmed in QuickBASIC 4.5 to provide both instrument control and data reduction. The program is truly user-friendly and communication between operator and instrument is via computer screen displays and keyboard. Two important issues which have been addressed are waste minimization and operator safety (the analyzer can run in the absence of an operator, once its autosampler has been loaded).

  8. Lung Cancer Risks from Plutonium: An Updated Analysis of Data from the Mayak Worker Cohort

    PubMed Central

    Gilbert, E. S.; Sokolnikov, M. E.; Preston, D. L.; Schonfeld, S. J.; Schadilov, A. E.; Vasilenko, E. K.; Koshurnikova, N. A.

    2013-01-01

    Workers at the Mayak nuclear facility in the Russian Federation offer a unique opportunity to evaluate health risks from exposure to inhaled plutonium. Risks of mortality from lung cancer, the most serious carcinogenic effect of plutonium, were evaluated in 14,621 Mayak workers who were hired in the period from 1948–1982, followed for at least 5 years, and either monitored for plutonium or never worked with plutonium. Over the follow-up period from 1953–2008, there were 486 deaths from lung cancer, 446 of them in men. In analyses that were adjusted for external radiation dose and smoking, the plutonium excess relative risk (ERR) per Gy declined with attained age and was higher for females than for males. The ERR per Gy for males at age 60 was 7.4 (95% CI: 5.0–11) while that for females was 24 (95% CI: 11–56). When analyses were restricted to plutonium doses <0.2 Gy, the ERR per Gy for males at age 60 was similar: 7.0 (95% CI: 2.5–13). Of the 486 lung cancer deaths, 105 (22%) were attributed to plutonium exposure and 29 (6%) to external exposure. Analyses of the 12,708 workers with information on smoking indicated that the relationship of plutonium exposure and smoking was likely sub-multiplicative (P = 0.011) and strongly indicated that it was super-additive (P < 0.001). Although extensive efforts have been made to improve plutonium dose estimates in this cohort, they are nevertheless subject to large uncertainties. Large bioassay measurement errors alone are likely to have resulted in serious underestimation of risks, whereas other sources of uncertainty may have biased results in ways that are difficult to predict. PMID:23391147

  9. Extrapulmonary organ distribution of plutonium in healthy workers exposed by chronic inhalation at the Mayak production association.

    PubMed

    Suslova, K G; Khokhryakov, V F; Tokarskaya, Z B; Nifatov, A P; Krahenbuhl, M P; Miller, S C

    2002-04-01

    The systemic distribution of plutonium was determined for "healthy" workers who chronically inhaled plutonium at the radiochemical plants of the Mayak Production Association. The data were obtained by radiochemical analysis of soft tissues and bones samples collected upon autopsy of 120 workers who died from acute coronary diseases and accidents. The soft tissue samples were wet-ashed using nitric acid and hydrogen peroxide. Bone samples were ashed in a muffle furnace at 500 degrees C. Plutonium was extracted on anionite and coprecipitated with bismuth phosphate. The precipitation was blended with ZnS powder, and the alpha-activity was measured by ZnS solid scintillation counting in a low-background alpha radiometer. Twenty-five years after the beginning of inhalation exposures, the average percentage of plutonium in the skeleton and liver was 50% and 42% of systemic burden, respectively. A multivariate regression was used to quantify the effects of exposure time, "transportability" of the various compounds, plutonium body content, and age on systemic plutonium distribution. The early retention of plutonium in the liver is assumed to be greater than that in the skeleton. The initial distribution of plutonium between the liver and the skeleton, immediately after entering the circulatory system, was 50:38%, respectively. With time, the fraction of plutonium found in the liver decreased, while the fraction in the skeleton increased at a rate of 0.5% y(-1) of systemic deposition. Exposure time had a greater effect on the relative retention of plutonium in the main organs when compared to age. The statistical estimates that characterized the relative plutonium distribution were less stable for the liver than for the skeleton, likely due to the slower turnover of skeletal tissues and the retention of plutonium in bone. PMID:11906132

  10. Selecting a plutonium vitrification process

    SciTech Connect

    Jouan, A.

    1996-05-01

    Vitrification of plutonium is one means of mitigating its potential danger. This option is technically feasible, even if it is not the solution advocated in France. Two situations are possible, depending on whether or not the glass matrix also contains fission products; concentrations of up to 15% should be achievable for plutonium alone, whereas the upper limit is 3% in the presence of fission products. The French continuous vitrification process appears to be particularly suitable for plutonium vitrification: its capacity is compatible with the required throughout, and the compact dimensions of the process equipment prevent a criticality hazard. Preprocessing of plutonium metal, to convert it to PuO{sub 2} or to a nitric acid solution, may prove advantageous or even necessary depending on whether a dry or wet process is adopted. The process may involve a single step (vitrification of Pu or PuO{sub 2} mixed with glass frit) or may include a prior calcination step - notably if the plutonium is to be incorporated into a fission product glass. It is important to weigh the advantages and drawbacks of all the possible options in terms of feasibility, safety and cost-effectiveness.

  11. Plutonium and americium separation from salts

    DOEpatents

    Hagan, Paul G.; Miner, Frend J.

    1976-01-01

    Salts or materials containing plutonium and americium are dissolved in hydrochloric acid, heated, and contacted with an alkali metal carbonate solution to precipitate plutonium and americium carbonates which are thereafter readily separable from the solution.

  12. Effect of aging at 1040 C (1900 F) on the ductility and structure of a tantalum alloy, T-111

    NASA Technical Reports Server (NTRS)

    Watson, G. K.; Stephens, J. R.

    1972-01-01

    The post-aging embrittlement of T-111 (tantalum - 8-percent tungsten - 2-percent hafnium) following exposure for up to about 10,000 hours at 1040 C in either vacuum or liquid lithium was investigated for sheet and tubing samples. This thermal aging was shown to greatly increase the sensitivity of T-111 to hydrogen embrittlement during subsequent room temperature specimen processing or testing. The hydrogen embrittlement problem can be avoided by preventing exposure to the T-111 to moisture during post-aging processing or testing. Aging at 1040 C also resulted in formation of HfO2 particles at grain boundaries, which may contribute to the observed embrittlement.

  13. PROCESS OF SEPARATING PLUTONIUM FROM URANIUM

    DOEpatents

    Brown, H.S.; Hill, O.F.

    1958-09-01

    A process is presented for recovering plutonium values from aqueous solutions. It comprises forming a uranous hydroxide precipitate in such a plutonium bearing solution, at a pH of at least 5. The plutonium values are precipitated with and carried by the uranium hydroxide. The carrier precipitate is then redissolved in acid solution and the pH is adjusted to about 2.5, causing precipitation of the uranous hydroxide but leaving the still soluble plutonium values in solution.

  14. Plutonium Proliferation: The Achilles Heel of Disarmament

    SciTech Connect

    Leventhal, Paul

    2001-02-07

    Plutonium is a byproduct of nuclear fission, and it is produced at the rate of about 70 metric tons a year in the world's nuclear power reactors. Concerns about civilian plutonium ran high in the 1970s and prompted enactment of the Nuclear Non-Proliferation Act of 1978 to give the United States a veto over separating plutonium from U.S.-supplied uranium fuel. Over the years, however, so-called reactor-grade plutonium has become the orphan issue of nuclear non-proliferation, largely as a consequence of pressures from plutonium-separating countries. The demise of the fast breeder reactor and the reluctance of utilities to introduce plutonium fuel in light-water reactors have resulted in large surpluses of civilian, weapons-usable plutonium, which now approach in size the 250 tons of military plutonium in the world. Yet reprocessing of spent fuel for recovery and use of plutonium proceeds apace outside the United States and threatens to overwhelm safeguards and security measures for keeping this material out of the hands of nations and terrorists for weapons. A number of historical and current developments are reviewed to demonstrate that plutonium commerce is undercutting efforts both to stop the spread of nuclear weapons and to work toward eliminating existing nuclear arsenals. These developments include the breakdown of U.S. anti-plutonium policy, the production of nuclear weapons by India with Atoms-for-Peace plutonium, the U.S.-Russian plan to introduce excess military plutonium as fuel in civilian power reactors, the failure to include civilian plutonium and bomb-grade uranium in the proposed Fissile Material Cutoff Treaty, and the perception of emerging proliferation threats as the rationale for development of a ballistic missile defense system. Finally, immobilization of separated plutonium in high-level waste is explored as a proliferation-resistant and disarmament-friendly solution for eliminating excess stocks of civilian and military plutonium.

  15. Evolution of the microstructure and magnetic properties of as-cast and melt spun Fe2NiAl alloy during aging

    NASA Astrophysics Data System (ADS)

    Menushenkov, V. P.; Gorshenkov, M. V.; Shchetinin, I. V.; Savchenko, A. G.; Savchenko, E. S.; Zhukov, D. G.

    2015-09-01

    Fe2NiAl-based alloy with the nominal composition Fe51.1Ni23.5Al23.7Si1.7 was prepared by casting and melt-spinning. Comparison of the phase composition, microstructure and magnetic properties of water-quenched bulk samples and melt spun ribbons after isothermal aging in the 500-900 °C range were carried out. TEM investigations of the decomposition of the solid solution into β- and β2 phases during cooling or quenching and subsequent aging have revealed different types of decomposition products. The optimal periodic modulated structure with coercive force Hc~700 Oe was observed after cooling of as-cast alloy at a critical rate. In this structure the paramagnetic β2 phase forms a continuous network that isolates elongated single domain ferromagnetic β particles. The water-quenched bulk samples and melt spun ribbons were characterized by zone structure with zones about 10 nm and 4 nm in size. The isothermal aging of quenched samples resulted in the formation of modulated microstructure dissimilar to those of the optimal state. The coarsening of ferromagnetic β particles as well as deterioration of the magnetic insulation of β particles occur in bulk samples after aging at Tag>700 °C that decreases Hc≤350 Oe. The dependence δM(H) was measured and negative values of δM(H) in the H=0-2000 Oe range indicate that magnetostatic interactions between the β particles are dominant. The melt spun ribbons were characterized by the presence of antiphase domain boundaries (APD) and discontinuous precipitation (DP) products at grain boundaries (GB). The cellular areas at GBs consisting of alternating lamellas of β‧- and β2‧ type phases were formed after aging the ribbons at Tag>500 °C. At Tag>700 °C the modulated structure formed inside grains and the wide intergranular double-layer of β and β2 phases develops by the coalescence of the primary DP products that decrease Hc≤250 Oe. MFM image of the magnetic structure correlated with the microstructure of the

  16. Heterogeneities and strain glass behavior: Role of nanoscale precipitates in low-temperature-aged Ti48.7Ni51.3 alloys

    NASA Astrophysics Data System (ADS)

    Ji, Yuanchao; Ding, Xiangdong; Lookman, Turab; Otsuka, Kazuhiro; Ren, Xiaobing

    2013-03-01

    A frozen short-range, strain-ordered state has been observed in several doped ferroelastic/martensitic alloys. The reported strain glass behavior has been attributed to atomic-scale point defects such as dopant atoms. We report here how nanoscale precipitates can also lead to such glassy behavior. Nanosized, randomly distributed Ti3Ni4-like precipitates, produced by aging/annealing at 473 K for 3 h, prohibit the B2 → B19' martensitic transition that occurs in a precipitate-free state. The strain glass transition is characterized by a mechanical susceptibility/modulus anomaly with Vogel-Fulcher type frequency-dependence, ergodicity-breaking, invariance in average structure and nanosized strain domains. Our work emphasizes that heterogeneities or in general disordering effects in ferroelastics will also give rise to signatures characteristic of strain glass behavior.

  17. Effects of isoconcentration surface threshold values on the characteristics of needle-shaped precipitates in atom probe tomography data from an aged Al-Mg-Si alloy.

    PubMed

    Aruga, Yasuhiro; Kozuka, Masaya

    2016-04-01

    Needle-shaped precipitates in an aged Al-0.62Mg-0.93Si (mass%) alloy were identified using a compositional threshold method, an isoconcentration surface, in atom probe tomography (APT). The influence of thresholds on the morphological and compositional characteristics of the precipitates was investigated. Utilizing optimum parameters for the concentration space, a reliable number density of the precipitates is obtained without dependence on the elemental concentration threshold in comparison with evaluation by transmission electron microscopy (TEM). It is suggested that careful selection of the concentration space in APT can lead to a reasonable average Mg/Si ratio for the precipitates. It was found that the maximum length and maximum diameter of the precipitates are affected by the elemental concentration threshold. Adjustment of the concentration threshold gives better agreement with the precipitate dimensions measured by TEM. PMID:26520787

  18. 49 CFR 175.704 - Plutonium shipments.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Regulations Applicable According to Classification of Material § 175.704 Plutonium shipments. Shipments of plutonium which are subject to 10 CFR 71.88(a)(4) must comply with the following: (a) Each package... 49 Transportation 2 2012-10-01 2012-10-01 false Plutonium shipments. 175.704 Section...

  19. 49 CFR 175.704 - Plutonium shipments.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Regulations Applicable According to Classification of Material § 175.704 Plutonium shipments. Shipments of plutonium which are subject to 10 CFR 71.88(a)(4) must comply with the following: (a) Each package... 49 Transportation 2 2014-10-01 2014-10-01 false Plutonium shipments. 175.704 Section...

  20. Plutonium immobilization -- Can loading. Revision 1

    SciTech Connect

    Kriikku, E.

    2000-03-13

    The Savannah River Site (SRS) will immobilize excess plutonium in the proposed Plutonium Immobilization Project (PIP). The PIP adds the excess plutonium to ceramic pucks, loads the pucks into cans, and places the cans into DWPF canisters. This paper discusses the PIP process steps, the can loading conceptual design, can loading equipment design, and can loading work completed.

  1. Plutonium Oxide Process Capability Work Plan

    SciTech Connect

    Meier, David E.; Tingey, Joel M.

    2014-02-28

    Pacific Northwest National Laboratory (PNNL) has been tasked to develop a Pilot-scale Plutonium-oxide Processing Unit (P3U) providing a flexible capability to produce 200g (Pu basis) samples of plutonium oxide using different chemical processes for use in identifying and validating nuclear forensics signatures associated with plutonium production. Materials produced can also be used as exercise and reference materials.

  2. 49 CFR 175.704 - Plutonium shipments.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Regulations Applicable According to Classification of Material § 175.704 Plutonium shipments. Shipments of plutonium which are subject to 10 CFR 71.88(a)(4) must comply with the following: (a) Each package... 49 Transportation 2 2013-10-01 2013-10-01 false Plutonium shipments. 175.704 Section...

  3. 49 CFR 175.704 - Plutonium shipments.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Regulations Applicable According to Classification of Material § 175.704 Plutonium shipments. Shipments of plutonium which are subject to 10 CFR 71.88(a)(4) must comply with the following: (a) Each package... 49 Transportation 2 2011-10-01 2011-10-01 false Plutonium shipments. 175.704 Section...

  4. 49 CFR 175.704 - Plutonium shipments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Regulations Applicable According to Classification of Material § 175.704 Plutonium shipments. Shipments of plutonium which are subject to 10 CFR 71.88(a)(4) must comply with the following: (a) Each package... 49 Transportation 2 2010-10-01 2010-10-01 false Plutonium shipments. 175.704 Section...

