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in creator/contributor: "Embury, J."

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The influence of microstructural scale on the combination of strength and electrical resistivity in copper based composites

There are many engineering applications in which composite materials are required to satisfy two or more criteria regarding physical and mechanical properties. An example is the development of two-phase wires or tapes for the fabrication of coils for high field magnets. Simple diagrammatic representations can be developed which display the combinations of properties for a variety of materials in relation to design requirements. For a simple solenoid, these diagrams are based on the development … more

Date: December 31, 1995

Creator: Wood, J. T.; Embury, J. D. & Veron, M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

MATERIALS WITH COMPLEX ELECTRONIC/ATOMIC STRUCTURES

No Description Available.

Date: March 1, 2000

Creator: Chen, L. & Embury, J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Imaging through a multiple scattering medium

The existing theory of imaging through an aerosol medium, based on the small-angle approximation to radiative transfer, is extended to the general case of multiple scattering with an arbitrary degree of anisotropy. By applying the discrete-ordinates, finite-element radiation transport code TWOTRAN, we compute the modulation transfer function for a medium characterized by optical depth, single scattering albedo, and a symmetry parameter. An extended version of this investigation will appear in a… more

Date: January 1, 1984

Creator: Zardecki, A.; Gerstl, S.A.W. & Embury, J.F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Two-dimensional modeling of multiply scattered laser radiation in optically dense aerosols

The discrete ordinates finite element radiation transport code TWOTRAN is applied to describe the multiple scattering of a laser beam from a reflecting target. For a model scenario involving a 99% relative humidity rural aerosol, we compute the average intensity of the scattered radiation and correction factors to the Lambert-Beer law arising from multiple scattering. As our results indicate, two-dimensional x-y and r-z geometry modeling can reliably describe a realistic three-dimensional scena… more

Date: January 1, 1982

Creator: Zardecki, A.; Gerstl, S.A.W. & Embury, J.F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Dislocation accumulation at large plastic strains -- An approach to the theoretical strength of materials

The usual method of introducing engineers to the concept of dislocations and their role in plastic flow is to compare an estimate of the theoretical strength of solid (of order {micro}/30 where {micro} is the shear modulus) and the observed strength of either single crystals ({mu}/10{sup 4}) or practical engineering material such as structural steels where the yield stress in shear is of order {mu}/10{sup 3}. However, if one considers the problem in reverse, one can consider the accumulation of… more

Date: April 1, 1999

Creator: Embury, J. D. & Han, K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Development of materials related to the 60T and 100T magnets

In the past year, the effort in materials science related to the 60T and 100T magnets at Los Alamos has been concentrated in three areas: (a) development of a fabrication route for Cu-Ag wire in collaboration with Handy and Harman and IGC and (b) investigation of the mechanical properties of a variety of potential high strength high conductivity materials (c) selection of the reinforcement materials for the coils and development of a fabrication route for these materials. The selection of the c… more

Date: December 31, 1997

Creator: Han, K. & Embury, J. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Survey of Processing Methods for High Strength High Conductivity Wires for High Field Magnet Applications

This paper will deal with the basic concepts of attaining combination of high strength and high conductivity in pure materials, in-situ composites and macrocomposites. It will survey current attainments, and outline where some future developments may lie in developing wire products that are close to the theoretical strength of future magnet applications.

Date: October 1, 1998

Creator: Han, K. & Embury, J. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Strain hardening at large strains

The strain hardening properties of various fcc metals have been investigated at large strains by means of torsion tests of short thin-walled cylinders. The results show that Stage IV occurs in all cases provided that a low enough test temperature is used; it is a nearly constant hardening rate of 2.10/sup /minus/4/ G in terms of resolved flow stress. Stage IV strain hardening has been modeled by considering the effects of accumulation of dislocation debris, such as dipoles and loops, in the ''s… more

Date: January 1, 1988

Creator: Rollett, A. D.; Kocks, U. F.; Embury, J. D.; Stout, M. G. & Doherty, R. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Deformation texture development in a model composite system

