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in subjects: "Manganese Alloys"

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Positron Annihilation Spectroscopy and Small Angle Neutron Scattering Characterization of Nanostructural Features in Irradiated Fe-Cu-Mn Alloys

Radiation embrittlement of nuclear reactor pressure vessel steels results from a high number density of nanometer sized Cu-Mn-Ni rich precipitates (CRPs) and sub-nanometer matrix features, thought to be vacancy-solute cluster complexes (VSC). However, questions exist regarding both the composition of the precipitates and the defect character and composition of the matrix features. We present results of positron annihilation spectroscopy (PAS) and small angle neutron scattering (SANS) characteri… more

Date: January 1, 2001

Creator: Wirth, B D; Asoka-Kumar, P; Howell, R H; Odette, G R & Sterne, P A

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Operation of a Tritium Glovebox Clean-Up System Using Zirconium Manganese Iron and Zirconium Two Iron Metal Getters

A metal hydride-based tritium clean-up system has been successfully operated for more than four years on an 11 m{sup 3} helium/nitrogen glovebox which was used for handling metal tritide powders. The clean-up system consists of two beds: (1) a Zr-Mn-Fe (in a 10% by weight Al binder, SAES ST909) bed operating at 675 C followed by (2) a Zr{sub 2}Fe (SAES ST198) bed operating at 250 C. The Zr-Mn-Fe bed serves to condition the gas stream by cracking hydrogenous impurities (such as H{sub 2}O and hyd… more

Date: August 1, 2000

Creator: Larson, E. & Cook, K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Correlating radiation exposure with embrittlement: Comparative studies of electron- and neutron-irradiated pressure vessel alloys

Comparative experiments using high energy (10 MeV) electrons and test reactor neutrons have been undertaken to understand the role that primary damage state has on hardening (embrittlement) induced by irradiation at 300 C. Electrons produce displacement damage primarily by low energy atomic recoils, while fast neutrons produce displacements from considerably higher energy recoils. Comparison of changes resulting from neutron irradiation, in which nascent point defect clusters can form in dense … more

Date: December 22, 1999

Creator: Alexander, D. E.; Rehn, L. E.; Odette, G. R.; Lucas, G. E.; Klingensmith, D. & Gragg, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Radiation embrittlement studies using anomalous small-angle x-ray scattering

Anomalous small angle x-ray scattering (ASAXS) was performed on an Fe-O.9 wt.% Cu-1.0 wt.% Mn alloy subjected to annealing or electron irradiation. ASAXS takes advantage of natural variations in the atomic scattering factor which exist at energies very near an element's x-ray absorption edge. By performing systematic SAXS experiments at energies near these absorption edges of the constituent alloy elements it is possible to vary the contrast of scattering centers containing the elements and in … more

Date: December 6, 1999

Creator: Alexander, D. E.; Kestel, B. J.; Seifert, S.; Jemian, P. R.; Odette, G. R.; Klingensmith, D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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PdMn and PdFe: New Materials for Temperature Measurement Near 2K

Interest in the critical dynamics of superfluid 4 He in microgravity conditions has motivated the development of new high resolution thermometry technol- ogy for use in space experiments near 2K. The current material commonly used as the temperature sensing element for high resolution thermometers (HRTs) is copper ammonium bromide [Cu(NH4)2Br42H20) or "CAB", which undergoes a ferromagnetic phase transition at 1.8K1. HRTs made from CAB have … more

Date: May 17, 1999

Creator: Adriaans, M. J.; Aselage, T. L.; Day, P. K.; Duncan, R. V.; Klemme, B. J. & Sergatskov, D. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Magnetic and magneto-topical properties of RMn{sub 6}Sn{sub 6} single crystals where R = Gd, Tb, Dy, Ho, Er, Tm, Lu