  5. Depressing effect of 0.1 wt.% Cr addition into Sn-9Zn solder alloy on the intermetallic growth with Cu substrate during isothermal aging

    SciTech Connect

    Hu Jin; Hu Anmin; Li Ming; Mao Dali

    2010-03-15

    In this paper, the effect of 0.1 wt.% Cr addition into Sn-9Zn lead-free solder alloys on the growth of intermetallic compound (IMC) with Cu substrate during soldering and subsequent isothermal aging was investigated. During soldering, it was found that 0.1 wt.% Cr addition did not contribute to forming the IMC, which was verified as the same phase structure as the IMC for Sn-9Zn/Cu. However, during solid-state isothermal aging, the IMC growth was remarkably depressed by 0.1 wt.% Cr addition in the Sn-9Zn solder, and this effect tended to be more prominent at higher aging temperature. The activation energy for IMC growth was determined as 21.2 kJ mol{sup -1} and 42.9 kJ mol{sup -1} for Sn-9Zn/Cu and Sn-9Zn-Cr/Cu, respectively. The reduced diffusion coefficient was confirmed for the 0.1Cr-containing solder/Cu. Energy-dispersive X-ray mapping and point analysis also showed ZnCr phase existing in solder matrix, which can reduce diffusion rate of Zn atoms.

  6. Technology and fabrication of plutonium-238 radionuclide heat sources

    NASA Astrophysics Data System (ADS)

    Malikh, Y. A.; Aldoshin, A. I.; Danilkin, E. A.

    1996-03-01

    This paper outlines a brief technical description of the facility for production of plutonium-238 and fabrication of Radionuclide Heat Sources (RHS) containing Pu-238. Technical capabilities of the RHS fabrication facility are presented. The results of development of the RHS design for sea application are discussed. RHS fuel pellet comprises the tantalum shell with an annular slot intended for release of radiogenic helium and the Pu-238 dioxide core with reinforcing elements inside which contact with the shell. RHS is a double encapsulation consisting of the inner ``power'' capsule and the outer corrosion-resistant capsule. The chromium-nickel-molybdenum XH65MB alloy which is equivalent to Hastelloy-C alloy has been selected as a material for both capsules. Upon expiration of working life, RHS design is capable of withstanding the internal pressure of radiogenic helium at 1073 K within 30 minutes and the external hydrostatic pressure of 100 MPa at normal temperature.

  7. Aging effects of diamond reinforced aluminium alloys submitted to deep space real conditions. Structural, chemical and electrical degradation

    NASA Astrophysics Data System (ADS)

    Korneli, Grigorov; Bouzekova-Penkova, Anna; Datcheva, Maria; Avdeev, George; Grushin, Valerii; Klimov, Stanislav

    2016-07-01

    An aluminium alloy (Al-Cu-Zn-Mg) reinforced with ultra-dispersed diamond powder and tungsten (W), has been prepared in form of 7 cm bars and 4 mm diameter. One part of them stayed 2 years on satellite exposed to outer space, where the Sun activity and the background radiation were monitored. After satellite return both batches has been studied. Structural test, mainly micro-hardness together with detailed X-rays analyses was performed. The satellite makes a tour around the Earth each two hours, the temperature difference being circa 300oC. The micro-hardness being measured with Agilent G200 nano-indentor shows a significant drop of 25%. The XRD patterns are consistent with the previous results, states defects incorporation, and crystalline cells deterioration.

  8. AMS of the Minor Plutonium Isotopes.

    PubMed

    Steier, P; Hrnecek, E; Priller, A; Quinto, F; Srncik, M; Wallner, A; Wallner, G; Winkler, S

    2013-01-01

    VERA, the Vienna Environmental Research Accelerator, is especially equipped for the measurement of actinides, and performs a growing number of measurements on environmental samples. While AMS is not the optimum method for each particular plutonium isotope, the possibility to measure (239)Pu, (240)Pu, (241)Pu, (242)Pu and (244)Pu on the same AMS sputter target is a great simplification. We have obtained a first result on the global fallout value of (244)Pu/(239)Pu = (5.7 ± 1.0) × 10(-5) based on soil samples from Salzburg prefecture, Austria. Furthermore, we suggest using the (242)Pu/(240)Pu ratio as an estimate of the initial (241)Pu/(239)Pu ratio, which allows dating of the time of irradiation based solely on Pu isotopes. We have checked the validity of this estimate using literature data, simulations, and environmental samples from soil from the Salzburg prefecture (Austria), from the shut down Garigliano Nuclear Power Plant (Sessa Aurunca, Italy) and from the Irish Sea near the Sellafield nuclear facility. The maximum deviation of the estimated dates from the expected ages is 6 years, while relative dating of material from the same source seems to be possible with a precision of less than 2 years. Additional information carried by the minor plutonium isotopes may allow further improvements of the precision of the method. PMID:23565016

  9. AMS of the Minor Plutonium Isotopes

    PubMed Central

    Steier, P.; Hrnecek, E.; Priller, A.; Quinto, F.; Srncik, M.; Wallner, A.; Wallner, G.; Winkler, S.

    2013-01-01

    VERA, the Vienna Environmental Research Accelerator, is especially equipped for the measurement of actinides, and performs a growing number of measurements on environmental samples. While AMS is not the optimum method for each particular plutonium isotope, the possibility to measure 239Pu, 240Pu, 241Pu, 242Pu and 244Pu on the same AMS sputter target is a great simplification. We have obtained a first result on the global fallout value of 244Pu/239Pu = (5.7 ± 1.0) × 10−5 based on soil samples from Salzburg prefecture, Austria. Furthermore, we suggest using the 242Pu/240Pu ratio as an estimate of the initial 241Pu/239Pu ratio, which allows dating of the time of irradiation based solely on Pu isotopes. We have checked the validity of this estimate using literature data, simulations, and environmental samples from soil from the Salzburg prefecture (Austria), from the shut down Garigliano Nuclear Power Plant (Sessa Aurunca, Italy) and from the Irish Sea near the Sellafield nuclear facility. The maximum deviation of the estimated dates from the expected ages is 6 years, while relative dating of material from the same source seems to be possible with a precision of less than 2 years. Additional information carried by the minor plutonium isotopes may allow further improvements of the precision of the method. PMID:23565016

  10. Plutonium stabilization and packaging system

    SciTech Connect

    1996-05-01

    This document describes the functional design of the Plutonium Stabilization and Packaging System (Pu SPS). The objective of this system is to stabilize and package plutonium metals and oxides of greater than 50% wt, as well as other selected isotopes, in accordance with the requirements of the DOE standard for safe storage of these materials for 50 years. This system will support completion of stabilization and packaging campaigns of the inventory at a number of affected sites before the year 2002. The package will be standard for all sites and will provide a minimum of two uncontaminated, organics free confinement barriers for the packaged material.

  11. Some neutron and gamma radiation characteristics of plutonium cermet fuel for isotopic power sources

    NASA Technical Reports Server (NTRS)

    Neff, R. A.; Anderson, M. E.; Campbell, A. R.; Haas, F. X.

    1972-01-01

    Gamma and neutron measurements on various types of plutonium sources are presented in order to show the effects of O-17, O-18 F-19, Pu-236, age of the fuel, and size of the source on the gamma and neutron spectra. Analysis of the radiation measurements shows that fluorine is the main contributor to the neutron yields from present plutonium-molybdenum cermet fuel, while both fluorine and Pu-236 daughters contribute significantly to the gamma ray intensities.

  12. Plutonium-244 fission tracks - Evidence in a lunar rock 3.95 billion years old.

    NASA Technical Reports Server (NTRS)

    Hutcheon, I. D.; Price, P. B.

    1972-01-01

    Tracks attributed to the spontaneous fission of plutonium-244 and of uranium-238 were detected in a large whitlockite crystal in the lunar breccia 14321 from the Fra Mauro formation. For a track-retention age of 3.95 b.y., the number of plutonium tracks relative to the number of uranium tracks is 0.51 plus or minus 0.15, provided that the rock was not heavily neutron-irradiated 3.95 b.y. ago.

  13. Plutonium immobilization feed batching system concept report

    SciTech Connect

    Erickson, S.

    2000-07-19

    The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with high level waste glass for permanent storage. Feed batching is one of the first process steps involved with first stage plutonium immobilization. It will blend plutonium oxide powder before it is combined with other materials to make pucks. This report discusses the Plutonium Immobilization feed batching process preliminary concept, batch splitting concepts, and includes a process block diagram, concept descriptions, a preliminary equipment list, and feed batching development areas.

  14. Method of separating thorium from plutonium

    DOEpatents

    Clifton, D.G.; Blum, T.W.

    A method of chemically separating plutonium from thorium is claimed. Plutonium and thorium to be separated are dissolved in an aqueous feed solution, preferably as the nitrate salts. The feed solution is acidified and sodium nitrite is added to the solution to adjust the valence of the plutonium to the +4 state. A chloride salt, preferably sodium chloride, is then added to the solution to induce formation of an anionic plutonium chloride complex. The anionic plutonium chloride complex and the thorium in solution are then separated by ion exchange on a strong base anion exchange column.

  15. Method of separating thorium from plutonium

    DOEpatents

    Clifton, D.G.; Blum, T.W.

    1984-07-10

    A method is described for chemically separating plutonium from thorium. Plutonium and thorium to be separated are dissolved in an aqueous feed solution, preferably as the nitrate salts. The feed solution is acidified and sodium nitrite is added to the solution to adjust the valence of the plutonium to the +4 state. A chloride salt, preferably sodium chloride, is then added to the solution to induce formation of an anionic plutonium chloride complex. The anionic plutonium chloride complex and the thorium in solution are then separated by ion exchange on a strong base anion exchange column.

  16. Method of separating thorium from plutonium

    DOEpatents

    Clifton, David G.; Blum, Thomas W.

    1984-01-01

    A method of chemically separating plutonium from thorium. Plutonium and thorium to be separated are dissolved in an aqueous feed solution, preferably as the nitrate salts. The feed solution is acidified and sodium nitrite is added to the solution to adjust the valence of the plutonium to the +4 state. A chloride salt, preferably sodium chloride, is then added to the solution to induce formation of an anionic plutonium chloride complex. The anionic plutonium chloride complex and the thorium in solution are then separated by ion exchange on a strong base anion exchange column.

  17. Plutonium Speciation, Solubilization and Migration in Soils

    SciTech Connect

    Neu, M.; Runde, W.

    1999-06-01

    This report summarizes research completed in the first half of a three-year project. As outlined in the authors' proposal they are focusing on (1) characterizing the plutonium at an actinide contaminated site, RFETS, including determining the origin, dispersion, and speciation of the plutonium, (2) studying environmentally important plutonium complexes, primarily hydroxides and carbonates, and (3) examining the interactions of plutonium species with manganese minerals. In the first year the authors focused on site based studies. This year they continue to characterize samples from the RFETS, study the formation and structural and spectroscopic features of environmentally relevant Pu species, and begin modeling the environmental behavior of plutonium.

  18. PROCESS FOR SEPARATING PLUTONIUM FROM IMPURITIES

    DOEpatents

    Wahl, A.C.

    1957-11-12

    A method is described for separating plutonium from aqueous solutions containing uranium. It has been found that if the plutonium is reduced to its 3+ valence state, and the uranium present is left in its higher valence state, then the differences in solubility between certain salts (e.g., oxalates) of the trivalent plutonium and the hexavalent uranium can be used to separate the metals. This selective reduction of plutonium is accomplished by adding iodide ion to the solution, since iodide possesses an oxidation potential sufficient to reduce plutonium but not sufficient to reduce uranium.

  19. Plutonium inventory characterization technical evaluation report

    SciTech Connect

    Wittman, G.R., Westinghouse Hanford

    1996-07-10

    This is a technical report on the data, gathered to date, under WHC- SD-CP-TP-086, Rev. 1, on the integrity of the food pack cans currently being used to store plutonium or plutonium compounds at the Plutonium Finishing Plant. Workplan PFP-96-VO-009, `Inspection of Special Nuclear Material Using X-ray`, was used to gather data on material and containment conditions using real time radiography. Some of those images are included herein. A matrix found in the `Plutonium Inventory Characterization Implementation Plan` was used to categorize different plutonium items based upon the type of material being stored and the life expectancy of the containers.

  20. PLUTONIUM COMPOUNDS AND PROCESS FOR THEIR PREPARATION

    DOEpatents

    Wolter, F.J.; Diehl, H.C. Jr.

    1958-01-01

    This patent relates to certain new compounds of plutonium, and to the utilization of these compounds to effect purification or separation of the plutonium. The compounds are organic chelate compounds consisting of tetravalent plutonium together with a di(salicylal) alkylenediimine. These chelates are soluble in various organic solvents, but not in water. Use is made of this property in extracting the plutonium by contacting an aqueous solution thereof with an organic solution of the diimine. The plutonium is chelated, extracted and effectively separated from any impurities accompaying it in the aqueous phase.

  1. Electrorefining process and apparatus for recovery of uranium and a mixture of uranium and plutonium from spent fuels

    DOEpatents

    Ackerman, John P.; Miller, William E.

    1989-01-01

    An electrorefining process and apparatus for the recovery of uranium and a mixture of uranium and plutonium from spent fuel using an electrolytic cell having a lower molten cadmium pool containing spent nuclear fuel, an intermediate electrolyte pool, an anode basket containing spent fuel, and two cathodes, the first cathode composed of either a solid alloy or molten cadmium and the second cathode composed of molten cadmium. Using this cell, additional amounts of uranium and plutonium from the anode basket are dissolved in the lower molten cadmium pool, and then substantially pure uranium is electrolytically transported and deposited on the first alloy or molten cadmium cathode. Subsequently, a mixture of uranium and plutonium is electrotransported and deposited on the second molten cadmium cathode.

  2. The First Weighing of Plutonium

    DOE R&D Accomplishments Database

    Seaborg, Glenn T.

    1967-09-10

    Recollections and reminiscences at the 25th Anniversary of the First Weighing of Plutonium, Chicago, IL, September 10, 1967, tell an important part of the story of this fascinating new element that is destined to play an increasingly significant role in the future of man.

  3. Safe disposal of surplus plutonium

    NASA Astrophysics Data System (ADS)

    Gong, W. L.; Naz, S.; Lutze, W.; Busch, R.; Prinja, A.; Stoll, W.

    2001-06-01

    About 150 tons of weapons grade and weapons usable plutonium (metal, oxide, and in residues) have been declared surplus in the USA and Russia. Both countries plan to convert the metal and oxide into mixed oxide fuel for nuclear power reactors. Russia has not yet decided what to do with the residues. The US will convert residues into a ceramic, which will then be over-poured with highly radioactive borosilicate glass. The radioactive glass is meant to provide a deterrent to recovery of plutonium, as required by a US standard. Here we show a waste form for plutonium residues, zirconia/boron carbide (ZrO 2/B 4C), with an unprecedented combination of properties: a single, radiation-resistant, and chemically durable phase contains the residues; billion-year-old natural analogs are available; and criticality safety is given under all conceivable disposal conditions. ZrO 2/B 4C can be disposed of directly, without further processing, making it attractive to all countries facing the task of plutonium disposal. The US standard for protection against recovery can be met by disposal of the waste form together with used reactor fuel.

  4. Plutonium waste incineration using pyrohydrolysis

    SciTech Connect

    Meyer, M.L.

