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2099 full-text articles. Page 1 of 32.

Fabrication And Study Of The Structure And Magnetism Of Rare-Earth Free Nanoclusters, Bhaskar Das 2017 University of Nebraska-Lincoln

Fabrication And Study Of The Structure And Magnetism Of Rare-Earth Free Nanoclusters, Bhaskar Das

Theses, Dissertations, and Student Research: Department of Physics and Astronomy

No abstract provided.


Half-Metallic Co-Based Quaternary Heusler Alloys For Spintronics: Defect- And Pressure-Induced Transitions And Properties, Enamullah, D. D. Johnson, K. G. Suresh, Aftab Alam 2017 Indian Institute of Technology Bombay

Half-Metallic Co-Based Quaternary Heusler Alloys For Spintronics: Defect- And Pressure-Induced Transitions And Properties, Enamullah, D. D. Johnson, K. G. Suresh, Aftab Alam

Duane D. Johnson

Heusler compounds offer potential as spintronic devices due to their spin polarization and half-metallicity properties, where electron spin-majority (minority) manifold exhibits states (band gap) at the electronic chemical potential, yielding full spin polarization in a single manifold. Yet, Heuslers often exhibit intrinsic disorder that degrades its half-metallicity and spin polarization. Using density-functional theory, we analyze the electronic and magnetic properties of equiatomic Heusler (L21) CoMnCrAl and CoFeCrGe alloys for effects of hydrostatic pressure and intrinsic disorder (thermal antisites, binary swaps, and vacancies). Under pressure, CoMnCrAl undergoes a metallic transition, while half-metallicity in CoFeCrGe is retained for a limited range. Antisite ...


Origin Of Magnetic Anisotropy In Doped Ce2co17 Alloys, Liqin Ke, D. A. Kukusta, Duane D. Johnson 2017 Ames Laboratory

Origin Of Magnetic Anisotropy In Doped Ce2co17 Alloys, Liqin Ke, D. A. Kukusta, Duane D. Johnson

Duane D. Johnson

Magnetocrystalline anisotropy (MCA) in doped Ce2Co17 and other competing structures was investigated using density functional theory. We confirmed that the MCA contribution from dumbbell Co sites is very negative. Replacing Co dumbbell atoms with a pair of Fe or Mn atoms greatly enhance the uniaxial anisotropy, which agrees quantitatively with experiment, and this enhancement arises from electronic-structure features near the Fermi level, mostly associated with dumbbell sites. With Co dumbbell atoms replaced by other elements, the variation of anisotropy is generally a collective effect and contributions from other sublattices may change significantly. Moreover, we found that Zr doping promotes the ...


Large Energy Product Enhancement In Perpendicularly Coupled Mnbi/Cofe Magnetic Bilayers, T. R. Gao, L. Fang, S. Fackler, S. Maruyama, X. H. Zhang, L. L. Wang, T. Rana, P. Manchanda, A. Kashyap, K. Janicka, A. L. Wysocki, A. T. N'Diaye, E. Arenholz, J. A. Borchers, B. J. Kirby, B. B. Maranville, K. W. Sun, M. J. Kramer, V. P. Antropov, D. D. Johnson, R. Skomski, J. Cui, I. Takeuchi 2017 University of Maryland at College Park

Large Energy Product Enhancement In Perpendicularly Coupled Mnbi/Cofe Magnetic Bilayers, T. R. Gao, L. Fang, S. Fackler, S. Maruyama, X. H. Zhang, L. L. Wang, T. Rana, P. Manchanda, A. Kashyap, K. Janicka, A. L. Wysocki, A. T. N'Diaye, E. Arenholz, J. A. Borchers, B. J. Kirby, B. B. Maranville, K. W. Sun, M. J. Kramer, V. P. Antropov, D. D. Johnson, R. Skomski, J. Cui, I. Takeuchi

Duane D. Johnson

We demonstrate substantial enhancement in the energy product of MnBi-based magnets by forming robust ferromagnetic exchange coupling between a MnBi layer and a thin CoFe layer in a unique perpendicular coupling configuration, which provides increased resistance to magnetization reversal. The measured nominal energy product of 172kJ/m3 at room temperature is the largest value experimentally attained for permanent magnets free of expensive raw materials. Our finding shows that exchange-coupled MnBi/CoFe magnets are a viable option for pursuing rare-earth-free magnets with energy products approaching those containing rare-earth elements.