Single crystals of the ternary compounds RMn{sub 6}Sn{sub 6}, where R = Gd, Tb, Dy, Ho, Er, Tm, and Lu, have been prepared by the flux growth technique. All of the compounds have the HfFe{sub 6}Ge{sub 6} type crystal structure (space group P6/mmm), and the variation of the lattice parameters with lanthanide element exhibits the lanthanide contraction as well as evidence of crystal field effects. Measurements on the magnetic properties of TbMn{sub 6}Sn{sub 6} indicate that it orders ferrimagneti… more

Date: February 12, 1999

Creator: Clatterbuck, D.M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Surface structures of Al-Pd-Mn and Al-Cu-Fe icosahedral quasicrystals

In this dissertation, the author reports on the surface structure of i-Al-Pd-Mn twofold, threefold, fivefold and i-Al-Cu-Fe fivefold surfaces. The LEED studies indicate the existence of two distinct stages in the regrowth of all four surfaces after Ar{sup +} sputtering. In the first stage, upon annealing at relatively low temperature: 500K--800K (depending on different surfaces), a cubic phase appears. The cubic LEED patterns transform irreversibly to unreconstructed quasicrystalline patterns u… more

Date: February 12, 1999

Creator: Shen, Z.

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department

open access

PdMn and PdFe: New Materials for Temperature Measurement Near 2K

Interest in the critical dynamics of superfluid He in microgravity conditions has motivated the development of new high resolution thermometry technology for use in space experiments near 2K. The current material commonly used as the temperature sensing element for high resolution thermometers (HRTs) is copper ammonium bromide (Cu(NH{sub 4}){sub 2}Br{sub 4}2H{sub 2}O) or CAB, which undergoes a ferromagnetic phase transition at 1.8K. HRTs made from CAB have demonstrated low drift (<10fK/s) an… more

Date: February 1, 1999

Creator: Aselage, T. L.; Duncan, R. V.; Klemme, B. J.; Sergatskov, D. A.; Adriaans, M. J. & Day, P. K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Microstructural characterization of a Zr-Ti-Ni-Mn-V-Cr based AB{sub 2}-type battery alloy

Transmission Electron Microscopy (TEM), combined with X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) was employed to investigate a proprietary and multicomponent AB{sub 2} type Nickel-Metal Hydride (Ni-MH) battery alloy. This material was prepared by High Pressure Gas Atomization (HPGA) and examined in both the as-atomized and heat treated condition. TEM examination showed a heavily faulted dendritic growth structure in as-atomized powder. Selected Area Diffraction (SAD) showed … more

Date: January 1, 1999

Creator: Shi, Zhan

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department

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First-principles exchange interactions between ferro and antiferromagnetic films: Co on NiMn, a case study

Heisenberg exchange parameters at the interface of antiferromagnetic NiMn with ferromagnetic Co are calculated from first-principles. The authors use a layer version of the Korringa-Kohn-Rostocker multiple scattering approach and an expression, which is based on the expansion of the band energy, to calculate the exchange parameters from the underlying electronic structure. For bulk systems, the parameter sets yield Curie temperatures that are in good agreement with experimental values. In the i… more

Date: December 31, 1997

Creator: Schulthess, T. C. & Butler, W. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Corrosion of AB{sub 5} metal hydride electrodes

Metal hydride electrodes are an attractive substitute for the cadmium electrode in Cd/Ni batteries because of their relatively benign environmental impact and higher energy density. However, even though MH{sub x}/Ni batteries are currently competitive in certain applications, their full potential as cheap, reliable, energy storage devices is not yet realized: a severe penalty has been incurred in storage capacity and materials costs in order to inhibit corrosion and attain acceptable electrode … more

Date: November 1, 1997

Creator: Adzic, G. D.; Johnson, J. R.; Mukerjee, S.; McBreen, J. & Reilly, J. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Modular hydride beds for mobile applications

Design, construction, initial testing and simple thermal modeling of modular, metal hydride beds have been completed. Originally designed for supplying hydrogen to a fuel cell on a mobile vehicle, the complete bed design consists of 8 modules and is intended for use on the Palm Desert Vehicle (PDV) under development at the Schatz Energy Center, Humbolt State University. Each module contains approximately 2 kg of a commercially available, low temperature, hydride-forming metal alloy. Waste heat … more