    1991-01-01

    Waste generated by Savannah River Site (SRS) plutonium operations includes a contaminated organic waste stream. A conventional method for disposing of the organic waste stream and recovering the nuclear material is by incineration. When the organic material is burned, the plutonium remains in the incinerator ash. Plutonium recovery from incinerator ash is highly dependent on the maximum temperature to which the oxide is exposed. Recovery via acid leaching is reduced for a high fired ash (>800{degree}C), while plutonium oxides fired at lower decomposition temperatures (400--800{degrees}C) are more soluble at any given acid concentration. To determine the feasibility of using a lower temperature process, tests were conducted using an electrically heated, controlled-air incinerator. Nine nonradioactive, solid, waste materials were batch-fed and processed in a top-heated cylindrical furnace. Waste material processing was completed using a 19-liter batch over a nominal 8-hour cycle. A processing cycle consisted of 1 hour for heating, 4 hours for reacting, and 3 hours for chamber cooling. The water gas shift reaction was used to hydrolyze waste materials in an atmosphere of 336% steam and 4.4% oxygen. Throughput ranged from 0.14 to 0.27 kg/hr depending on the variability in the waste material composition and density.

  5. Plutonium waste incineration using pyrohydrolysis

    SciTech Connect

    Meyer, M.L.

    1991-12-31

    Waste generated by Savannah River Site (SRS) plutonium operations includes a contaminated organic waste stream. A conventional method for disposing of the organic waste stream and recovering the nuclear material is by incineration. When the organic material is burned, the plutonium remains in the incinerator ash. Plutonium recovery from incinerator ash is highly dependent on the maximum temperature to which the oxide is exposed. Recovery via acid leaching is reduced for a high fired ash (>800{degree}C), while plutonium oxides fired at lower decomposition temperatures (400--800{degrees}C) are more soluble at any given acid concentration. To determine the feasibility of using a lower temperature process, tests were conducted using an electrically heated, controlled-air incinerator. Nine nonradioactive, solid, waste materials were batch-fed and processed in a top-heated cylindrical furnace. Waste material processing was completed using a 19-liter batch over a nominal 8-hour cycle. A processing cycle consisted of 1 hour for heating, 4 hours for reacting, and 3 hours for chamber cooling. The water gas shift reaction was used to hydrolyze waste materials in an atmosphere of 336% steam and 4.4% oxygen. Throughput ranged from 0.14 to 0.27 kg/hr depending on the variability in the waste material composition and density.

  6. Plutonium Recycle: The Fateful Step

    ERIC Educational Resources Information Center

    Speth, J. Gustave; And Others

    1974-01-01

    Calls attention to the fact that if the Atomic Energy Commission proceeds with its plans to authorize the nuclear power industry to use plutonium as a fuel in commercial nuclear reactors around the country, this will result in a dramatic escalation in the risks posed by nuclear power. (PEB)

  7. Non-classical nuclei and growth kinetics of Cr precipitates in FeCr alloys during ageing

    SciTech Connect

    Li, Yulan; Hu, Shenyang Y.; Zhang, Lei; Sun, Xin

    2014-01-10

    In this manuscript, we quantitatively calculated the thermodynamic properties of critical nuclei of Cr precipitates in FeCr alloys. The concentration profiles of the critical nuclei and nucleation energy barriers were predicted by the constrained shrinking dimer dynamics (CSDD) method. It is found that Cr concentration distribution in the critical nuclei strongly depend on the overall Cr concentration as well as temperature. The critical nuclei are non-classical because the concentration in the nuclei is smaller than the thermodynamic equilibrium value. These results are in agreement with atomic probe observation. The growth kinetics of both classical and non-classical nuclei was investigated by the phase field approach. The simulations of critical nucleus evolution showed a number of interesting phenomena: 1) a critical classical nucleus first shrinks toward its non-classical nucleus and then grows; 2) a non-classical nucleus has much slower growth kinetics at its earlier growth stage compared to the diffusion-controlled growth kinetics. 3) a critical classical nucleus grows faster at the earlier growth stage than the non-classical nucleus. All of these results demonstrate that it is critical to introduce the correct critical nuclei in order to correctly capture the kinetics of precipitation.

  8. Non-classical nuclei and growth kinetics of Cr precipitates in FeCr alloys during ageing

    NASA Astrophysics Data System (ADS)

    Li, Yulan; Hu, Shenyang; Zhang, Lei; Sun, Xin

    2014-03-01

    In this manuscript, we have quantitatively calculated the thermodynamic properties of the critical nuclei of Cr precipitates in FeCr alloys. The concentration profiles of the critical nuclei and nucleation energy barriers were predicted by the constrained shrinking dimer dynamics method. It is found that Cr concentration distribution in the critical nuclei strongly depends on the overall Cr concentration as well as on the temperature. The critical nuclei are non-classical because the concentration in the nuclei is smaller than the thermodynamic equilibrium value. These results are in agreement with atomic probe observation. The growth kinetics of both classical and non-classical nuclei was investigated by the phase-field approach. The simulations of critical nucleus evolution showed a number of interesting phenomena: (1) a critical classical nucleus first shrinks toward its non-classical nucleus and then grows; (2) a non-classical nucleus has much slower growth kinetics at its earlier growth stage compared to the diffusion-controlled growth kinetics and (3) a critical classical nucleus grows faster at the earlier growth stage than does a non-classical nucleus. All of these results demonstrate that it is critical to introduce the correct critical nuclei in order to correctly capture the kinetics of precipitation.

  9. Slow Aging Dynamics and Avalanches in a Gold-Cadmium Alloy Investigated by X-Ray Photon Correlation Spectroscopy

    SciTech Connect

    Mueller, L.; Waldorf, M.; Klemradt, U.; Gutt, C.; Gruebel, G.; Madsen, A.; Finlayson, T. R.

    2011-09-02

    Results of a x-ray photon correlation spectroscopy experiment on the very weakly first order martensitic transformation of a Au{sub 50.5}Cd{sub 49.5} single crystal are presented. Slow non-equilibrium-dynamics are observed in a narrow temperature interval in the direct vicinity of the otherwise athermal phase transformation. These dynamics are associated with the martensite-aging effect. The dynamical aging is accompanied by an avalanchelike behavior which is identified with an incubation-time phenomenon.

  10. Aging characteristics of electron beam and gas tungsten arc fusion zones of Al-Cu-Li alloy 2090

    SciTech Connect

    Sunwoo, A.J. . Center for Advanced Materials); Morris, J.W. Jr. . Dept of Materials Science and Engineering)

    1991-04-01

    A transmission electron microscopy (TEM) investigation of the electron beam (EB) and gas tungsten arc (GTA) fusion zones of 2090 indicates that in both the as-welded and aged conditions, the EB and GTA fusion zones lack the volume fraction and the homogeneity of strengthening precipitates found in the base metal. In the underaged and peak-aged conditions, the [delta][prime] phase is the primary strengthener, the volume fraction of T[sub 1] present being too low to be effective. The T[sub 1] precipitates are found either in the vicinity of other inclusions or at the dendrite boundaries. As the strength increases with postweld aging, the elongation decreased to 1%. The presence of the boundary phases and Cu- and Cl-containing inclusions at the boundaries leads to poor elongation. The joint efficiencies of the peak-aged EB and GTA weldments (EBWs and GTAWs, respectively) are 75 and 55% at 293 K and 75 and 50% at 77 K, respectively. Both EBWs and GTAWs have relatively low elongations.

  11. The radiological hazard of plutonium isotopes and specific plutonium mixtures

    SciTech Connect

    Heindel, G.; Clow, J.; Inkret, W.; Miller, G.

    1995-11-01

    The US Department of Energy defines the hazard categories of its nuclear facilities based upon the potential for accidents to have significant effects on specific populations and the environment. In this report, the authors consider the time dependence of hazard category 2 (significant on-site effects) for facilities with inventories of plutonium isotopes and specific weapons-grade and heat-source mixtures of plutonium isotopes. The authors also define relative hazard as the reciprocal of the hazard category 2 threshold value and determine its time dependence. The time dependence of both hazard category 2 thresholds and relative hazards are determined and plotted for 10,000 years to provide useful information for planning long-term storage or disposal facilities.

  12. Ultrasonic sensor signals and optimum path forest classifier for the microstructural characterization of thermally-aged inconel 625 alloy.

    PubMed

    de Albuquerque, Victor Hugo C; Barbosa, Cleisson V; Silva, Cleiton C; Moura, Elineudo P; Filho, Pedro P Rebouças; Papa, João P; Tavares, João Manuel R S

    2015-01-01

    Secondary phases, such as laves and carbides, are formed during the final solidification stages of nickel-based superalloy coatings deposited during the gas tungsten arc welding cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the γ'' and δ phases. This work presents an evaluation of the powerful optimum path forest (OPF) classifier configured with six distance functions to classify background echo and backscattered ultrasonic signals from samples of the inconel 625 superalloy thermally aged at 650 and 950 °C for 10, 100 and 200 h. The background echo and backscattered ultrasonic signals were acquired using transducers with frequencies of 4 and 5 MHz. The potentiality of ultrasonic sensor signals combined with the OPF to characterize the microstructures of an inconel 625 thermally aged and in the as-welded condition were confirmed by the results. The experimental results revealed that the OPF classifier is sufficiently fast (classification total time of 0.316 ms) and accurate (accuracy of 88.75%" and harmonic mean of 89.52) for the application proposed. PMID:26024416

  13. Ultrasonic Sensor Signals and Optimum Path Forest Classifier for the Microstructural Characterization of Thermally-Aged Inconel 625 Alloy

    PubMed Central

    de Albuquerque, Victor Hugo C.; Barbosa, Cleisson V.; Silva, Cleiton C.; Moura, Elineudo P.; Rebouças Filho, Pedro P.; Papa, João P.; Tavares, João Manuel R. S.

    2015-01-01

    Secondary phases, such as laves and carbides, are formed during the final solidification stages of nickel-based superalloy coatings deposited during the gas tungsten arc welding cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the γ” and δ phases. This work presents an evaluation of the powerful optimum path forest (OPF) classifier configured with six distance functions to classify background echo and backscattered ultrasonic signals from samples of the inconel 625 superalloy thermally aged at 650 and 950 °C for 10, 100 and 200 h. The background echo and backscattered ultrasonic signals were acquired using transducers with frequencies of 4 and 5 MHz. The potentiality of ultrasonic sensor signals combined with the OPF to characterize the microstructures of an inconel 625 thermally aged and in the as-welded condition were confirmed by the results. The experimental results revealed that the OPF classifier is sufficiently fast (classification total time of 0.316 ms) and accurate (accuracy of 88.75% and harmonic mean of 89.52) for the application proposed. PMID:26024416

  14. Evaluation of TASTEX task H: measurement of plutonium isotopic abundances by gamma-ray spectrometry

    SciTech Connect

    Gunnink, R.; Prindle, A.L.; Asakura, Y.; Masui, J.; Ishiguro, N.; Kawasaki, A.; Kataoka, S.

    1981-10-01

    This report describes a computer-based gamma spectrometer system that was developed for measuring isotopic and total plutonium concentrations in nitric acid solutions. The system was installed at the Tokai reprocessing plant where it is undergoing testing and evaluation as part of the Tokai Advanced Safeguards Exercise (TASTEX). Objectives of TASTEX Task H, High-Resolution Gamma Spectrometer for Plutonium Isotopic Analysis, the methods and equipment used, the installation and calibration of the system, and the measurements obtained from several reprocessing campaigns are discussed and described. In general, we find that measurements for gamma spectroscopy agree well with those of mass spectrometry and of other chemical analysis. The system measures both freshly processed plutonium from the product accountability tank and aged plutonium solutions from storage tanks. 14 figures, 15 tables.

  15. Plutonium Immobilization Can Loading Concepts

    SciTech Connect

    Kriikku, E.; Ward, C.; Stokes, M.; Randall, B.; Steed, J.; Jones, R.; Hamilton, L.; Rogers, L.; Fiscus, J.; Dyches, G.

    1998-05-01

    The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. This report discusses five can loading conceptual designs and the lists the advantages and disadvantages for each concept. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas. The can loading welder and cutter are very similar to the existing Savannah River Site (SRS) FB-Line bagless transfer welder and cutter and thus they are a low priority development item.

  16. Plutonium Immobilization Project -- Can loading

    SciTech Connect

    Kriikku, E.

    2000-01-18

    The Savannah River Site (SRS) will immobilize excess plutonium in the proposed Plutonium Immobilization Project (PIP). The PIP scope includes unloading transportation containers, preparing the feed streams, converting the metal feed to an oxide, adding the ceramic precursors, pressing the pucks, inspecting pucks, and sintering pucks. The PIP scope also includes loading the pucks into metal cans, sealing the cans, inspecting the cans, loading the cans into magazines, loading magazines into Defense Waste Processing Facility (DWPF) canisters, and transporting the canisters to the DWPF. The DWPF fills the canister with a mixture of high level radioactive waste and glass for permanent storage. Due to the radiation, remote equipment must perform PIP operations in a contained environment.

  17. Plutonium Immobilization Project Baseline Formulation

    SciTech Connect

    Ebbinghaus, B.

    1999-02-01

    A key milestone for the Immobilization Project (AOP Milestone 3.2a) in Fiscal Year 1998 (FY98) is the definition of the baseline composition or formulation for the plutonium ceramic form. The baseline formulation for the plutonium ceramic product must be finalized before the repository- and plant-related process specifications can be determined. The baseline formulation that is currently specified is given in Table 1.1. In addition to the baseline formulation specification, this report provides specifications for two alternative formulations, related compositional specifications (e.g., precursor compositions and mixing recipes), and other preliminary form and process specifications that are linked to the baseline formulation. The preliminary specifications, when finalized, are not expected to vary tremendously from the preliminary values given.

  18. Provenance of unknown plutonium material.

    PubMed

    Nicolaou, G

    2008-10-01

    The determination of the provenance of 'unknown' plutonium material is demonstrated through a simulation study based on an isotopic fingerprinting approach. Plutonium of known provenance was considered as the 'unknown' nuclear material in order to evaluate the potential of the approach and verify its predictive capabilities. Factor analysis was used to compare the Pu isotopic composition of the 'unknown' material with Pu isotopic compositions simulating well known spent fuels from a range of commercial nuclear power stations. The provenance of the 'unknown material' is assigned to the commercial fuel with which exhibits the highest degree of similarity with respect to the Pu composition. The approach appears promising since it accurately predicted the provenance of the one 'unknown' sample considered; nevertheless, the approach is still at the development stage. Important challenging issues related to the simulation uncertainties and its testing on real laboratory samples have to be explored prior to evaluating the potential of the approach. PMID:18639370

  19. Biokinetics of Plutonium in Nonhuman Primates.

    PubMed

    Poudel, Deepesh; Guilmette, Raymond A; Gesell, Thomas F; Harris, Jason T; Brey, Richard R

    2016-10-01

    A major source of data on metabolism, excretion and retention of plutonium comes from experimental animal studies. Although old world monkeys are one of the closest living relatives to humans, certain physiological differences do exist between these nonhuman primates and humans. The objective of this paper was to describe the metabolism of plutonium in nonhuman primates using the bioassay and retention data obtained from macaque monkeys injected with plutonium citrate. A biokinetic model for nonhuman primates was developed by adapting the basic model structure and adapting the transfer rates described for metabolism of plutonium in adult humans. Significant changes to the parameters were necessary to explain the shorter retention of plutonium in liver and skeleton of the nonhuman primates, differences in liver to bone partitioning ratio, and significantly higher excretion of plutonium in feces compared to that in humans. PMID:27575347

  20. SEPARATION OF PLUTONIUM HYDROXIDE FROM BISMUTH HYDROXIDE

    DOEpatents

    Watt, G.W.

