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Gamma Rays from the Interaction of 14-Mev Neutrons with Beryllium

Description: Abstract: "The cross section for the Be-9(n, t')Li-7*-->Li-7 + Y(0.477 Mev) reaction has been measured in the vicinity of 14 Mev by detecting the gamma-rays at scattering angles from 30 to 150 degrees. A time-of-flight technique was used to distinguish the gamma-rays from the high neutron background. The cross section drops from 20 mb at 13.6 Mev to 10 mb at 14.1 Mev and then rises to 30 mb at 14.7 Mev."
Date: June 9, 1959
Creator: Benveniste, J.; Mitchell, A. C.; Schrader, C. D. & Zenger, J. H.
Partner: UNT Libraries Government Documents Department


Description: The thermal conductivities of Al-Li alloys containing up to 8 wt.% lithium were determined at 125 to 260 deg C. The addition of lithium to aluminum sharply reduces the conductivity from 0.60 cal/(sec) deg C)(cm) for pure aluminum to 0.22 cal/(sec)( deg C)(cm) for 2 wt.% alloys; further addition linearly and more gradually decreases the conductivity to 0.16 cal/(sec)( deg C)(cm) for a 7.9 wt.% alloy. (auth)
Date: April 1, 1960
Creator: Costas, L.P.
Partner: UNT Libraries Government Documents Department


Description: Brillouin polyhedra for the intermetallic compounds of lithium and lead were determined using the zone theory. From these determinations, predictions and explanations of some electromagmetic and structural properties of the intermetallic compounds were made. (For Part IV see UCRL-4973.) (C.J.G.)
Date: November 13, 1959
Creator: Ramsey, W J & Jepson, J O
Partner: UNT Libraries Government Documents Department


Description: Phase transfer of Pr by electrolysis at a lithium amalgam cathode was found to be linear with time for fixed electrolysis conditions. The rate of electrolysis of Pr decreased with increasing lithium citrate concentration. Extraction of Pm from Pm--Gd mixtures with saturated lithium amalgam was found to vary with virtually any change in electrolyte composition. The Pm extraction was first order with respect to Pm concentration, but the extraction rate decreased with increasing excess citrate concentration. The presence of Gd did not affect the extraction of Pm very much at Gd concentrations less than 0.1 M, but at higher concentrations of Gd the amount of Pm extracted was diminished. The results indicate that the exchange reactions are very fast and it may be possible to interpret rate data in terms of equilibria in the electrolyte phase. (auth)
Date: January 1, 1963
Creator: Onstott, E.I.; Smyrl, W.H. & Macander, R.F.
Partner: UNT Libraries Government Documents Department

A method for treating electrolyte to remove Li{sub 2}O

Description: Electrorefining has been used in processes for recovering uranium and plutonium metals from spent nuclear fuel. The electrorefining is performed in an electrochemical cell in which the chopped fuel elements from the reactor forms the anode, the electrolyte, preferably, is the fused eutectic salt of the LiCl-KCl which contain UCl{sub 3} and PuCl{sub 3}. Purified metal collected at the cathode collects at the bottom of the cell. This invention provides a method for removing lithium oxide from the electrolyte salt, with the end formation of a solid lithium-aluminium alloy.
Date: April 1, 1998
Creator: Tomczuk, Z.; Miller, W.E.; Johnson, G.K. & Willit, J.L.
Partner: UNT Libraries Government Documents Department

Intermetallic insertion anodes for lithium batteries.

Description: Intermetallic alloys have been investigated for many years as anode materials for lithium batteries and, more recently, as alternative electrodes to carbon, because of several intrinsic advantages including high capacity and safety. Some of the most studied alloys utilize tin as the active component because of its high theoretical capacity (996 mAh/g) and its slightly higher operating voltage (<400 mV) compared to metallic lithium. To date, the use of binary lithium alloys as anodes has been limited to the select number of main group elements (e.g. Sn) that can be lithiated at an appropriate voltage with acceptable kinetics. A major disadvantage of binary Li{sub x}M alloy systems is that major phase changes occur during the electrochemical cycling of lithium. Severe volume expansion and contraction of the metal matrix, which limit the cycle life of the lithium cell, normally accompany these phase changes. The. most successful approach to overcoming this limitation has been the use of intermetallic alloys MM{prime} consisting of two (or more) metals, at least one of which is an ''active'' alloying element (M) and the other an ''inactive'' (M{prime}) element. During the reaction with lithium, such a system breaks up into regions of Li{sub x}M and inactive M{prime}. In our work, we have extended the concept of intermetallic electrodes to include topotactic reactions in which the intermetallic compound provides a host structure for lithium.
Date: July 19, 1999
Creator: Johnson, C. S.; Kahaian, A. J.; Kepler, K. D.; Scott, M.; Thackerary, M. M. & Vaughey, J.
Partner: UNT Libraries Government Documents Department