Date: August 1, 1997

Creator: Malinowski, M.E. & Stewart, K.D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Physical metallurgy and properties of TiNiSn and PtMnSb

The single crystals of TiNiSn and polycrystalline PtMnSb were grown by the flux and melt cooling method. Their lattice parameters and structures were determined by x-ray diffraction. The effect of impurities on the growth of TiNiSn single crystals was investigated. It was found that the concentration of chlorine plays a key role in determining the chemical composition of the phases that are formed. The heat capacity and magnetic susceptibility of TiNiSn was measured in a temperature range from … more

Date: January 10, 1997

Creator: Zhong, B.

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department

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Composition and function in AB{sub 5} hydride electrodes

Multicomponent AB, hydrides are attractive replacements for the cadmium electrode in nickel - cadmium batteries. This paper is concerned with the differential effects of Ni substitution by cobalt, Mn and Al upon electrode corrosion and capacity, using alloys having the generic composition of Al(NiCoMnAl){sub 5} and similar to those used for the preparation of commercial battery electrodes. The corrosion of metal hydride electrodes is determined by two factors, surface passivation due to the pre… more

Date: December 31, 1996

Creator: Adzic, G. D.; Johnson, J. R.; Mukerjee, S.; McBreen, J. & Reilly, J. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Creep fracture during solute-drag creep and superplastic deformation

Creep fracture behavior has been studied in Al-Mg and Al-Mg-Mn alloys undergoing solute-drag creep and in microduplex stainless steel undergoing both solute-drag creep and superplastic deformation. Failure in these materials is found to be controlled by two mechanisms, neck formation and cavitation. The mechanism of creep fracture during solute-drag creep in Al-Mg is found to change from necking-controlled fracture to cavitation-controlled fracture as Mn content is increased. Binary Al-Mg mater… more

Date: October 1, 1996

Creator: Taleff, E. M.; Lesuer, D. R.; Syn, C. K. & Henshall, G. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Charge-density wave and magnetic phase diagram of chromium alloys

The magnetic phase diagrams of all dilute Cr alloys can be explained by a simple theoretical model with coupled spin- and charge-density waves and a finite electron reservoir. If the charge-density wave and electron reservoir are sufficiently large, the paramagnetic to commensurate spin-density wave transition becomes strongly first order, as found in Cr{sub 1- x}Fe{sub x} and Cr{sub 1-x}Si{sub x} alloys. The observed discontinuity of the slope dT{sub N}/dx at the triple point and the bending o… more

Date: August 8, 1996

Creator: Fishman, R.S. & Jiang, X.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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de Haas-van Alphen experiments in pulsed magnetic fields

The powerful combination of de Haas-van Alphen effect and pulsed magnetic fields enables the study of the Fermi surface and the electronic properties of various materials of current interest. In this contribution I discuss experiments on CeB6, a heavy fermion, on YBa{sub 2}Cu{sub 3}Awe{sub 7-{delta}}, a high-Tc superconductor, and on A1{sub 7O}Pd{sub 2l.5}Mn{sub 8.5}, a quasicrystal. For each of these experiments I will point out the essential contribution of the pulsed magnetic field.

Date: July 1, 1996

Creator: Haanappel, E.G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Microstructural characterization of selected AEA/UCSB model FeCuMn alloys

A set of 22 model ferritic alloys was purchased as part of a collaborative research program by the AEA Harwell Laboratory and the University of California at Santa Barbara. Nine of these alloys were selected by the Oak Ridge National Laboratory for use in a series of ion irradiation experiments investigating dispersed barrier hardening. These nine alloys contain varying amounts of copper, manganese, titanium, carbon, and nitrogen. The alloys have been characterized by transmission electron micr… more

Date: June 1, 1996

Creator: Rice, P.M. & Stoller, R.E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Dynamical x-ray diffraction from an icosahedral Al-Pd-Mn quasicrystal