    1958-08-19

    An tmproved method is described for separating plutonium hydroxide from bismuth hydroxide. The end product of the bismuth phosphate processes for the separation amd concentration of plutonium is a inixture of bismuth hydroxide amd plutonium hydroxide. It has been found that these compounds can be advantageously separated by treatment with a reducing agent having a potential sufficient to reduce bismuth hydroxide to metalltc bisinuth but not sufficient to reduce the plutonium present. The resulting mixture of metallic bismuth and plutonium hydroxide can then be separated by treatment with a material which will dissolve plutonium hydroxide but not metallic bismuth. Sodiunn stannite is mentioned as a preferred reducing agent, and dilute nitric acid may be used as the separatory solvent.

  1. Air transport of plutonium metal: content expansion initiative for the plutonium air transportable (PAT01) packaging

    SciTech Connect

    Caviness, Michael L; Mann, Paul T

    2010-01-01

    The National Nuclear Security Administration (NNSA) has submitted an application to the Nuclear Regulatory Commission (NRC) for the air shipment of plutonium metal within the Plutonium Air Transportable (PAT-1) packaging. The PAT-1 packaging is currently authorized for the air transport of plutonium oxide in solid form only. The INMM presentation will provide a limited overview of the scope of the plutonium metal initiative and provide a status of the NNSA application to the NRC.

  2. Air transport of plutonium metal : content expansion initiative for the Plutonium Air Transportable (PAT-1) packaging.

    SciTech Connect

    Mann, Paul T.; Caviness, Michael L.; Yoshimura, Richard Hiroyuki

    2010-06-01

    The National Nuclear Security Administration (NNSA) has submitted an application to the Nuclear Regulatory Commission (NRC) for the air shipment of plutonium metal within the Plutonium Air Transportable (PAT-1) packaging. The PAT-1 packaging is currently authorized for the air transport of plutonium oxide in solid form only. The INMM presentation will provide a limited overview of the scope of the plutonium metal initiative and provide a status of the NNSA application to the NRC.

  3. PLUTONIUM METAL: OXIDATION CONSIDERATIONS AND APPROACH

    SciTech Connect

    Estochen, E.

    2013-03-20

    Plutonium is arguably the most unique of all metals when considered in the combined context of metallurgical, chemical, and nuclear behavior. Much of the research in understanding behavior and characteristics of plutonium materials has its genesis in work associated with nuclear weapons systems. However, with the advent of applications in fuel materials, the focus in plutonium science has been more towards nuclear fuel applications, as well as long term storage and disposition. The focus of discussion included herein is related to preparing plutonium materials to meet goals consistent with non-proliferation. More specifically, the emphasis is on the treatment of legacy plutonium, in primarily metallic form, and safe handling, packaging, and transport to meet non-proliferation goals of safe/secure storage. Elevated temperature oxidation of plutonium metal is the treatment of choice, due to extensive experiential data related to the method, as the oxide form of plutonium is one of only a few compounds that is relatively simple to produce, and stable over a large temperature range. Despite the simplicity of the steps required to oxidize plutonium metal, it is important to understand the behavior of plutonium to ensure that oxidation is conducted in a safe and effective manner. It is important to understand the effect of changes in environmental variables on the oxidation characteristics of plutonium. The primary purpose of this report is to present a brief summary of information related to plutonium metal attributes, behavior, methods for conversion to oxide, and the ancillary considerations related to processing and facility safety. The information provided is based on data available in the public domain and from experience in oxidation of such materials at various facilities in the United States. The report is provided as a general reference for implementation of a simple and safe plutonium metal oxidation technique.

  4. PROCESS OF SEPARATING PLUTONIUM VALUES BY ELECTRODEPOSITION

    DOEpatents

    Whal, A.C.

    1958-04-15

    A process is described of separating plutonium values from an aqueous solution by electrodeposition. The process consists of subjecting an aqueous 0.1 to 1.0 N nitric acid solution containing plutonium ions to electrolysis between inert metallic electrodes. A current density of one milliampere io one ampere per square centimeter of cathode surface and a temperature between 10 and 60 d C are maintained. Plutonium is electrodeposited on the cathode surface and recovered.

  5. PROCESS FOR THE RECOVERY OF PLUTONIUM

    DOEpatents

    Potratz, H.A.

    1958-12-16

    A process for the separation of plutonium from uranlum and other associated radioactlve fission products ls descrlbed conslstlng of contacting an acid solution containing plutonium in the tetravalent state and uranium in the hexavalent state with enough ammonium carbonate to form an alkaline solution, adding cupferron to selectlvely form plutonlum cupferrlde, then recoverlng the plutonium cupferride by extraction with a water lmmiscible organic solvent such as chloroform.

  6. WET METHOD OF PREPARING PLUTONIUM TRIBROMIDE

    DOEpatents

    Davidson, N.R.; Hyde, E.K.

    1958-11-11

    S> The preparation of anhydrous plutonium tribromide from an aqueous acid solution of plutonium tetrabromide is described, consisting of adding a water-soluble volatile bromide to the tetrabromide to provide additional bromide ions sufficient to furnish an oxidation-reduction potential substantially more positive than --0.966 volt, evaporating the resultant plutonium tribromides to dryness in the presence of HBr, and dehydrating at an elevated temperature also in the presence of HBr.

  7. PRECIPITATION METHOD FOR THE SEPARATION OF PLUTONIUM AND RARE EARTHS

    DOEpatents

    Thompson, S.G.

    1960-04-26

    A method of purifying plutonium is given. Tetravalent plutonium is precipitated with thorium pyrophosphate, the plutonium is oxidized to the tetravalent state, and then impurities are precipitated with thorium pyrophosphate.

  8. Intrinsic Nanoscience of δ Pu-Ga Alloys: Local Structure and Speciation, Collective Behavior, Nanoscale Heterogeneity, and Aging Mechanisms

    SciTech Connect

    Conradson, Steven D.; Bock, Nicolas; Castro, Julio M.; Conradson, Dylan R.; Cox, Lawrence E.; Dmowski, Wojtek; Dooley, David E.; Egami, Takeshi; Espinosa-Faller, Francisco J.; Freibert, Franz J.; Garcia-Adeva, Angel J.; Hess, Nancy J.; Holmstrom, Erik; Howell, Rafael C.; Katz, Barbara A.; Lashley, Jason C.; Martinez, Raymond J.; Moore, David P.; Morales, Luis A.; Olivas, J David; Pereyra, Ramiro A.; Ramos, Michael; Terry, Jeff H.; Villella, Phillip M.

    2014-04-24

    Because diffraction measurements are sensitive only to the long range average arrangement of the atoms in the coherent portion of a crystal, complementary local structure measurements are required for a complete understanding of the structure of a complex material. This is particularly an issue in solid solutions where even random distributions of a solute will result in nanometer-scale fluctuations in the local composition. The structure will be further complicated if collective and cooperative phenomena organize the solute distribution via longer range interactions between non-bonded solute sites. If the solute affects the phase stability then the question is raised of whether the atoms in domains with local compositions outside the limits of the bulk phase will rearrange into the structure stable for that composition and temperature or if the resulting stress would prevent such a local phase transition. If the former, then phase separated, heterogeneous structures at or below the diffraction limit will form. This nanometerscale competition between the phase transition and the epitaxial mismatch – exacerbated by the added strain if the transition involves a volume change – raises the potential for the formation of novel structures that do not occur in bulk material, e.g., fcc Fe. This coupling over multiple scales between inhomogeneity ordering, elastic forces, phase competition, and texture in the form of coexisting structures is a hallmark of martensites, a class of complex materials that includes δ-stabilized PuGa and that often exhibit correlated atomic and electronic properties. The enigmatic and extreme nature of Pu is consistent with its exhibiting unusual structural behavior of this type, including nanoscale heterogeneity in δ-stabilized PuGa and its enhanced homogeneity on aging that has been suggested based on earlier X-ray Absorption Fine Structure (XAFS) spectroscopy and x-ray pair distribution function (pdf) measurements. Measurements on a

  9. PLUTONIUM-CUPFERRON COMPLEX AND METHOD OF REMOVING PLUTONIUM FROM SOLUTION

    DOEpatents

    Potratz, H.A.

    1959-01-13

    A method is presented for separating plutonium from fission products present in solutions of neutronirradiated uranium. The process consists in treating such acidic solutions with cupferron so that the cupferron reacts with the plutonium present to form an insoluble complex. This plutonium cupferride precipitates and may then be separated from the solution.

  10. Plutonium concentrations in lichens of Rocky Flats environs

    SciTech Connect

    Thomas, R.S.; Ibrahim, S.A.

    1995-03-01

    Xanthoparmelia spp. lichens were used to study the spatial distribution of plutonium concentrations in nonvascular plants surrounding the Rocky Flats nuclear weapons facility with respect to distance, direction, age, and washing. Plutonium concentrations in lichens were inversely related to distance from the initial contamination site with a directional component which corroborated wind-borne transport as the primary means of dispersion. Ultrasonic washing and the relative age of the lichen proved to be significant only at p = 0.21 and p = 0.96, respectively. Isotopic ratios of {sup 239,240}Pu to {sup 238}Pu were highly variable at low activities but remained consistent at 62.6 for samples with high total plutonium activity. Correlation of Xanthoparmelia spp. lichen {sup 239,240}Pu concentrations to surface soil concentrations showed a direct relationship (r = 0.767; p < 0.001). The correlation was supported by soil retention studies which revealed a lichen soil content ranging from 11 to 18% on a dry mass basis with a possible particle size selectivity in the different concentration ratios adjacent to and away from the initial contamination site. Results suggest that further study into the in situ biomonitoring of surface soil by Xanthoparmelia spp. lichens is promising. 38 refs., 4 figs., 3 tabs.

  11. Plutonium concentrations in lichens of Rocky Flats environs.

    PubMed

    Thomas, R S; Ibrahim, S A

    1995-03-01

    Xanthoparmelia spp. lichens were used to study the spatial distribution of plutonium concentrations in nonvascular plants surrounding the Rocky Flats nuclear weapons facility with respect to distance, direction, age, and washing. Plutonium concentrations in lichens were inversely related to distance from the initial contamination site with a directional component which corroborated wind-borne transport as the primary means of dispersion. Ultrasonic washing and the relative age of the lichen proved to be significant only at p = 0.21 and p = 0.96, respectively. Isotopic ratios of 239,240Pu to 238Pu were highly variable at low activities but remained consistent at 62.6 for samples with high total plutonium activity. Correlation of Xanthoparmelia spp. lichen 239,240Pu concentrations to surface soil concentrations showed a direct relationship (r = 0.767; p < 0.001). The correlation was supported by soil retention studies which revealed a lichen soil content ranging from 11 to 18% on a dry mass basis with a possible particle size selectivity in the different concentration ratios adjacent to and away from the initial contamination site. Results suggest that further study into the in situ biomonitoring of surface soil by Xanthoparmelia spp. lichens is promising. PMID:7860301

  12. METHOD OF REDUCING PLUTONIUM WITH FERROUS IONS

    DOEpatents

    Dreher, J.L.; Koshland, D.E.; Thompson, S.G.; Willard, J.E.

    1959-10-01

    A process is presented for separating hexavalent plutonium from fission product values. To a nitric acid solution containing the values, ferrous ions are added and the solution is heated and held at elevated temperature to convert the plutonium to the tetravalent state via the trivalent state and the plutonium is then selectively precipitated on a BiPO/sub 4/ or LaF/sub 3/ carrier. The tetravalent plutonium formed is optionally complexed with fluoride, oxalate, or phosphate anion prior to carrier precipitation.

  13. Work and disproportionation for aqueous plutonium.

    PubMed

    Silver, G L

    2003-10-01

    The relation of two plutonium work integrals has recently been illustrated. One of the integrals applies to the work of disproportionation of tetravalent plutonium in 1 M acid and the other to the work of oxidation of plutonium from the trivalent to a higher oxidation state. This paper generalizes the disproportionation work integral so that it can be applied to tetravalent plutonium at any acid concentration. An equation is provided that can be used to verify work estimations obtained by integration. It applies to oxidation and disproportionation processes and it is easy to use. PMID:14522227

  14. OXIDATIVE METHOD OF SEPARATING PLUTONIUM FROM NEPTUNIUM

    DOEpatents

    Beaufait, L.J. Jr.

    1958-06-10

    A method is described of separating neptunium from plutonium in an aqueous solution containing neptunium and plutonium in valence states not greater than +4. This may be accomplished by contacting the solution with dichromate ions, thus oxidizing the neptunium to a valence state greater than +4 without oxidizing any substantial amount of plutonium, and then forming a carrier precipitate which carries the plutonium from solution, leaving the neptunium behind. A preferred embodiment of this invention covers the use of lanthanum fluoride as the carrier precipitate.

  15. NON-AQUEOUS DISSOLUTION OF MASSIVE PLUTONIUM

    DOEpatents

    Reavis, J.G.; Leary, J.A.; Walsh, K.A.

    1959-05-12

    A method is presented for obtaining non-aqueous solutions or plutonium from massive forms of the metal. In the present invention massive plutonium is added to a salt melt consisting of 10 to 40 weight per cent of sodium chloride and the balance zinc chloride. The plutonium reacts at about 800 deg C with the zinc chloride to form a salt bath of plutonium trichloride, sodium chloride, and metallic zinc. The zinc is separated from the salt melt by forcing the molten mixture through a Pyrex filter.

  16. Plutonium 238 facilities at Los Alamos

    NASA Astrophysics Data System (ADS)

    Rinehart, Gary H.

    1991-01-01

    Plutonium 238 operations at Los Alamos are performed at the Plutonium Facility (TA-55), the Chemistry and Metallurgy Research (CMR) Building, and the Radioisotope Fuels Impact Test Facility. The plutonium 238 facilities at Los Alamos support a wide variety of heat source activities including development of new fuel forms and containment materials, research on the high temperature properties of containment materials, investigation of the high temperature compatibility of fuels with potential container materials, processing plutonium 238 fuel forms, manufacture of heat sources under quality assurance surveillance, and performing safety testing on heat sources and radioisotope thermoelectric generators.

  17. Plutonium-238 facilities at Los Alamos

    NASA Astrophysics Data System (ADS)

    Rinehart, Gary H.

    Plutonium-238 operations at Los Alamos are performed at the Plutonium Facility (TA-55), the Chemistry and Metallurgy Research (CMR) Building, and the Radioisotope Fuels Impact Test Facility. The plutonium-238 facilities at Los Alamos support a wide variety of heat source activities including development of new fuel forms and containment materials, research on the high temperature properties of containment materials, investigation of the high temperature compatibility of fuels with potential container materials, processing plutonium-238 fuel forms, manufacture of heat sources under quality assurance surveillance, and performing safety testing on heat sources and radioisotope thermoelectric generators.

  18. ION EXCHANGE ADSORPTION PROCESS FOR PLUTONIUM SEPARATION

    DOEpatents

    Boyd, G.E.; Russell, E.R.; Taylor, M.D.

