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Materials Science and Engineering

Materials Science and Engineering Faculty Research & Creative Works

Series

2005

Articles 1 - 10 of 10

Full-Text Articles in Engineering

Freeze-Form Extrusion Fabrication Of Ceramics, Tieshu Huang, Michael S. Mason, Greg Hilmas, Ming-Chuan Leu Aug 2005

Freeze-Form Extrusion Fabrication Of Ceramics, Tieshu Huang, Michael S. Mason, Greg Hilmas, Ming-Chuan Leu

Materials Science and Engineering Faculty Research & Creative Works

A novel, environmentally friendly solid freeform fabrication method called Freeze-form Extrusion Fabrication (FEF) has been developed for the fabrication of ceramic-based components. The method is based on deposition of ceramic pastes using water as the media. The ceramic solids loading can be 50 vol. % or higher and initial studies have focused on the use of aluminum oxide (Al2O3). The FEF system components and their interaction are examined, and the main process parameters affecting part geometry defined. 3-D shaped components have been fabricated by extrusion deposition of the ceramic paste in a layer-by-layer fashion. The feasibility …

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Integral Channels In Metal Components And Fabrication Thereof, Rajiv S. Mishra Aug 2005

Integral Channels In Metal Components And Fabrication Thereof, Rajiv S. Mishra

Materials Science and Engineering Faculty Research & Creative Works

An internal channel in a metal body for use in applications where internal fluid flow within a metal body is desired, as in a heat exchanger. The internal channel is formed in the metal body by frictionally stirring with a pin plunged into the metal body, and traversing the metal body with the pin.

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Method And Sealant For Weld Joints, David C. Van Aken, John A. Baumann, Richard J. Lederich, Rajesh Talwar Jun 2005

Method And Sealant For Weld Joints, David C. Van Aken, John A. Baumann, Richard J. Lederich, Rajesh Talwar

Materials Science and Engineering Faculty Research & Creative Works

A sealant for a weld joint and an associated weld joint and method are provided. The sealant includes aluminum and germanium and is characterized by a melting temperature that is lower than the melting temperature of the structural member that is joined. The sealant, which is disposed between faying surfaces of the structural members, can fill the spaces between the structural members to prevent the entry of chemicals, moisture, debris, and other substances, thereby reducing the likelihood of corrosion of the joint or structural members at the interface. Further, the sealant can be diffusion bonded to the faying surfaces, for …

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Effect Of Baceo₃ And Basno₃ Additives On Microstructural Development And Critical Current Density Of Melt Textured Yba₂Cu₃O₇₋ₓ, Oratai Jongprateep, Fatih Dogan, Michael Strasik, Kevin E. Mccrary Jan 2005

Effect Of Baceo₃ And Basno₃ Additives On Microstructural Development And Critical Current Density Of Melt Textured Yba₂Cu₃O₇₋ₓ, Oratai Jongprateep, Fatih Dogan, Michael Strasik, Kevin E. Mccrary

Materials Science and Engineering Faculty Research & Creative Works

Improvement of superconducting properties, such as critical current density Jc and trapped magnetic field, of melt textured YBa2Cu3O7-x (Y123) require introducing of effective pinning sites, e.g., nonsuperconducting inclusions, twin boundaries and other defects. It has been shown that addition of small quantities of BaCeO3 (<0.5 wt%) into Y123 results in an increase of the Jc. However, higher cerium concentrations affect the solidification process and inhibit the growth of melt textured Y123 single crystals. In this study, the effect of BaCeO3 additions on the growth and microstructural development of melt textured Y123 single crystals were investigated. The relationship between the solidification kinetics, microstructural development and superconducting properties of Y123 melt textured single crystals with cerium additives is discussed.

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Efficiency In Steel Melting: Opportunities And Progress, Kent D. Peaslee, Semen Naumovich Lekakh, Von Richards, Jay Triplett Jan 2005

Efficiency In Steel Melting: Opportunities And Progress, Kent D. Peaslee, Semen Naumovich Lekakh, Von Richards, Jay Triplett

Materials Science and Engineering Faculty Research & Creative Works

This paper summarizes the findings from a study of melting efficiency in steel foundries and provides examples of material and energy savings from improvements in technology and melting practices. This study is based on information gathered at 19 Steel Founders Society of America member foundries and includes a combination of historical data and industrial measurements by the research team. Information and data were collected on the type of melting equipment, melting practices, energy use and ladle practices. The data was statistically analyzed using STATGRAPHICS commercial software. A multiple regression analysis allowed evaluation of the influence of the melting furnace (type, …

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Alloy Recovery And Control In Steel Melting, Kent D. Peaslee, Darryl S. Webber, Semen Naumovich Lekakh, Bradley Randall Jan 2005