Calculations of nonspherically averaged charge densities for subtitutionally disordered alloys

Description: Based on screening transformations of muffin-tin orbitals introduced by Andersen et al. [Phys. Rev. Lett. 53, 2571 (1984)], we have developed a formalism for calculating the non-spherically averaged charge densities of substitutionally disordered alloys using the Korringa-Kohn-Rostoker coherent potential approximation (KKR CPA) method in the atomic-sphere approximation (ASA). We have validated our method by calculating charge densities for ordered structures, where we find that our approach yields charge densities that are essentially indistinguishable from the results of full-potential methods. For substitutionally disordered alloys, where full-potential methods have not been implemented so far, our approach can be used to calculate reliable non-spherically averaged charge densities from spherically symmetric one-electron potentials obtained from the KKR-ASA CPA. We report on our study of differences in charge denisty between ordered AlLi in L1{sub o} phase and substitutionally disordered Al{sub 0.5}Li{sub 0.5} on face-centered cubic lattice.
Date: February 1, 1994
Creator: Singh, P. P. & Gonis, A.
Partner: UNT Libraries Government Documents Department

Laminated metal composite formed from low flow stress layers and high flow stress layers using flow constraining elements and method of making same

Description: This invention relates to a laminated metal composite, comprising alternating layers of low flow stress material and high flow stress material, and formed using flow constraining elements around each low flow stress layer; and a method of making same. A composite is a combination of at least two chemically distinct materials with a distinct interface separating the two materials. A metal matrix composite (MMC) is a composite material composed of a metal and a nonmetallic reinforcing agent such as silicon carbide (SiC) or graphite in continuous or discontinuous fiber, whisker, or discrete particulate form. A laminate is a material composed of several bonded layers. It is possible to have a laminate composed of multi-layers of a single type of material bonded to each other. However, such a laminate would not be considered to be a composite. The term {open_quotes}laminated metal composite{close_quotes} (LMC), as used herein, is intended to include a structural material composed of: (1) layers of metal or metal alloys interleaved with (2) a different metal, a metal alloy, or a metal matrix composite (MMC) containing strengthening agents.
Date: December 31, 1994
Creator: Syn, C.K. & Lesuer, D.R.
Partner: UNT Libraries Government Documents Department

Microstructure-strength relationships of heavily deformed magnesium-lithium composites containing steel fibers

Description: The successful development of deformation-processed metal-metal composites (DMMC) offers the potential for ductile, high-strength structural materials with high-temperature stability. An infiltration casting process was used to permeate steel wool preforms with molten magnesium-lithium (Mg-Li) alloys. The selected matrix alloys were hexagonal close packed (HCP) Mg-4wt%Li or body centered cubic (BCC) Mg-12wt%Li; the low carbon steel wool fibers were predominantly BCC ferrite. These cast HCP/BCC and BCC/BCC composites were deformed by rolling or by extrusion and swaging. Mechanical properties, microstructure, and texture development of the composites were characterized at various levels of deformation. The HCP/BCC composites had limited formability at temperatures up to 400 C while the BCC/BCC composites had excellent formability during sheet rolling at room temperature but limited formability during swaging at room temperature. The tensile strengths of these HCP/BCC and BCC/BCC composite materials increased moderately with deformation, though less than predicted from rule of mixtures (ROM) calculations. The microstructure was characterized to correlate the filament size to the deformation strain and mechanical properties of the composite material. Stereological measurements of the filament size were used to adjust ROM calculations to reflect the actual deformation strain in the fibers. However, the experimental strengths of these composite materials were still less than ROM predictions, possibly due to the presence of considerably large fibers. Of the many models used to describe the strengthening observed in DMMC materials, the Hall-Petch relationship adequately described the experimental data. Texture development was also characterized to explain the deformation characteristics of the composite materials. Chapters 2, 3 and 4 are not included here. They are being processed separately.
Date: October 8, 1997
Creator: Jensen, J.
Partner: UNT Libraries Government Documents Department

Proceedings of the International Workshop on High-Temperature Molten Salt Batteries : April 16-18, 1986