    1961-07-11

    Ion exchange processes for the separation of plutonium from fission products are described. In accordance with these processes an aqueous solution containing plutonium and fission products is contacted with a cation exchange resin under conditions favoring adsorption of plutonium and fission products on the resin. A portion of the fission product is then eluted with a solution containing 0.05 to 1% by weight of a carboxylic acid. Plutonium is next eluted with a solution containing 2 to 8 per cent by weight of the same carboxylic acid, and the remaining fission products on the resin are eluted with an aqueous solution containing over 10 per cent by weight of sodium bisulfate.

  19. Plutonium oxalate precipitation for trace elemental determination in plutonium materials

    DOE PAGESBeta

    Xu, Ning; Gallimore, David; Lujan, Elmer; Garduno, Katherine; Walker, Laurie; Taylor, Fiona; Thompson, Pam; Tandon, Lav

    2015-05-26

    In this study, an analytical chemistry method has been developed that removes the plutonium (Pu) matrix from the dissolved Pu metal or oxide solution prior to the determination of trace impurities that are present in the metal or oxide. In this study, a Pu oxalate approach was employed to separate Pu from trace impurities. After Pu(III) was precipitated with oxalic acid and separated by centrifugation, trace elemental constituents in the supernatant were analyzed by inductively coupled plasma-optical emission spectroscopy with minimized spectral interferences from the sample matrix.

  20. Critical experiments on single-unit spherical plutonium geometries reflected and moderated by oil

    SciTech Connect

    Rothe, R.E.

    1997-05-01

    Experimental critical configurations are reported for several dozen spherical and hemispherical single-unit assemblies of plutonium metal. Most were solid but many were hollow-centered, thick, shell-like geometries. All were constructed of nested plutonium (mostly {sup 2139}Pu) metal hemispherical shells. Three kinds of critical configurations are reported. Two required interpolation and/or extrapolation of data to obtain the critical mass because reflector conditions were essentially infinite. The first finds the plutonium essentially fully reflected by a hydrogen-rich oil; the second is essentially unreflected. The third kind reports the critical oil reflector height above a large plutonium metal assembly of accurately known mass (no interpolation required) when that mass was too great to permit full oil reflection. Some configurations had thicknesses of mild steel just outside the plutonium metal, separating it from the oil. These experiments were performed at the Rocky Flats Critical Mass Laboratory in the late 1960s. They have not been published in a form suitable for benchmark-quality comparisons against state-of-the-art computational techniques until this paper. The age of the data and other factors lead to some difficulty in reconstructing aspects of the program and may, in turn, decrease confidence in certain details. Whenever this is true, the point is acknowledged. The plutonium metal was alpha-phase {sup 239}Pu containing 5.9 wt-% {sup 240}Pu. All assemblies were formed by nesting 1.667-mm-thick (nominal) bare plutonium metal hemispherical shells, also called hemishells, until the desired configuration was achieved. Very small tolerance gaps machined into radial dimensions reduced the effective density a small amount in all cases. Steel components were also nested hemispherical shells; but these were nominally 3.333-mm thick. Oil was used as the reflector because of its chemical compatibility with plutonium metal.

  1. Alloy materials

    DOEpatents

    Hans Thieme, Cornelis Leo; Thompson, Elliott D.; Fritzemeier, Leslie G.; Cameron, Robert D.; Siegal, Edward J.

    2002-01-01

    An alloy that contains at least two metals and can be used as a substrate for a superconductor is disclosed. The alloy can contain an oxide former. The alloy can have a biaxial or cube texture. The substrate can be used in a multilayer superconductor, which can further include one or more buffer layers disposed between the substrate and the superconductor material. The alloys can be made a by process that involves first rolling the alloy then annealing the alloy. A relatively large volume percentage of the alloy can be formed of grains having a biaxial or cube texture.

  2. Pyrochemical process for extracting plutonium from an electrolyte salt

    DOEpatents

    Mullins, Lawrence J.; Christensen, Dana C.

    1984-01-01

    A pyrochemical process for extracting plutonium from a plutonium-bearing salt is disclosed. The process is particularly useful in the recovery of plutonium from electrolyte salts which are left over from the electrorefining of plutonium. In accordance with the process, the plutonium-bearing salt is melted and mixed with metallic calcium. The calcium reduces ionized plutonium in the salt to plutonium metal, and also causes metallic plutonium in the salt, which is typically present as finely dispersed metallic shot, to coalesce. The reduced and coalesced plutonium separates out on the bottom of the reaction vessel as a separate metallic phase which is readily separable from the overlying salt upon cooling of the mixture. Yields of plutonium are typically on the order of 95%. The stripped salt is virtually free of plutonium and may be discarded to low-level waste storage.

  3. Pyrochemical process for extracting plutonium from an electrolyte salt

    DOEpatents

    Mullins, L.J.; Christensen, D.C.

    1982-09-20

    A pyrochemical process for extracting plutonium from a plutonium-bearing salt is disclosed. The process is particularly useful in the recovery of plutonium for electrolyte salts which are left over from the electrorefining of plutonium. In accordance with the process, the plutonium-bearing salt is melted and mixed with metallic calcium. The calcium reduces ionized plutonium in the salt to plutonium metal, and also causes metallic plutonium in the salt, which is typically present as finely dispersed metallic shot, to coalesce. The reduced and coalesced plutonium separates out on the bottom of the reaction vessel as a separate metallic phase which is readily separable from the overlying salt upon cooling of the mixture. Yields of plutonium are typically on the order of 95%. The stripped salt is virtually free of plutonium and may be discarded to low-level waste storage.

  4. URANOUS IODATE AS A CARRIER FOR PLUTONIUM

    DOEpatents

    Miller, D.R.; Seaborg, G.T.; Thompson, S.G.

    1959-12-15

    A process is described for precipitating plutonium on a uranous iodate carrier from an aqueous acid solution conA plutonium solution more concentrated than the original solution can then be obtained by oxidizing the uranium to the hexavalent state and dissolving the precipitate, after separating the latter from the original solution, by means of warm nitric acid.

  5. Plutonium disproportionation: the relation of work integrals.

    PubMed

    Silver, G L

    2003-04-01

    Two plutonium work integrals have been demonstrated in recent years. One of them applies to the work of disproportionation and the other to the work of oxidation of plutonium from the trivalent to a higher oxidation state. This paper illustrates the connection of the integrals by an example and a diagram. PMID:12672623

  6. MOLTEN PLUTONIUM FUELED FAST BREEDER REACTOR

    DOEpatents

    Kiehn, R.M.; King, L.D.P.; Peterson, R.E.; Swickard, E.O. Jr.

    1962-06-26

    A description is given of a nuclear fast reactor fueled with molten plutonium containing about 20 kg of plutonium in a tantalum container, cooled by circulating liquid sodium at about 600 to 650 deg C, having a large negative temperature coefficient of reactivity, and control rods and movable reflector for criticality control. (AEC)

  7. Plutonium Immobilization Project -- Robotic canister loading

    SciTech Connect

    Hamilton, L.

    2000-04-28

    The Plutonium Immobilization Program (PIP) is a joint venture between the Savannah River Site, Lawrence Livermore National Laboratory, Argonne National Laboratory, and Pacific Northwest National Laboratory. When operational in 2008, the PIP will fulfill the nation's nonproliferation commitment by placing surplus weapons-grade plutonium in a permanently stable ceramic form.

  8. RECOVERY OF PLUTONIUM BY CARRIER PRECIPITATION

    DOEpatents

    Goeckermann, R.H.

    1961-04-01

    A process is given for recovering plutonium from an aqueous nitric acid zirconium-containing solution of an acidity between 0.2 and 1 N by adding fluoride anions (1.5 to 5 mg/l) and precipitating the plutonium with an excess of hydrogen peroxide at from 53 to 65 deg C.

  9. Nondestructive assay methods for solids containing plutonium

    SciTech Connect

    Macmurdo, K.W.; Gray, L.W.; Gibbs, A.

    1984-06-01

    Specific nondestructive assay (NDA) methods, e.g. calorimetry, coincidence neutron counting, singles neutron counting, and gamma ray spectrometry, were studied to provide the Savannah River Plant with an NDA method to measure the plutonium content of solid scrap (slag and crucible) generated in the JB-Line plutonium metal production process. Results indicate that calorimetry can be used to measure the plutonium content to within about 3% in 4 to 6 hours by using computerized equilibrium sample power predictive models. Calorimetry results confirm that a bias exists in the present indirect measurement method used to estimate the plutonium content of slag and crucible. Singles neutron counting of slag and crucible can measure plutonium to only +-30%, but coincidence neutron counting methods improve measurement precision to better than +-10% in less than ten minutes. Only four portions of a single slag and crucible sample were assayed, and further study is recommended.

  10. New Fecal Method for Plutonium and Americium

    SciTech Connect

    Maxwell, S.L. III

    2000-06-27

    A new fecal analysis method that dissolves plutonium oxide was developed at the Westinghouse Savannah River Site. Diphonix Resin (Eichrom Industries), is used to pre-concentrate the actinides from digested fecal samples. A rapid microwave digestion technique is used to remove the actinides from the Diphonix Resin, which effectively extracts plutonium and americium from acidic solutions containing hydrofluoric acid. After resin digestion, the plutonium and americium are recovered in a small volume of nitric acid that is loaded onto small extraction chromatography columns, TEVA Resin and TRU Resin (Eichrom Industries). The method enables complete dissolution of plutonium oxide and provides high recovery of plutonium and americium with good removal of thorium isotopes such as thorium-228.

  11. PROCESS FOR THE RECOVERY OF PLUTONIUM

    DOEpatents

    Ritter, D.M.

    1959-01-13

    An improvement is presented in the process for recovery and decontamination of plutonium. The carrier precipitate containing plutonium is dissolved and treated with an oxidizing agent to place the plutonium in a hexavalent oxidation state. A lanthanum fluoride precipitate is then formed in and removed from the solution to carry undesired fission products. The fluoride ions in the reniaining solution are complexed by addition of a borate sueh as boric acid, sodium metaborate or the like. The plutonium is then reduced and carried from the solution by the formation of a bismuth phosphate precipitate. This process effects a better separation from unwanted flssion products along with conccntration of the plutonium by using a smaller amount of carrier.

  12. Reversible expansion of gallium-stabilized delta-plutonium

    SciTech Connect

    Wolfer, W; Oudot, B; Baclet, N

    2006-01-26

    The transient expansion of plutonium-gallium alloys observed both in the lattice parameter as well as in the dimension of a sample held at ambient temperature is explained by assuming incipient precipitation of Pu{sub 3}Ga. However, this ordered {zeta}{prime}-phase is also subject to radiation-induced disordering. As a result, the gallium-stabilized {delta}-phase, being metastable at ambient temperature, is both driven towards thermodynamic equilibrium by radiation-enhanced diffusion of gallium and at the same time pushed back to its metastable state by radiation-induced disordering. A steady state is reached in which only a modest fraction of the gallium present is tied up in the {zeta}{prime}-phase.

  13. Reversible expansion of gallium-stabilized (delta)-plutonium

    SciTech Connect

    Wolfer, W G; Oudot, B; Baclet, N

    2006-02-27

    It is shown that the transient expansion of plutonium-gallium alloys observed both in the lattice parameter as well as in the dimension of a sample held at ambient temperature can be explained by assuming incipient precipitation of Pu{sub 3}Ga. However, this ordered {zeta}-phase is also subject to radiation-induced disordering. As a result, the gallium-stabilized {delta}-phase, being metastable at ambient temperature, is driven towards thermodynamic equilibrium by radiation-enhanced diffusion of gallium and at the same time reverted back to its metastable state by radiation-induced disordering. A steady state is reached in which only a modest fraction of the gallium present is arranged in ordered {zeta}-phase regions.

  14. Probing Radiation Damage in Plutonium Alloys with Multiple Measurement Techniques

    SciTech Connect

    McCall, S K; Fluss, M J; Chung, B W

    2010-04-21

    A material subjected to radiation damage will usually experience changes in its physical properties. Measuring these changes in the physical properties provides a basis to study radiation damage in a material which is important for a variety of real world applications from reactor materials to semiconducting devices. When investigating radiation damage, the relative sensitivity of any given property can vary considerably based on the concentration and type of damage present as well as external parameters such as the temperature and starting material composition. By measuring multiple physical properties, these differing sensitivities can be leveraged to provide greater insight into the different aspects of radiation damage accumulation, thereby providing a broader understanding of the mechanisms involved. In this report, self-damage from {alpha}-particle decay in Pu is investigated by measuring two different properties: magnetic susceptibility and resistivity. The results suggest that while the first annealing stage obeys second order chemical kinetics, the primary mechanism is not the recombination of vacancy-interstitial close pairs.

  15. REMOVAL OF LEGACY PLUTONIUM MATERIALS FROM SWEDEN

    SciTech Connect

    Dunn, Kerry A.; Bellamy, J. Steve; Chandler, Greg T.; Iyer, Natraj C.; Koenig, Rich E.; Leduc, D.; Hackney, B.; Leduc, Dan R.; McClard, J. W.

    2013-08-18

    U.S. Department of Energy’s National Nuclear Security Administration (NNSA) Office of Global Threat Reduction (GTRI) recently removed legacy plutonium materials from Sweden in collaboration with AB SVAFO, Sweden. This paper details the activities undertaken through the U.S. receiving site (Savannah River Site (SRS)) to support the characterization, stabilization, packaging and removal of legacy plutonium materials from Sweden in 2012. This effort was undertaken as part of GTRI’s Gap Materials Program and culminated with the successful removal of plutonium from Sweden as announced at the 2012 Nuclear Security Summit. The removal and shipment of plutonium materials to the United States was the first of its kind under NNSA’s Global Threat Reduction Initiative. The Environmental Assessment for the U.S. receipt of gap plutonium material was approved in May 2010. Since then, the multi-year process yielded many first time accomplishments associated with plutonium packaging and transport activities including the application of the of DOE-STD-3013 stabilization requirements to treat plutonium materials outside the U.S., the development of an acceptance criteria for receipt of plutonium from a foreign country, the development and application of a versatile process flow sheet for the packaging of legacy plutonium materials, the identification of a plutonium container configuration, the first international certificate validation of the 9975 shipping package and the first intercontinental shipment using the 9975 shipping package. This paper will detail the technical considerations in developing the packaging process flow sheet, defining the key elements of the flow sheet and its implementation, determining the criteria used in the selection of the transport package, developing the technical basis for the package certificate amendment and the reviews with multiple licensing authorities and most importantly integrating the technical activities with the Swedish partners.

  16. Field test of New TASTEX system for plutonium product verification at the Tokai Reprocessing Plant

    SciTech Connect

    Kuno, Y.; Shigeoka, K.; Nishida, K.; Ikeda, H.; Hayashi, N.; Wachi, I.; Hsue, S.T.; Sprinkle, J.K.; Gunnink, R.; Ruhter, W.D.