Alloy Recovery And Control In Steel Melting, Kent D. Peaslee, Darryl S. Webber, Semen Naumovich Lekakh, Bradley Randall

Materials Science and Engineering Faculty Research & Creative Works

Alloy recovery plays an important role in steel melting economics because the cost of alloying additives such as ferroalloys and pure non-ferrous metals is significantly higher than the cost of steel scrap. Recovery of alloying additives also influences the reproducibility of steel properties from heat to heat. This paper reviews alloy recovery and final chemistry distributions at seven steel foundries and preliminary laboratory studies of alloy dissolution in ladles. Melting and alloy practices were observed for several plant trial heats in each of the foundries. Alloying and chemistry data were collected for an additional 20 - 155 heats at each …

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Efficiency In Steel Melting: Ladle Development, Kent D. Peaslee, Semen Naumovich Lekakh, Todd P. Sander, Jeffrey D. Smith Jan 2005

Efficiency In Steel Melting: Ladle Development, Kent D. Peaslee, Semen Naumovich Lekakh, Todd P. Sander, Jeffrey D. Smith

Materials Science and Engineering Faculty Research & Creative Works

Effective ladle design and use is important for steel casting production. In foundry operations, the ladle temperature of the liquid steel is typically 150 to 250°F above the steel's melting point to compensate for the heat losses in small ladles and the associated high cooling rates from the large surface area to volume ratios. Higher superheat is also necessary to provide sufficient steel fluidity to properly fill the mold cavity. In spite of the relatively short time that the steel is in contact with the ladle lining, the huge thermal gradients in the lining drive high values of heat flow …

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Coupled Electrical And Magnetic Properties In (La,Sr)Feo3-Δ, X.-D. Zhou, Qingsheng Cai, Jinbo Yang, M. S. Kim, William B. Yelon, William Joseph James, Y.-W. Shin, B. J. Scarfino, Harlan U. Anderson Jan 2005

Coupled Electrical And Magnetic Properties In (La,Sr)Feo3-Δ, X.-D. Zhou, Qingsheng Cai, Jinbo Yang, M. S. Kim, William B. Yelon, William Joseph James, Y.-W. Shin, B. J. Scarfino, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

This article is aimed at studying the temperature dependence oxygen nonstoichiometry, magnetic moments, Fe3+ fraction, Néel temperature and conductivity of (La,Sr)FeO3-δ. It is found that the magnetic properties in La0.60 Sr0.40 Fe3-δ is determined by Fe3+ and its concentration, and the conductance is resulted from Fe4+ ions, which act as electron holes. Both of magnetic and electrical properties were directly governed by oxygen nonstoichiometry (δ). when δ=0.2, the compound has maximum Fe3+, the saturation magnetic moments and Néel temperature are 3.8 µB and 410 °C, both at the highest level, …

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Elevated Temperature Deformation Behavior Of Nanostructured Al-Ni-Gd-Fe Alloys, X. L. Shi, Rajiv S. Mishra, T. J. Watson Jan 2005

Elevated Temperature Deformation Behavior Of Nanostructured Al-Ni-Gd-Fe Alloys, X. L. Shi, Rajiv S. Mishra, T. J. Watson

Materials Science and Engineering Faculty Research & Creative Works

The elevated temperature deformation behavior of nanostructured Al89Ni3Gd7Fe1 alloy was characterized. Tensile strength was 760 MPa at 373 K. Ductility of the alloy increases with increasing strain rate at 573 K. At high temperatures (623-673 K), the operative deformation mechanism is dislocation-climb controlled.

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Study Of The Electronic Structure Of Cafeo₃, Jinbo Yang, M. S. Kim, Qingsheng Cai, X.-D. Zhou, Harlan U. Anderson, William Joseph James, William B. Yelon Jan 2005

Study Of The Electronic Structure Of Cafeo₃, Jinbo Yang, M. S. Kim, Qingsheng Cai, X.-D. Zhou, Harlan U. Anderson, William Joseph James, William B. Yelon

Materials Science and Engineering Faculty Research & Creative Works

We have studied the charge disproportionation phenomenon in CaFeO3 using the local-spin density approximation with the on-site Coulomb interaction parameter U and exchange parameter J. The calculation reveals that the total number of the 3d electrons is about 5.1 for both Fe(1)(Fe5+) and Fe(2)(Fe3+) atoms, and that there are about 0.25 electron holes in the O-2p band. Therefore, the charge disproportionation can be more accurately described as 2d5L(Fe4+)=d5L2(Fe5+)+d5(Fe3+), where L denotes a hole in the oxygen 2p band, instead of 2d4(Fe4+)=d3(Fe5+)+d5(Fe3+). The hybridization between the Fe-3d and O-2p orbitals is stronger for Fe(1) than for Fe(2) due to the shorter …

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