Model composites fabricated with a polycrystalline copper matrix and continuous tungsten fibres were deformed in plane strain compression with the fibres perpendicular to the loading axis and parallel to the direction of zero strain. The development of texture in the matrix due to deformation was measured using x-ray diffraction. It was observed that the macroscopic texture development in the composite was weaker than for unreinforced copper. The pattern of deformation in the matrix was quantif… more

Date: May 1, 1995

Creator: Poole, W. J.; MacEwen, S.; Kocks, U. F. & Embury, J. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Light weight cellular structures based on aluminium

An interesting form of lightweight material which has emerged in the past 2 decades is metallic foam. This paper deals with the basic concepts of making metallic foams and a detailed study of foams produced from Al-SiC. In addition, some aspects of cellular solids based on honeycomb structures are outlined including the concept of producing both two-phase foams and foams with composite walls.

Date: February 1, 1997

Creator: Prakash, O.; Embury, J. D.; Sinclair, C.; Sang, H. & Silvetti, P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

On recrystallization in metal matrix composites

The plane strain deformation of model continuous fibre composites such as Cu-W provides a vehicle for the study of the macroscopic effects of second phase particles on the strain distribution in the matrix and its possible effects on subsequent recrystallization behaviour. By using metallographic studies based both on optical gridding methods and low temperature recrystallization, the pattern of flow enforced by the fibres can be quantified and related to the spatial distribution of recrystalli… more

Date: May 1, 1992

Creator: Poole, W. J.; Embury, J. D.; Silvetti, S. P. & Kocks, U. F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The structure and mechanical properties of Ru-Cu and Ru-Ti nanolayer composites

Multilayers of Ru-Cu and Ru-Ti have been prepared by electron beam evaporation technique. One set of composites has Ru thickness varying from 250 to 2500{Angstrom} alternating with Cu or Ti of 15{Angstrom}. The other set has 250{Angstrom} of Ru and the Cu or Ti layer varies between 15 and 200{Angstrom}. Nanoindentation measurements show that there is no significant change in hardness as either Ru or Cu/Ti thickness varies. However, the Ru-Cu multilayer has twice the hardness of the Ru-Ti system… more

Date: June 1, 1993

Creator: Kung, H.; Nastasi, M.; Jervis, T. R.; Hubbard, K.; Mitchell, T. E.; Messner, R. M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Advanced deformation process modeling

Progress was made in achieving a comprehensive and coherent description of material behavior in deformation processing. The materials included were metals, alloys, intermetallic compounds, arbitrary lattice structure, and metal matrix composites. Aspects of behavior modeled included kinetics of flow and strain hardening, as well as recrystallization and the various anisotropies of strength and compliance. Highlights include a new prediction of the limiting strength of materials at high temperat… more

Date: August 1, 1997

Creator: Kocks, U. F.; Embury, J. D.; Beaudoin, A. J.; Dawson, P. R.; MacEwen, S. R. & Mecking, H. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Plastic behavior of Cu/Ni multilayers

In order to study the plasticity in Cu-Ni multilayers deposited on single crystals of nanoindentation measurements, and by the transmission of well characterized dislocations from the underlying substrate by tensile deformation of Cu single crystals. Various multilayers were deposited by physical vapor deposition with layer thicknesses varying between 1,000 and 20 Angstroms (for a total thickness between 0.8 and 1 {micro}m). Two types of experiments were designed. The first one aimed at injecti… more

Date: December 31, 1998

Creator: Verdier, M.; Hawley, M.; Nastasi, M.; Kung, H.; Niewczas, M. & Embury, J. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Fabrication Routes for High Strength High Conductivity Wires

The development of suitable wires for magnet windings requires both the attainment of suitable combinations of properties (electrical conductivity and strength), the development of a production route capable of fabricating suitable quantity of wire of required dimension (5.2x7.6mm{sup 2} cross-section and 120 m in length) and a product with acceptable fabricability, joinability and service life. In this survey, the authors consider methods of producing suitable wire products by the codeformatio… more