    1988-01-01

    This report describes the field test results of the New TASTEX system. This system consisting of the high resolution gamma spectrometer and the k-edge densitometer can measure both isotopic abundances and concentration of plutonium simultaneously. Entire system is controlled by the multichannel analyzer and a multi-user computer. The system was designed and built under the Japan Support Program for Agency Safeguards (JASPAS). The software of this system developed at LANL and LLNL has been installed in the system assembled at the Tokai reprocessing plant (TRP) in July 1985. In the course of campaigns from 1985 until 1988, field tests have been carried out on plutonium product solutions of TRP. The results of plutonium concentration and isotopic abundances obtained by the k-edge densitometer and the high resolution gamma spectrometer (HRGS) have been compared with those by controlled potential coulometer and mass spectrometer respectively. Precision of plutonium determination with k-edge densitometer is estimated approximately 0.7% and 1.0% for the freshly processed plutonium and the aged plutonium respectively. The scatters in the relative differences between HRGS and the destructive analysis (DA) detected on the results of freshly processed plutonium sample were 1.6%, 0.4%, 0.5%, 1.1%, 8.0% for Pu-238, Pu-239, Pu-240, Pu-241, and Pu-242 respectively, whereas those on the results of aged sample were 1.4%, 0.5%, 1.1%, 1.1% for Pu-238, Pu-239, Pu-240, and Pu-241 respectively. 9 refs., 15 figs., 7 tabs.

  17. An update of epidemiologic studies of plutonium workers.

    PubMed

    Voelz, G L; Wilkinson, G S; Acquavella, J F; Tietjen, G L; Brackbill, R N; Reyes, M; Wiggs, L D

    1983-01-01

    Retrospective and prospective epidemiologic studies are being conducted as part of a national survey of plutonium workers at four Department of Energy facilities (Los Alamos, NM; Rocky Flats, CO; Mound Laboratory, OH; and Savannah River, SC). A preliminary analysis of mortality was done for all white males who have worked at the Rocky Flats Plant during the period 1952-79. The 452 observed deaths were significantly fewer than the 831 expected for all causes. The 107 deaths due to all malignant neoplasms were also significantly fewer than the 167 expected from these diseases. Expected deaths were derived from age and calendar-specific death rates for U.S. white males. Deaths reported for benign and unspecified neoplasms numbered eight versus an expected two, a significant elevation. These tumors, all intracranial, are the subject of a case-control study to be reported later. Subdividing the cohort on the basis of plutonium exposures and external radiation exposures results in similar overall findings. The benign and unspecified neoplasms, however, were not significantly high in the plutonium-exposed group. PMID:6862925

  18. Plutonium focus area. Technology summary

    SciTech Connect

    1997-09-01

    The Assistant Secretary for the Office of Environmental Management (EM) at the U.S. Department of Energy (DOE) chartered the Plutonium Focus Area (PFA) in October 1995. The PFA {open_quotes}...provides for peer and technical reviews of research and development in plutonium stabilization activities...{close_quotes} In addition, the PFA identifies and develops relevant research and technology. The purpose of this document is to focus attention on the requirements used to develop research and technology for stabilization, storage, and preparation for disposition of nuclear materials. The PFA Technology Summary presents the approach the PFA uses to identify, recommend, and review research. It lists research requirements, research being conducted, and gaps where research is needed. It also summarizes research performed by the PFA in the traditional research summary format. This document encourages researchers and commercial enterprises to do business with PFA by submitting research proposals or {open_quotes}white papers.{close_quotes} In addition, it suggests ways to increase the likelihood that PFA will recommend proposed research to the Nuclear Materials Stabilization Task Group (NMSTG) of DOE.

  19. Ceramification: A plutonium immobilization process

    SciTech Connect

    Rask, W.C.; Phillips, A.G.

    1996-05-01

    This paper describes a low temperature technique for stabilizing and immobilizing actinide compounds using a combination process/storage vessel of stainless steel, in which measured amounts of actinide nitrate solutions and actinide oxides (and/or residues) are systematically treated to yield a solid article. The chemical ceramic process is based on a coating technology that produces rare earth oxide coatings for defense applications involving plutonium. The final product of this application is a solid, coherent actinide oxide with process-generated encapsulation that has long-term environmental stability. Actinide compounds can be stabilized as pure materials for ease of re-use or as intimate mixtures with additives such as rare earth oxides to increase their degree of proliferation resistance. Starting materials for the process can include nitrate solutions, powders, aggregates, sludges, incinerator ashes, and others. Agents such as cerium oxide or zirconium oxide may be added as powders or precursors to enhance the properties of the resulting solid product. Additives may be included to produce a final product suitable for use in nuclear fuel pellet production. The process is simple and reduces the time and expense for stabilizing plutonium compounds. It requires a very low equipment expenditure and can be readily implemented into existing gloveboxes. The process is easily conducted with less associated risk than proposed alternative technologies.

  20. ADSORPTION-BISMUTH PHOSPHATE METHOD FOR SEPARATING PLUTONIUM

    DOEpatents

    Russell, E.R.; Adamson, A.W.; Boyd, G.E.

    1960-06-28

    A process is given for separating plutonium from uranium and fission products. Plutonium and uranium are adsorbed by a cation exchange resin, plutonium is eluted from the adsorbent, and then, after oxidation to the hexavalent state, the plutonium is contacted with a bismuth phosphate carrier precipitate.

  1. Chemical and Radiochemical Composition of Thermally Stabilized Plutonium Oxide from the Plutonium Finishing Plant Considered as Alternate Feedstock for the Mixed Oxide Fuel Fabrication Facility

    SciTech Connect

    Tingey, Joel M.; Jones, Susan A.

    2005-07-01

    PFP. Samples varied in appearance depending on the original source of material. Rocky Flats items were mostly dark olive green with clumps that crushed easily with a mortar and pestle. PRF/RMC items showed more variability. These items were mostly rust colored. One sample contained white particles that were difficult to crush, and another sample was a dark grey with a mixture of fines and large, hard fragments. The appearance and feel of the fragments indicated they might be an alloy. The color of the solution samples was indicative of the impurities in the sample. The double-pass filtrate solution was a brown color indicative of the iron impurities in the sample. The other solution sample was light gray in color. Radiochemical analyses, including thermal ionization mass spectrometry (TIMS), alpha and gamma energy analysis (AEA and GEA), and kinetic phosphorescence analysis (KPA), indicate that these materials are all weapons-grade plutonium with consistent plutonium isotopics. A small amount of uranium (<0.14 wt%) is also present in these samples. The isotopic composition of the uranium varied widely but was consistent among each category of material. The primary water-soluble anions in these samples were Cl-, NO3-, SO42-, and PO43-. The only major anion observed in the Rocky Flats materials was Cl-, but the PRF/RMC samples had significant quantities of all of the primary anions observed. Prompt gamma measurements provide a representative analysis of the Cl- concentration in the bulk material. The primary anions observed in the solution samples were NO3-, and PO43-. The concentration of these anions did not exceed the mixed oxide (MOX) specification limits. Cations that exceeded the MOX specification limits included Cr, Fe, Ni, Al, Cu, and Si. All of the samples exceeded at least the 75% specification limit in one element.

  2. Excess Plutonium: Weapons Legacy or National Asset?

    SciTech Connect

    Klipa, G.; Boeke, S.; Hottel, R.

    2002-02-27

    The Nuclear Materials Stewardship Initiative was established in January, 2000, to accelerate the work of achieving integration and cutting long-term costs associated with the management of nuclear materials. As part of that initiative, the Department of Energy (DOE), Office of Environmental Management (EM), has established Nuclear Material Management Groups for the management of excess nuclear materials. As one of these groups, the Plutonium Material Management Group (PMMG) has been chartered to serve as DOE's complex wide resource and point of contact for technical coordination and program planning support in the safe and efficient disposition of the nations excess Plutonium 239. This paper will explain the mission, goals, and objectives of the PMMG. In addition, the paper will provide a broad overview of the status of the plutonium inventories throughout the DOE complex. The DOE currently manages approximately 99.5 MT of plutonium isotopes. Details of the various categories of plutonium, from material designated for national security needs through material that has been declared excess, will be explained. For the plutonium that has been declared excess, the various pathways to disposition (including reuse, recycling, sale, transfer, treatment, consumption, and disposal) will be discussed. At this time 52.5 MT of plutonium has been declared excess and the method of disposition for that material is the subject of study and evaluation within DOE. The role of the PMMG in those evaluations will be outlined.

  3. How much plutonium does North Korea have?

    SciTech Connect

    Albright, D.

    1994-09-01

    U.S. intelligence discovered in the 1980s that North Korea was building a small nuclear reactor. The reactor was described as a gas-cooled, graphite-moderated model similar to those Britian and France used to produce electric power as well as plutonium for nuclear weapons. When Western nations expressed concern about the reactor Russia pressed North Korea to sign the Non-Proliferation Treaty (NPT) which it did on December 12, 1985. However, North Korea stalled on signing the required safeguards agreement that allows the International Atomic Energy Agency (IAEA) to inspect nuclear facilities until January 1992. Inspections by the IAEA revealed discrepancies with the amounts of plutonium separated as declared by the North Koreans. The IAEA also received reports that two North Korean waste sites were hidden. By February 1993 the IAEA and the North Koreans has reached an impasse: North Koreas initial declarations of plutonium inventory could not be confirmed and North Korea refused to cooperate. At the least, North Korea admits to having separated 100 grams of plutonium. At the most, worst case estimate, they could have a total of 6 - 13 kilograms of separated plutonium. A first nuclear weapon can require up to 10 kilograms of weapon-grade plutonium. Any settlement needs to include a way to insure that the IAEA can verify North Korea`s past nuclear activities and determine the amount of plutonium that may have been separated in the past. 2 refs.

  4. 10 CFR 140.108 - Appendix H-Form of indemnity agreement with licensees possessing plutonium for use in plutonium...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... possessing plutonium for use in plutonium processing and fuel fabrication plants and furnishing proof of... Appendixes to Part 140 § 140.108 Appendix H—Form of indemnity agreement with licensees possessing plutonium for use in plutonium processing and fuel fabrication plants and furnishing proof of...

  5. 10 CFR 140.108 - Appendix H-Form of indemnity agreement with licensees possessing plutonium for use in plutonium...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... possessing plutonium for use in plutonium processing and fuel fabrication plants and furnishing proof of... Appendixes to Part 140 § 140.108 Appendix H—Form of indemnity agreement with licensees possessing plutonium for use in plutonium processing and fuel fabrication plants and furnishing proof of...

  6. Volatile fluoride process for separating plutonium from other materials

    DOEpatents

    Spedding, F. H.; Newton, A. S.

    1959-04-14

    The separation of plutonium from uranium and/or fission products by formation of the higher fluorides off uranium and/or plutonium is described. Neutronirradiated uranium metal is first converted to the hydride. This hydrided product is then treated with fluorine at about 315 deg C to form and volatilize UF/sub 6/ leaving plutonium behind. Thc plutonium may then be separated by reacting the residue with fluorine at about 5004DEC and collecting the volatile plutonium fluoride thus formed.

  7. VOLATILE FLUORIDE PROCESS FOR SEPARATING PLUTONIUM FROM OTHER MATERIALS

    DOEpatents

    Spedding, F.H.; Newton, A.S.

    1959-04-14

    The separation of plutonium from uranium and/or tission products by formation of the higher fluorides of uranium and/or plutonium is discussed. Neutronirradiated uranium metal is first convcrted to the hydride. This hydrided product is then treatced with fluorine at about 315 deg C to form and volatilize UF/sup 6/ leaving plutonium behind. The plutonium may then be separated by reacting the residue with fluorine at about 500 deg C and collecting the volatile plutonium fluoride thus formed.

  8. NON-CORROSIVE PLUTONIUM FUEL SYSTEMS

    DOEpatents

    Coffinberry, A.S.; Waber, J.T.

    1962-10-23

    An improved plutonium reactor liquid fuel is described for utilization in a nuclear reactor having a tantalum fuel containment vessel. The fuel consists of plutonium and a diluent such as iron, cobalt, nickel, cerium, cerium-- iron, cerium--cobalt, cerium--nickel, and cerium--copper, and an additive of carbon and silicon. The carbon and silicon react with the tantalum container surface to form a coating that is self-healing and prevents the corrosive action of liquid plutonium on the said tantalum container. (AEC)

  9. Plutonium Immobilization Can Loading Conceptual Design

    SciTech Connect

    Kriikku, E.

    1999-05-13

    'The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. This report discusses the Plutonium Immobilization can loading conceptual design and includes a process block diagram, process description, preliminary equipment specifications, and several can loading issues. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas.'

  10. Removal of plutonium from hepatic tissue

    DOEpatents

    Lindenbaum, Arthur; Rosenthal, Marcia W.

    1979-01-01

    A method is provided for removing plutonium from hepatic tissues by introducing into the body and blood stream a solution of the complexing agent DTPA and an adjunct thereto. The adjunct material induces aberrations in the hepatic tissue cells and removes intracellularly deposited plutonium which is normally unavailable for complexation with the DTPA. Once the intracellularly deposited plutonium has been removed from the cell by action of the adjunct material, it can be complexed with the DTPA present in the blood stream and subsequently removed from the body by normal excretory processes.

  11. SEPARATION OF URANIUM, PLUTONIUM AND FISSION PRODUCTS

    DOEpatents

    Nicholls, C.M.; Wells, I.; Spence, R.

    1959-10-13

    The separation of uranium and plutonium from neutronirradiated uranium is described. The neutron-irradiated uranium is dissolved in nitric acid to provide an aqueous solution 3N in nitric acid. The fission products of the solution are extruded by treating the solution with dibutyl carbitol substantially 1.8N in nitric acid. The organic solvent phase is separated and neutralized with ammonium hydroxide and the plutonium reduced with hydroxylamine base to the trivalent state. Treatment of the mixture with saturated ammonium nitrate extracts the reduced plutonium and leaves the uranium in the organic solvent.

  12. RECOVERY OF PLUTONIUM FROM AQUEOUS SOLUTIONS

    DOEpatents

    Reber, E.J.

    1959-09-01

    A process is described for recovering plutonium values from aqueous solutions by precipitation on bismuth phosphate. The plutonium is secured in its tetravalent state. bismuth salt is added to the solution, and ant excess of phosphoric acid anions is added to the solution in two approximately equal installments. The rate of addition of the first installment is about two to three times as high as the rate of addition of the second installment, whereby a precipitate of bismuth phosphate forms, the precipitate carrying the plutonium values. The precipitate is separated from the solution.

  13. Excess Weapons Plutonium Immobilization in Russia

    SciTech Connect

    Jardine, L.; Borisov, G.B.

    2000-04-15

    The joint goal of the Russian work is to establish a full-scale plutonium immobilization facility at a Russian industrial site by 2005. To achieve this requires that the necessary engineering and technical basis be developed in these Russian projects and the needed Russian approvals be obtained to conduct industrial-scale immobilization of plutonium-containing materials at a Russian industrial site by the 2005 date. This meeting and future work will provide the basis for joint decisions. Supporting R&D projects are being carried out at Russian Institutes that directly support the technical needs of Russian industrial sites to immobilize plutonium-containing materials. Special R&D on plutonium materials is also being carried out to support excess weapons disposition in Russia and the US, including nonproliferation studies of plutonium recovery from immobilization forms and accelerated radiation damage studies of the US-specified plutonium ceramic for immobilizing plutonium. This intriguing and extraordinary cooperation on certain aspects of the weapons plutonium problem is now progressing well and much work with plutonium has been completed in the past two years. Because much excellent and unique scientific and engineering technical work has now been completed in Russia in many aspects of plutonium immobilization, this meeting in St. Petersburg was both timely and necessary to summarize, review, and discuss these efforts among those who performed the actual work. The results of this meeting will help the US and Russia jointly define the future direction of the Russian plutonium immobilization program, and make it an even stronger and more integrated Russian program. The two objectives for the meeting were to: (1) Bring together the Russian organizations, experts, and managers performing the work into one place for four days to review and discuss their work with each other; and (2) Publish a meeting summary and a proceedings to compile reports of all the excellent

  14. HENC performance evaluation and plutonium calibration

    SciTech Connect

    Menlove, H.O.; Baca, J.; Pecos, J.M.; Davidson, D.R.; McElroy, R.D.; Brochu, D.B.