Primary extinction effects in diffraction from single grains of Al-Pd- Mn, and presumably many other FCI alloys, may be significant and should be corrected for prior to use of diffraction data in structural determinations. Probes based on dynamical diffraction effects, such as x-ray standing wave fluorescence, multiple beam interference, and x-ray transmission topographs, may now be used to study the bulk and surface structure of some quasicrystals. The observation of dynamical diffraction from… more

Date: April 23, 1996

Creator: Kycia, S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Neutron Diffraction Study of the Magnetic Structures of Cemn{Sub 2}Ge{Sub 2} and Cemn{Sub 2}Si{Sub 2}

The magnetic properties of the layered compounds of the form RMn{sub 2}X{sub 2} (R = Rare Earth, X = Si, Ge) have been thought to be sensitive to the intralayer Mn-Mn distance. Thus it has been reported that the Mn moments in CeMn{sub 2}Si{sub 2} are aligned antiferromagnetically (AF) below T{sub N} = 380K, while the Mn moments in CeMn{sub 2}Ge{sub 2} are ferromagnetic (FM) below T{sub C} = 316K. Recently, however, there has been some debate about the actual magnetic structures of this family o… more

Date: December 31, 1995

Creator: Fernandez-Baca, J. A.; Chakoumakos, B. C.; Hill, P. & Ali, N.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Electron irradiation-induced mechanical property changes in reactor pressure vessel alloys

High-energy electrons were used to study tensile property changes in simple Fe-Cu and Fe-Cu-Mn alloys irradiated at 288C. A comparison was made with neutron irradiation data on the same alloys. An apparent effect of alloy chemistry was observed in which the presence of Mn affected embrittlement differently for electron and neutron irradiation. Comparison of previous experimental studies with the present experimental results indicates that electrons may be more efficient than fast neutrons at pr… more

Date: November 1, 1995

Creator: Alexander, D. E.; Rehn, L. E.; Odette, G. R. & Lucas, G. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Investment cast AISI H13 tooling for automotive applications

While many techniques exist for production of soft tooling, for die casting there is limited recent experience with cast tooling. The most common US alloy used for manufacture of die casting tooling is wrought AISI H13. If the performance of the cast material is comparable to the wrought counterpart, the use of investment cast HI 3 tooling directly from patterns made via rapid prototyping is of considerable interest. A metallurgical study of investment cast H13 was conducted to evaluate the mec… more

Date: July 1, 1995

Creator: Maguire, M. C.; Baldwin, M. D.; Hochanadel, P. W. & Edwards, G. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Phase transformation and phonon anomalies in Ni{sub 2}MnGa

Inelastic neutron scattering experiments and transmission electron microscopy have been used to study a single crystal of the Ni{sub 2}MnGa shape memory Hustler alloy in a wide temperature range covering the parent phase (T>T{sub 1}=265 K), a recently discovered pemartensitic (T{sub 1}T>T{sub M}) and martensitic (T<T{sub M}=220 K) phase regions. A temperature-dependent anomaly in the TA{sub 2} phonon dispersion in the parent phase was observed and related to the phase transformations. The prema… more

Date: July 1, 1995

Creator: Zheludev, A.; Shapiro, S.M.; Wochner, P.; Schwartz, A.; Wall, M. & Tanner, L.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Al{sub 70}Pd{sub 21.5}Mn{sub 8.5}: A quasicrystal showing the de haas-van Alphen effect

We have measured the de Haas-van Alphen effect in the icosahedral quasicrystal Al{sub 70}Pd{sub 21.5}Mn{sub 8.5}. We have found two well-defined frequencies with the magnetic field parallel to a five-fold axis, and two different ones with the field parallel to a two-fold axis. On increasing the temperature, the amplitude of the oscillations substantially decreased, suggesting that the carriers have large masses.

Date: July 1, 1995

Creator: Haanappel, E. G.; Kycia, S. W.; Harmon, B. N.; Canfield, P. C.; Goldman, A. I.; Rabson, D. A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department