Date: October 1, 1998

Creator: Han, K.; Embury, J. D.; Sims, J. R.; Pantsyrnyi, V. I.; Shikov, A. & Bochvar, A. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Microstructure of depleted uranium under uniaxial strain conditions

Uranium samples of two different purities were used for spall strength measurements. Samples of depleted uranium were taken from very high purity material (38 ppM carbon) and from material containing 280 ppM C. Experimental conditions were chosen to effectively arrest the microstructural damage at two places in the development to full spall separation. Samples were soft recovered and characterized with respect to the microstructure and the form of damage. This allowed determination of the depen… more

Date: September 1997

Creator: Zurek, A. K.; Embury, J. D.; Kelly, A.; Thissell, W. R.; Gustavsen, R. L.; Vorthman, J. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Attempts to model the generation of new grain boundaries during the deformation of polycrystals

We explore ways by which new orientations (``nuclei``) can arise during essentially homogeneous deformation in polycrystals. All of these can be categorized as generating new large-angle boundaries: one is due to excessive storage of dislocations of one sign parallel to existing grain boundaries; another is due to reactions of cell walls with grain edges; and in the last, new boundaries are created surrounding a domain of different slip system distribution.

Date: December 31, 1993

Creator: Kocks, U. F.; Cotton, J. D.; Chen, S. R.; Wright, S. I.; Rollett, A. D.; Embury, J. D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Internal Stresses in Wires for High Field Magnets

The codeformation of Cu-Ag or Cu-Nb composite wires used for high field magnets has a number of important microstructural consequences, including the production of very fine scale structures, the development of very high internal surface area to volume ratios during the drawing and the storage of defects at interphase interfaces. In addition, the fabrication and codeformation of phases which differ in crystal structure, thermal expansion, elastic modulus and lattice parameter lead to the develo… more

Date: October 1, 1998

Creator: Han, K.; Embury, J. D.; Lawson, A. C.; Von Dreele, R. B.; Wood, J. T. & Richardson Jr., J. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Residual stress, mechanical behavior and electrical properties of Cu/Nb thin-film multilayers

Effect of compositional wavelength (modulation) on residual stress, electrical resistivities and mechanical properties of Cu/Nb thin-film multilayers sputtered onto single-crystal Si substrates, was evaluated. Electrical resistivities were measured down to 4 K using a standard 4-point probe. Differential specimen curvature was used to determine residual stress, and a microprobe was used to obtain hardness and elastic modulus. Profilometry, ion-beam analysis and TEM were used. Hardness of the Cu… more

Date: September 1995

Creator: Griffin, A. J., Jr.; Hundley, M. F.; Jervis, T. R.; Kung, H. H.; Scarborough, W. K.; Walter, K. C. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

On recrystallization in metal matrix composites

Date: January 1, 1992

Creator: Poole, W.J.; Embury, J.D. (McMaster Univ., Hamilton, ON (Canada)); Silvetti, S.P. (Cordoba Univ. Nacional (Argentina)) & Kocks, U.F. (Los Alamos National Lab., NM (United States))

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Texture development in CU-W composites

A model system of polycrystalline Cu containing continuous fibres of W has been deformed in plane strain compression so that the imposed flow occurred perpendicular to the fibre axis. A technique has been developed to grid the sample to examine the detailed distribution of strain around the fibres. In addition, texture measurements have been conducted to compare the behaviour of the composite with that of unreinforced copper of similar grain size. These observations allow the texture components… more

Date: January 1, 1991

Creator: Poole, W.J.; Embury, J.D. (McMaster Univ., Hamilton, ON (Canada)); Kocks, U.F. (Los Alamos National Lab., NM (USA)) & Bolmaro, R.E. (Rosario Univ. Nacional (Argentina))

Item Type: Article

Partner: UNT Libraries Government Documents Department