    1997-10-01

    The authors have designed a high-efficiency neutron counter (HENC) to increase the plutonium content in 200-L waste drums. The counter uses totals neutron counting, coincidence counting, and multiplicity counting to determine the plutonium mass. The HENC was developed as part of a Cooperative Research and Development Agreement between the Department of Energy and Canberra Industries. This report presents the results of the detector modifications, the performance tests, the add-a-source calibration, and the plutonium calibration at Los Alamos National Laboratory (TA-35) in 1996.

  15. Incidence of plutonium-induced bone cancer in neutered mice

    SciTech Connect

    Taylor, G.N.; Gardner, P.; Mays, C.W.; Wrenn, M.E.; Charrier, K.

    1981-03-01

    The incidence of bone cancer, after a single i.p. injection of monomeric /sup 239/Pu citrate, is significantly higher in female than in male mice. To evaluate the role of the gonads in this sex-related difference, male and female C57BL/Do (albino) mice were castrated at 40 days of age. Fifty days later, they were given injections of /sup 239/Pu. After castration, the frequency of bone sarcomas in the two sexes was approximately equal. This resulted from an increased incidence in the castrated males and a decreased incidence in the ovariectomized females as compared to the intact plutonium-treated mice.

  16. Upgrade of the Los Alamos Plutonium Facility control system

    SciTech Connect

    Pope, N.G.; Turner, W.J.; Brown, R.E.; Bibeau, R.A.; Davis, R.R.; Hogan, K.

    1996-05-01

    After 20 yrs service, the Los Alamos Plutonium Facility is undergoing an upgrade to its aging Facility Control System. The new system design includes a network of redundantly-paired programmable logic controllers that will interface with about 2200 field data points. The data communications network that has been designed includes a redundant, self-healing fiber optic data highway as well as a fiber optic ethernet. Commercially available human-machine interface software running on a UNIX-based system displays facility subsystem status operator X-terminals. Project design features, methods, costs, and schedule are discussed.

  17. Weapons-grade plutonium dispositioning. Volume 4. Plutonium dispositioning in light water reactors

    SciTech Connect

    Sterbentz, J.W.; Olsen, C.S.; Sinha, U.P.

    1993-06-01

    This study is in response to a request by the Reactor Panel Subcommittee of the National Academy of Sciences (NAS) Committee on International Security and Arms Control (CISAC) to evaluate the feasibility of using plutonium fuels (without uranium) for disposal in existing conventional or advanced light water reactor (LWR) designs and in low temperature/pressure LWR designs that might be developed for plutonium disposal. Three plutonium-based fuel forms (oxides, aluminum metallics, and carbides) are evaluated for neutronic performance, fabrication technology, and material and compatibility issues. For the carbides, only the fabrication technologies are addressed. Viable plutonium oxide fuels for conventional or advanced LWRs include plutonium-zirconium-calcium oxide (PuO{sub 2}-ZrO{sub 2}-CaO) with the addition of thorium oxide (ThO{sub 2}) or a burnable poison such as erbium oxide (Er{sub 2}O{sub 3}) or europium oxide (Eu{sub 2}O{sub 3}) to achieve acceptable neutronic performance. Thorium will breed fissile uranium that may be unacceptable from a proliferation standpoint. Fabrication of uranium and mixed uranium-plutonium oxide fuels is well established; however, fabrication of plutonium-based oxide fuels will require further development. Viable aluminum-plutonium metallic fuels for a low temperature/pressure LWR include plutonium aluminide in an aluminum matrix (PuAl{sub 4}-Al) with the addition of a burnable poison such as erbium (Er) or europium (Eu). Fabrication of low-enriched plutonium in aluminum-plutonium metallic fuel rods was initially established 30 years ago and will require development to recapture and adapt the technology to meet current environmental and safety regulations. Fabrication of high-enriched uranium plate fuel by the picture-frame process is a well established process, but the use of plutonium would require the process to be upgraded in the United States to conform with current regulations and minimize the waste streams.

  18. PRODUCTION OF PLUTONIUM FLUORIDE FROM BISMUTH PHOSPHATE PRECIPITATE CONTAINING PLUTONIUM VALUES

    DOEpatents

    Brown, H.S.; Bohlmann, E.G.

    1961-05-01

    A process is given for separating plutonium from fission products present on a bismuth phosphate carrier. The dried carrier is first treated with hydrogen fluoride at between 500 and 600 deg C whereby some fission product fluorides volatilize away from plutonium tetrafluoride, and nonvolatile fission product fluorides are formed then with anhydrous fluorine at between 400 and 500 deg C. Bismuth and plutonium distill in the form of volatile fluorides away from the nonvolatile fission product fluorides. The bismuth and plutonium fluorides are condensed at below 290 deg C.

  19. What is plutonium stabilization, and what is safe storage of plutonium?

    SciTech Connect

    Forsberg, C.W.

    1995-06-29

    The end of the cold war has resulted in the shutdown of nuclear weapons production and the start of dismantlement of significant numbers of nuclear weapons. This, in turn, is creating an inventory of plutonium requiring interim and long-term storage. A key question is, ``What is required for safe, multidecade, plutonium storage?`` The requirements for storage, in turn, define what is needed to stabilize the plutonium from its current condition into a form acceptable for interim and long-term storage. Storage requirements determine if research is required to (1) define required technical conditions for interim and long-term storage and (2) develop or improve current stabilization technologies. Storage requirements depend upon technical, policy, and economic factors. The technical issues are complicated by several factors. Plutonium in aerosol form is highly hazardous. Plutonium in water is hazardous. The plutonium inventory is in multiple chemical forms--some of which are chemically reactive. Also, some of the existing storage forms are clearly unsuitable for storage periods over a few years. Gas generation by plutonium compounds complicates storage: (1) all plutonium slowly decays creating gaseous helium and (2) the radiation from plutonium decay can initiate many chemical reactions-some of which generate significant quantities of gases. Gas generation can pressurize sealed storage packages. Last nuclear criticality must be avoided.

  20. Single Point Incremental Forming of an Aged AL-Cu-Mg Alloy: Influence of Pre-heat Treatment and Warm Forming

    NASA Astrophysics Data System (ADS)

    Mohammadi, Amirahmad; Qin, Ling; Vanhove, Hans; Seefeldt, Marc; Van Bael, Albert; Duflou, Joost R.

    2016-06-01

    This research is aimed at enhancing the poor room temperature formability of heat-treatable aluminum alloy AA2024-T3, without deterioration of its post-forming properties. For this purpose, the influences of different heat-treatment conditions as well as warm forming on the single point incremental forming formability and post-forming properties of this material were investigated. Thermal pre-treatments were consisting of annealing (O-temper), solution treating and quenching (W-temper), and solution heat treating, quenching, and then cold working (T-temper). The formability results as well as forming forces of pre-heat-treated sheets were compared to those of the warm forming process results carried out using a laser-assisted single point incremental forming (LASPIF) setup. The post-forming properties of SPIF-formed parts were analyzed by hardness testing. The maximum forming angles of the blank formed under O-temper and W-temper conditions showed, respectively, 41 and 32% increases compared to the one under T-temper condition. LASPIF forming of this material at a temperature of about 360 °C resulted in 41% improvement in the maximum forming angle with respect to parts formed at room temperature from the T-temper sheet. The hardness of the material reduced significantly after annealing, while SPIF parts formed from W-temper blanks and under LASPIF condition regained their hardness after natural aging. The fracture surface characteristics of the failed parts showed that voids nucleate at the interface between intermetallic particles and matrix, and a dimple rupture fracture mode was identified under all heat-treatment conditions. Under O-temper condition, due to precipitation of particles along the grain boundary, an intergranular dimple rupture was observed. Finally, Energy dispersive x-ray (EDX) and electron backscattered diffraction (EBSD) were used to investigate the possible effects of the heat treatment and the deformation on the changes in the composition of

  1. Single Point Incremental Forming of an Aged AL-Cu-Mg Alloy: Influence of Pre-heat Treatment and Warm Forming

    NASA Astrophysics Data System (ADS)

    Mohammadi, Amirahmad; Qin, Ling; Vanhove, Hans; Seefeldt, Marc; Van Bael, Albert; Duflou, Joost R.

    2016-04-01

    This research is aimed at enhancing the poor room temperature formability of heat-treatable aluminum alloy AA2024-T3, without deterioration of its post-forming properties. For this purpose, the influences of different heat-treatment conditions as well as warm forming on the single point incremental forming formability and post-forming properties of this material were investigated. Thermal pre-treatments were consisting of annealing (O-temper), solution treating and quenching (W-temper), and solution heat treating, quenching, and then cold working (T-temper). The formability results as well as forming forces of pre-heat-treated sheets were compared to those of the warm forming process results carried out using a laser-assisted single point incremental forming (LASPIF) setup. The post-forming properties of SPIF-formed parts were analyzed by hardness testing. The maximum forming angles of the blank formed under O-temper and W-temper conditions showed, respectively, 41 and 32% increases compared to the one under T-temper condition. LASPIF forming of this material at a temperature of about 360 °C resulted in 41% improvement in the maximum forming angle with respect to parts formed at room temperature from the T-temper sheet. The hardness of the material reduced significantly after annealing, while SPIF parts formed from W-temper blanks and under LASPIF condition regained their hardness after natural aging. The fracture surface characteristics of the failed parts showed that voids nucleate at the interface between intermetallic particles and matrix, and a dimple rupture fracture mode was identified under all heat-treatment conditions. Under O-temper condition, due to precipitation of particles along the grain boundary, an intergranular dimple rupture was observed. Finally, Energy dispersive x-ray (EDX) and electron backscattered diffraction (EBSD) were used to investigate the possible effects of the heat treatment and the deformation on the changes in the composition of

  2. Plutonium focus area: Technology summary

    SciTech Connect

    1996-03-01

    To ensure research and development programs focus on the most pressing environmental restoration and waste management problems at the U.S. Department of Energy (DOE), the Assistant Secretary for the Office of Environmental Management (EM) established a working group in August 1993 to implement a new approach to research and technology development. As part of this approach, EM developed a management structure and principles that led to creation of specific focus areas. These organizations were designed to focus scientific and technical talent throughout DOE and the national scientific community on major environmental restoration and waste management problems facing DOE. The focus area approach provides the framework for inter-site cooperation and leveraging of resources on common problems. After the original establishment of five major focus areas within the Office of Technology Development (EM-50), the Nuclear Materials Stabilization Task Group (NMSTG, EM-66) followed EM-50`s structure and chartered the Plutonium Focus Area (PFA). NMSTG`s charter to the PFA, described in detail later in this book, plays a major role in meeting the EM-66 commitments to the Defense Nuclear Facilities Safety Board (DNFSB). The PFA is a new program for FY96 and as such, the primary focus of revision 0 of this Technology Summary is an introduction to the Focus Area; its history, development, and management structure, including summaries of selected technologies being developed. Revision 1 to the Plutonium Focus Area Technology Summary is slated to include details on all technologies being developed, and is currently planned for release in August 1996. The following report outlines the scope and mission of the Office of Environmental Management, EM-60, and EM-66 organizations as related to the PFA organizational structure.

  3. Forensic investigation of plutonium metal: a case study of CRM 126

    DOE PAGESBeta

    Byerly, Benjamin L.; Stanley, Floyd; Spencer, Khal; Colletti, Lisa; Garduno, Katherine; Kuhn, Kevin; Lujan, Elmer; Martinez, Alex; Porterfield, Donivan; Rim, Jung; et al

    2016-06-27

    In our study, a certified plutonium metal reference material (CRM 126) with a known production history is examined using analytical methods that are commonly employed in nuclear forensics for provenancing and attribution. Moreover, the measured plutonium isotopic composition and actinide assay are consistent with values reported on the reference material certificate. Model ages from U/Pu and Am/Pu chronometers agree with the documented production timeline. Finally, these results confirm the utility of these analytical methods and highlight the importance of a holistic approach for forensic study of unknown materials.

  4. Plutonium residue recovery (PuRR) project: Quarterly progress report, October--December 1988

    SciTech Connect

    Alire, R.M.; Coops, M.S.; Gregg, D.W.; Hickman, R.G.; Landrum, J.H.; Pittenger, L.C.; Johnson, G.K.; Johnson, I.; Mulcahey, T.P.; Piece, R.D.

    1989-02-01

    Substantial progress was made in several areas of the PuRR (plutonium residue recovery) program during the quarter. Criteria were developed for selecting process options, with the goal of process simplification. A modified flowsheet and material balance were selected that reflect these priorities. Efforts to effect a front-end separation by sedimentation were not successful. Experimental liquid-liquid extractions from alloys to salts based on valence change were performed. Results ranged from fair to good, but experimental equipment materials problems occurred. Also, substantial interference from the large excess of tramp metals present, which influence plutonium activity, suggested alternate approaches should be given priority. Estimates of the high-temperature thermodynamic functions of americium chlorides were calculated for the first time. 11 refs., 3 figs., 10 tabs.

  5. Design-only conceptual design report: Plutonium Immobilization Plant

    SciTech Connect

    DiSabatino, A A

    2000-05-01

    This design-only conceptual design report was prepared to support a funding request by the Department of Energy Office of Fissile Materials Disposition for engineering and design of the Plutonium Immobilization Plant, which will be used to immobilize up to 50 tonnes of surplus plutonium. The Plutonium Immobilization Plant will be located at the Savannah River Site pursuant to the Surplus Plutonium Disposition Final Environmental Impact Statement Record of Decision, January 4, 2000. This document reflects a new facility using the ceramic immobilization technology and the can-in-canister approach. The Plutonium Immobilization Plant accepts plutonium oxide from pit conversion and plutonium and plutonium oxide from non-pit sources and, through a ceramic immobilization process, converts the plutonium into mineral-like forms that are subsequently encapsulated within a large canister of high-level waste glass. The final immobilized product must make the plutonium as inherently unattractive and inaccessible for use in nuclear weapons as the plutonium in spent fuel from commercial reactors; it must also be suitable for geologic disposal. Plutonium immobilization at the Savannah River Site uses a new building, the Plutonium Immobilization Plant, which will receive and store feed materials, convert non-pit surplus plutonium to an oxide form suitable for the immobilization process, immobilize the plutonium oxide in a titanate-based ceramic form, place cans of the plutonium-ceramic forms into magazines, and load the magazines into a canister. The existing Defense Waste Processing Facility is used for the pouring of high-level waste glass into the canisters. The Plutonium Immobilization Plant uses existing Savannah River Site infrastructure for analytical laboratory services, waste handling, fire protection, training, and other support utilities and services. This design-only conceptual design report also provides the cost for a Plutonium Immobilization Plant which would process

  6. International shipment of plutonium by air

    SciTech Connect

    Mercado, J.E.; McGrogan, J.P.