Description: This three-day workshop on high-temperature molten salt batteries provided an excellent opportunity to bring together those who are actively involved in the research and development of rechargeable, molten-salt battery systems. Twenty-six papers are presented in three sessions, titled: basic properties of molten salt battery systems, engineering development of lithium-alloy/metal sulfide batteries; and research and development in molten salt systems. This format has been retained in the publication of the workshop papers, with each part having separate pagination.
Date: 1986
Creator: McLarnon, Frank
Partner: UNT Libraries Government Documents Department

Atomistic Simulations of Deformation Mechanisms in Ultra-Light Weight Mg-Li Alloys

Description: Mg alloys have spurred a renewed academic and industrial interest because of their ultra-light-weight and high specific strength properties. Hexagonal close packed Mg has low deformability and a high plastic anisotropy between basal and non-basal slip systems at room temperature. Alloying with Li and other elements is believed to counter this deficiency by activating non-basal slip by reducing their nucleation stress. In this work I study how Li addition affects deformation mechanisms in Mg using atomistic simulations. In the first part, I create a reliable and transferable concentration dependent embedded atom method (CD-EAM) potential for my molecular dynamics study of deformation. This potential describes the Mg-Li phase diagram, which accurately describes the phase stability as a function of Li concentration and temperature. Also, it reproduces the heat of mixing, lattice parameters, and bulk moduli of the alloy as a function of Li concentration. Most importantly, our CD-EAM potential reproduces the variation of stacking fault energy for basal, prismatic, and pyramidal slip systems that influences the deformation mechanisms as a function of Li concentration. This success of CD-EAM Mg-Li potential in reproducing different properties, as compared to literature data, shows its reliability and transferability. Next, I use this newly created potential to study the effect of Li addition on deformation mechanisms in Mg-Li nanocrystalline (NC) alloys. Mg-Li NC alloys show basal slip, pyramidal type-I slip, tension twinning, and two-compression twinning deformation modes. Li addition reduces the plastic anisotropy between basal and non-basal slip systems by modifying the energetics of Mg-Li alloys. This causes the solid solution softening. The inverse relationship between strength and ductility therefore suggests a concomitant increase in alloy ductility. A comparison of the NC results with single crystal deformation results helps to understand the qualitative and quantitative effect of Li addition in Mg on nucleation stress and fault ...
Date: May 2015
Creator: Karewar, Shivraj
Partner: UNT Libraries

Enhancing tensile ductility of a particulate-reinforced aluminum MMC by lamination with Mg-9% Li alloy

Description: A laminated metal composite has been made by press bonding alternating layers of a particulate-reinforced aluminum MMC, 6090/SiC/25p, and a Mg-9%Li alloy. The mechanical properties including tensile ductility were evaluated. The tensile ductility of the Al MMC was found to increase from 3.5% to 11.5%. In contrast to other laminates based on ultrahigh carbon, steel, the laminate of this study and other Al MMC laminates exhibited tensile yield strengths that did not follow the rule of averages. This is attributed to interlayer reaction products developed during processing of the Al MMC laminates.
Date: May 1995
Creator: Syn, C. K.; Lesuer, D. R. & Sherby, O. D.
Partner: UNT Libraries Government Documents Department

An anodic dissolution-based mechanism for the rapid cracking, ``pre-exposure`` phenomenon demonstrated by Al-Li-Cu alloys

Description: Al-Li-Cu alloys have been observed to fail in less than 24 hours after removal from a one week immersion in aerated 3.5 w/o NaCl solution. Anodic dissolution-based mechanisms proposed previously for this phenomenon have been amended based on further experiment and characterization of the rapid cracking process. Amendments are based on studies of the relative electrochemical behavior of the microstructural elements in the subgrain boundary region, time to failure SCC testing in a simulated crack solution, evolution of crack potential and pH with time, fractographic examination of failed samples, and X-ray diffraction of films passivating crack walls. Results suggest that an active path exists along subgrain boundaries that is comprised of the highly reactive T{sub 1} (Al{sub 2}CuLi) precipitate phase and a solute depleted zone that does not readily passivate when exposed to the crack environment. The matrix phase does appear to passivate in the crack environment thereby confining the crack to the subgrain boundary region. This active path is enabled when cracks are isolated from a bulk environment, but is disabled otherwise. Potential and pH conditions required for cracking are discussed as is the formation of a hydrotalcite Li{sub 2}[Al{sub 2}(OH){sub 6}]{sub 2}{center_dot}CO{sub 3}{center_dot}3H{sub 2}O film that appears to be responsible for passivating crack walls.
Date: December 31, 1993
Creator: Buchheit, R. G.; Wall, F. D.; Stoner, G. E. & Moran, J. P.
Partner: UNT Libraries Government Documents Department