    1995-05-01

    In support of the United States (US) Government`s decision to place excess plutonium oxide at the US Department of Energy`s (DOE) Hanford Site under International Atomic Energy Agency (IAEA) safeguards, the Department of State notified the Congress that a plutonium storage vault at the Plutonium Finishing Plant at the Hanford Site would be added to the eligible facilities list. As part of the preparations to transfer the plutonium oxide under IAEA safeguards, samples of the powder were taken from the inventory to be shipped to the IAEA headquarters in Vienna, Austria, for laboratory analysis. The analysis of these samples was of high priority, and the IAEA requested that the material be shipped by aircraft, the most expeditious method.

  7. IMPROVED PROCESS OF PLUTONIUM CARRIER PRECIPITATION

    DOEpatents

    Faris, B.F.

    1959-06-30

    This patent relates to an improvement in the bismuth phosphate process for separating and recovering plutonium from neutron irradiated uranium, resulting in improved decontamination even without the use of scavenging precipitates in the by-product precipitation step and subsequently more complete recovery of the plutonium in the product precipitation step. This improvement is achieved by addition of fluomolybdic acid, or a water soluble fluomolybdate, such as the ammonium, sodium, or potassium salt thereof, to the aqueous nitric acid solution containing tetravalent plutonium ions and contaminating fission products, so as to establish a fluomolybdate ion concentration of about 0.05 M. The solution is then treated to form the bismuth phosphate plutonium carrying precipitate.

  8. Pulmonary carcinogenesis from plutonium-containing particles

    SciTech Connect

    Thomas, R.G.; Smith, D.M.; Anderson, E.C.

    1980-01-01

    Plutonium administered as an alpha radiation source to the respiratory tracts of Syrian hamsters has resulted in various incidences of neoplasia. Adenomas are the primary lung tumor observed, but adenocarcinomas are also prevalent.

  9. SEPARATION OF URANIUM, PLUTONIUM, AND FISSION PRODUCTS

    DOEpatents

    Spence, R.; Lister, M.W.

    1958-12-16

    Uranium and plutonium can be separated from neutron-lrradiated uranium by a process consisting of dissolvlng the lrradiated material in nitric acid, saturating the solution with a nitrate salt such as ammonium nitrate, rendering the solution substantially neutral with a base such as ammonia, adding a reducing agent such as hydroxylamine to change plutonium to the trivalent state, treating the solution with a substantially water immiscible organic solvent such as dibutoxy diethylether to selectively extract the uranium, maklng the residual aqueous solutlon acid with nitric acid, adding an oxidizing agent such as ammonlum bromate to oxidize the plutonium to the hexavalent state, and selectlvely extracting the plutonium by means of an immlscible solvent, such as dibutoxy dlethyletber.

  10. Interaction between stainless steel and plutonium metal

    SciTech Connect

    Dunwoody, John T; Mason, Richard E; Freibert, Franz J; Willson, Stephen P; Veirs, Douglas K; Worl, Laura A; Archuleta, Alonso; Conger, Donald J

    2010-01-01

    Long-term storage of excess plutonium is of great concern in the U.S. as well as abroad. The current accepted configuration involves intimate contact between the stored material and an iron-bearing container such as stainless steel. While many safety scenario studies have been conducted and used in the acceptance of stainless steel containers, little information is available on the physical interaction at elevated temperatures between certain forms of stored material and the container itself. The bulk of the safety studies has focused on the ability of a package to keep the primary stainless steel containment below the plutonium-iron eutectic temperature of approximately 410 C. However, the interactions of plutonium metal with stainless steel have been of continuing interest. This paper reports on a scoping study investigating the interaction between stainless steel and plutonium metal in a pseudo diffusion couple at temperatures above the eutectic melt-point.

  11. Plutonium-238 processing at Savannah River Plant

    SciTech Connect

    Burney, G.A.

    1983-01-01

    Plutonium-238 is produced by irradiating NpO/sub 2/-Al cermet slugs or tubes with neutrons. The neptunium-237 is produced as a by-product when natural or enriched uranium is irradiated with neutrons. The neptunium is separated by solvent extraction and ion exchange and precipitated as neptunium oxalate. Neptunium oxalate is calcined to neptunium oxide and fabricated into targets for irradiation. The irradiation conditions are controlled to produce plutonium with 80 to 90 wt % /sup 238/Pu.

  12. PLUTONIUM CARRIER METATHESIS WITH ORGANIC REAGENT

    DOEpatents

    Thompson, S.G.

    1958-07-01

    A method is described for converting a plutonium containing bismuth phosphate carrier precipitate Into a compositton more readily soluble in acid. The method consists of dissolving the bismuth phosphate precipitate in an aqueous solution of alkali metal hydroxide, and adding one of a certaia group of organic compounds, e.g., polyhydric alcohols or a-hydrorycarboxylic acids. The mixture is then heated causiing formation of a bismuth hydroxide precipitate containing plutonium which may be readily dissolved in nitric acid for further processing.

  13. Improved plutonium identification and characterization results with NaI(Tl) detector using ASEDRA

    NASA Astrophysics Data System (ADS)

    Detwiler, R.; Sjoden, G.; Baciak, J.; LaVigne, E.

    2008-04-01

    The ASEDRA algorithm (Advanced Synthetically Enhanced Detector Resolution Algorithm) is a tool developed at the University of Florida to synthetically enhance the resolved photopeaks derived from a characteristically poor resolution spectra collected at room temperature from scintillator crystal-photomultiplier detector, such as a NaI(Tl) system. This work reports on analysis of a side-by-side test comparing the identification capabilities of ASEDRA applied to a NaI(Tl) detector with HPGe results for a Plutonium Beryllium (PuBe) source containing approximately 47 year old weapons-grade plutonium (WGPu), a test case of real-world interest with a complex spectra including plutonium isotopes and 241Am decay products. The analysis included a comparison of photopeaks identified and photopeak energies between the ASEDRA and HPGe detector systems, and the known energies of the plutonium isotopes. ASEDRA's performance in peak area accuracy, also important in isotope identification as well as plutonium quality and age determination, was evaluated for key energy lines by comparing the observed relative ratios of peak areas, adjusted for efficiency and attenuation due to source shielding, to the predicted ratios from known energy line branching and source isotopics. The results show that ASEDRA has identified over 20 lines also found by the HPGe and directly correlated to WGPu energies.

  14. A theoretical investigation of mixing thermodynamics, age-hardening potential, and electronic structure of ternary M11-xM2xB2 alloys with AlB2 type structure

    NASA Astrophysics Data System (ADS)

    Alling, B.; Högberg, H.; Armiento, R.; Rosen, J.; Hultman, L.

    2015-05-01

    Transition metal diborides are ceramic materials with potential applications as hard protective thin films and electrical contact materials. We investigate the possibility to obtain age hardening through isostructural clustering, including spinodal decomposition, or ordering-induced precipitation in ternary diboride alloys. By means of first-principles mixing thermodynamics calculations, 45 ternary M11-xM2xB2 alloys comprising MiB2 (Mi = Mg, Al, Sc, Y, Ti, Zr, Hf, V, Nb, Ta) with AlB2 type structure are studied. In particular Al1-xTixB2 is found to be of interest for coherent isostructural decomposition with a strong driving force for phase separation, while having almost concentration independent a and c lattice parameters. The results are explained by revealing the nature of the electronic structure in these alloys, and in particular, the origin of the pseudogap at EF in TiB2, ZrB2, and HfB2.

  15. A theoretical investigation of mixing thermodynamics, age-hardening potential, and electronic structure of ternary M11–xM2xB2 alloys with AlB2 type structure

    PubMed Central

    Alling, B.; Högberg, H.; Armiento, R.; Rosen, J.; Hultman, L.

    2015-01-01

    Transition metal diborides are ceramic materials with potential applications as hard protective thin films and electrical contact materials. We investigate the possibility to obtain age hardening through isostructural clustering, including spinodal decomposition, or ordering-induced precipitation in ternary diboride alloys. By means of first-principles mixing thermodynamics calculations, 45 ternary M11–xM2xB2 alloys comprising MiB2 (Mi = Mg, Al, Sc, Y, Ti, Zr, Hf, V, Nb, Ta) with AlB2 type structure are studied. In particular Al1–xTixB2 is found to be of interest for coherent isostructural decomposition with a strong driving force for phase separation, while having almost concentration independent a and c lattice parameters. The results are explained by revealing the nature of the electronic structure in these alloys, and in particular, the origin of the pseudogap at EF in TiB2, ZrB2, and HfB2. PMID:25970763

  16. Plutonium: The first 50 years. United States plutonium production, acquisition, and utilization from 1944 through 1994

    SciTech Connect

    1996-02-01

    The report contains important newly declassified information regarding the US production, acquisition, and removals of plutonium. This new information, when combined with previously declassified data, has allowed the DOE to issue, for the first time, a truly comprehensive report on the total DOE plutonium inventory. At the December 7, 1993, Openness Press Conference, the DOE declassified the plutonium inventories at eight locations totaling 33.5 metric tons (MT). This report declassifies the remainder of the DOE plutonium inventory. Newly declassified in this report is the quantity of plutonium at the Pantex Site, near Amarillo, Texas, and in the US nuclear weapons stockpile of 66.1 MT, which, when added to the previously released inventory of 33.5 MT, yields a total plutonium inventory of 99.5 MT. This report will document the sources which built up the plutonium inventory as well as the transactions which have removed plutonium from that inventory. This report identifies four sources that add plutonium to the DOE/DoD inventory, and seven types of transactions which remove plutonium from the DOE/DoD inventory. This report also discusses the nuclear material control and accountability system which records all nuclear material transactions, compares records with inventory and calculates material balances, and analyzes differences to verify that nuclear materials are in quantities as reported. The DOE believes that this report will aid in discussions in plutonium storage, safety, and security with stakeholders as well as encourage other nations to declassify and release similar data. These data will also be available for formulating policies with respect to disposition of excess nuclear materials. The information in this report is based on the evaluation of available records. The information contained in this report may be updated or revised in the future should additional or more detailed data become available.

  17. Plutonium Finishing Plant safety evaluation report

    SciTech Connect

    Not Available

    1995-01-01

    The Plutonium Finishing Plant (PFP) previously known as the Plutonium Process and Storage Facility, or Z-Plant, was built and put into operation in 1949. Since 1949 PFP has been used for various processing missions, including plutonium purification, oxide production, metal production, parts fabrication, plutonium recovery, and the recovery of americium (Am-241). The PFP has also been used for receipt and large scale storage of plutonium scrap and product materials. The PFP Final Safety Analysis Report (FSAR) was prepared by WHC to document the hazards associated with the facility, present safety analyses of potential accident scenarios, and demonstrate the adequacy of safety class structures, systems, and components (SSCs) and operational safety requirements (OSRs) necessary to eliminate, control, or mitigate the identified hazards. Documented in this Safety Evaluation Report (SER) is DOE`s independent review and evaluation of the PFP FSAR and the basis for approval of the PFP FSAR. The evaluation is presented in a format that parallels the format of the PFP FSAR. As an aid to the reactor, a list of acronyms has been included at the beginning of this report. The DOE review concluded that the risks associated with conducting plutonium handling, processing, and storage operations within PFP facilities, as described in the PFP FSAR, are acceptable, since the accident safety analyses associated with these activities meet the WHC risk acceptance guidelines and DOE safety goals in SEN-35-91.

  18. PLUTONIUM FINISHING PLANT (PFP) STABILIZATION & PACKAGING PROJECT

    SciTech Connect

    GERBER, M.S.

    2004-01-14

    Fluor Hanford is pleased to submit the Plutonium Finishing Plant (PFP) Stabilization and Packaging Project (SPP) for consideration by the Project Management Institute as Project of the Year for 2004. The SPP thermally stabilized and/or packaged nearly 18 metric tons (MT) of plutonium and plutonium-bearing materials left in PFP facilities from 40 years of nuclear weapons production and experimentation. The stabilization of the plutonium-bearing materials substantially reduced the radiological risk to the environment and security concerns regarding the potential for terrorists to acquire the non-stabilized plutonium products for nefarious purposes. The work was done In older facilities which were never designed for the long-term storage of plutonium, and required working with materials that were extremely radioactive, hazardous, pyrophoric, and In some cases completely unique. I n some Instances, one-of-a-kind processes and equipment were designed, installed, and started up. The SPP was completed ahead of schedule, substantially beating all Interim progress milestone dates set by the Defense Nuclear Facilities Safety Board (DNFSB) and in the Hanford Site's Federal Facility Agreement and Consent Order (Tri-Party Agreement or TPA), and finished $1-million under budget.

  19. Method of producing superplastic alloys and superplastic alloys produced by the method

    NASA Technical Reports Server (NTRS)

    Troeger, Lillianne P. (Inventor); Starke, Jr., Edgar A. (Inventor); Crooks, Roy (Inventor)

    2002-01-01

    A method for producing new superplastic alloys by inducing in an alloy the formation of precipitates having a sufficient size and homogeneous distribution that a sufficiently refined grain structure to produce superplasticity is obtained after subsequent PSN processing. An age-hardenable alloy having at least one dispersoid phase is selected for processing. The alloy is solution heat-treated and cooled to form a supersaturated solid solution. The alloy is plastically deformed sufficiently to form a high-energy defect structure useful for the subsequent heterogeneous nucleation of precipitates. The alloy is then aged, preferably by a multi-stage low and high temperature process, and precipitates are formed at the defect sites. The alloy then is subjected to a PSN process comprising plastically deforming the alloy to provide sufficient strain energy in the alloy to ensure recrystallization, and statically recrystallizing the alloy. A grain structure exhibiting new, fine, equiaxed and uniform grains is produced in the alloy. An exemplary 6xxx alloy of the type capable of being produced by the present invention, and which is useful for aerospace, automotive and other applications, is disclosed and claimed. The process is also suitable for processing any age-hardenable aluminum or other alloy.

  20. Formation and evolution of intermetallic nanoparticles and vacancy defects under irradiation in Fesbnd Nisbnd Al ageing alloy characterized by resistivity measurements and positron annihilation

    NASA Astrophysics Data System (ADS)

    Druzhkov, A. P.; Danilov, S. E.; Perminov, D. A.; Arbuzov, V. L.

    2016-08-01

    In this paper, we study the effects of intermetallic nanoparticles like Ni3Al on the evolution of vacancy defects in the fcc Fesbnd Nisbnd Al alloy under electron irradiation using positron annihilation spectroscopy. Electrical resistivity measurements have been used as a testing method for characterizing the evolution in the underlying precipitate microstructure due to heat treatment and irradiation. It was shown that the nanosized (∼4.5 nm) intermetallic precipitates homogeneously distributed in the alloy matrix caused a several-fold decrease in the accumulation of vacancies as compared to their accumulation in the pre-quenched alloy. This effect was enhanced with the irradiation temperature. The irradiation-induced growth of intermetallic nanoparticles was also observed in the pre-quenched Fesbnd Nisbnd Al alloy under irradiation at 573 K. Thus, resistivity measurement and positron confinement in ultrafine intermetallic particles, which we revealed earlier, provided the control over the evolution of coherent precipitates, along with vacancy defects, during irradiation and annealing.