Dynamic mechanical deformation of a SiC{sub p}/Al-Li (8090) composite

Description: The deformation behavior in compression of a silicon carbide particle-reinforced aluminum-lithium (8090) matrix composite, at strain rates in the range of 10{sup {minus}3} to 6500 s{sup {minus}1}, was investigated, and compared with that of unreinforced alloy samples. Dynamics strengthening in these composites was found to change depending on the direction of testing. These differences were attributed to differences in the orientation of the reinforcing particles. 4 refs, 5 figs.
Date: June 1, 1993
Creator: Vaidya, R. U. & Zurek, A. K.
Partner: UNT Libraries Government Documents Department


Description: Hydridable metal alloys are used at the Savannah River Site to process tritium. The goal of this work was to develop a mechanical alloying process as a low-cost option to produce these alloys on-site. High-speed milling at elevated temperatures has the potential to significantly reduce the time and cost of the mechanical alloying process. It was demonstrated that elemental metal powders can be alloyed in an attritor mill under argon. In order to form LaNi{sub 4.25}Al{sub 0.75} from elemental metals it was found that lanthanum and nickel must be alloyed prior to adding aluminum. It was also demonstrated that metal powders could be alloyed in the high-speed attritor with the temperature in the mill equilibrating at {approx}220 C. Optimization of the process parameters will require additional testing.
Date: November 30, 2006
Creator: Fox, K
Partner: UNT Libraries Government Documents Department

The Magnesium-28-Aluminum-28 System: An Aluminum-28 Generator

Description: A milking method was developed for the production of the short-lived Al/ sup 28/ for use in physiological experiments. A Mg/sup 28/ solution is obtained by the irradiation and purification of a Li/sup 6/Mg/sup 26/ alloy, and it is placed on a Dowex 50W column in the Na/sup +/ form and then washed with 1 N NaOH. The Al/sup 28/ is eluted in 10 to 30 sec by 1 N NaOH solution containing 0.5 mg/ ml of carrier Al. The half lives of Mg/sup 28/ and Al/sup 28/ were determined to be 20.88 plus or minus 0.06 hr and 2.238 plus or minus 0.006 min, respectively. (D.L.C.)
Date: March 15, 1963
Creator: Weiss, A. J. & Hillman, M.
Partner: UNT Libraries Government Documents Department

Calorimetric sensors for energy deposition measurements

Description: A calorimetric sensor with several novel design features has been developed. These sensors will provide an accurate sampling of thermal power density and energy deposition from proton beams incident on target components of accelerator-based systems, such as the Accelerator Production of Tritium Project (APT) and the Spallation Neutron Source (SNS). A small, solid slug (volume = 0.347 cc) of target material is suspended by kevlar fibers and surrounded by an adiabatic enclosure in an insulating vacuum canister of stainless steel construction. The slug is in thermal contact with a low-mass, calibrated, 100-k{Omega} thermistor. Power deposition caused by the passage of radiation through the slug is calculated from the rate of temperature rise of the slug. The authors have chosen slugs composed of Pb, Al, and LiAl.
Date: December 31, 1998
Creator: Langenbrunner, J.; Cooper, R. & Morgan, G.
Partner: UNT Libraries Government Documents Department

New Li-alloy electrode for Li-alloy/metal sulfide cells

Description: The present invention relates to electrodes for use in secondary electrochemical cells. More particularly, it concerns a method of making a negative electrode composition, the electrode composition made thereby and the secondary electrochemical cell containing the electrode, wherein the negative electrode composition includes a lithium alloy including silicon and nickel.
Date: December 31, 1994
Creator: Kaun, T.D.
Partner: UNT Libraries Government Documents Department

Electrically insulating coatings for V-Li self-cooled blanket in a fusion system

Description: The blanket system is one of the most important components in a fusion reactor because it has a major impact on both the economics and safety of fusion energy. The primary functions of the blanket in a deuterium/tritium-fueled fusion reactor are to convert the fusion energy into sensible heat and to breed tritium for the fuel cycle. The liquid-metal blanket concept requires an electrically insulating coating on the first-wall structural material to minimize the magnetohydrodynamic pressure drop that occurs during the flow of liquid metal in a magnetic field. Based on the thermodynamics of interactions between the coating and the liquid lithium on one side and the structural V-base alloy on the other side, several coating candidates are being examined to perform the insulating function over a wide range of temperatures and lithium chemistries.
Date: May 17, 2000
Creator: Natesan, K.; Reed, C. B.; Uz, M.; Park, J. H. & Smith, D. L.
Partner: UNT Libraries Government Documents Department