Intrinsic Magnetic Properties In R(Fe1−Xcox)11tiz(R=Yand Ce;Z=H,C,And N), Liqin Ke, Duane D. Johnson 2017 Ames Laboratory

Intrinsic Magnetic Properties In R(Fe1−Xcox)11tiz(R=Yand Ce;Z=H,C,And N), Liqin Ke, Duane D. Johnson

Duane D. Johnson

To guide improved properties coincident with reduction of critical materials in permanent magnets, we investigate via density functional theory (DFT) the intrinsic magnetic properties of a promising system, R(Fe1−xCox)11TiZ with R=Y, Ce and interstitial doping (Z=H,C,N). The magnetization M, Curie temperature TC, and magnetocrystalline anisotropy energy K calculated in local density approximation to DFT agree well with measurements. Site-resolved contributions to K reveal that all three Fe sublattices promote uniaxial anisotropy in YFe11Ti, while competing anisotropy contributions exist in YCo11Ti. As observed in experiments on R(Fe1−xCox)11Ti, we find a complex ...


A Ship-In-A-Bottle Strategy To Synthesize Encapsulated Intermetallic Nanoparticle Catalysts: Exemplified For Furfural Hydrogenation, Raghu V. Maligal-Ganesh, Chaoxian Xiao, Tian Wei Goh, Lin-Lin Wang, Jeffrey Gustafson, Yuchen Pei, Zhiyuan Qi, Duane D. Johnson, Shiran Zhang, Franklin Feng Tao, Wenyu Huang 2017 Iowa State University

A Ship-In-A-Bottle Strategy To Synthesize Encapsulated Intermetallic Nanoparticle Catalysts: Exemplified For Furfural Hydrogenation, Raghu V. Maligal-Ganesh, Chaoxian Xiao, Tian Wei Goh, Lin-Lin Wang, Jeffrey Gustafson, Yuchen Pei, Zhiyuan Qi, Duane D. Johnson, Shiran Zhang, Franklin Feng Tao, Wenyu Huang

Duane D. Johnson

Intermetallic compounds are garnering increasing attention as efficient catalysts for improved selectivity in chemical processes. Here, using a ship-in-a-bottle strategy, we synthesize single-phase platinum-based intermetallic nanoparticles (NPs) protected by a mesoporous silica (mSiO2) shell by heterogeneous reduction and nucleation of Sn, Pb, or Zn in mSiO2-encapsulated Pt NPs. For selective hydrogenation of furfural to furfuryl alcohol, a dramatic increase in activity and selectivity is observed when intermetallic NPs catalysts are used in comparison to Pt@mSiO2. Among the intermetallic NPs, PtSn@mSiO2 exhibits the best performance, requiring only one-tenth of the quantity of Pt used ...


Cermet Development For High Temperature And High Pressure Applications, Beatriz Justus Ferez, Samantha Guthrie, Brian J. Jaques (Mentor), Darryl P. Butt (Mentor) 2017 Boise State University

Cermet Development For High Temperature And High Pressure Applications, Beatriz Justus Ferez, Samantha Guthrie, Brian J. Jaques (Mentor), Darryl P. Butt (Mentor)

Idaho Conference on Undergraduate Research

Many traditionally used low cost alloys are easily corroded in steam or supercritical CO2. An effective solution is to utilize ceramic heat exchangers that are often integrated with metallic components which result in a significant thermal expansion mismatch. The goal of this project is to develop a sealing method to create a hermetic joint between the ceramic and metal alloy. Proposed is a seal ring containing a cermet powder with a coefficient of thermal expansion (CTE) higher than the ceramic and metal to produce a high temperature compressive seal. Cermets of Ag and MgO have been selected to withstand ...


Microstructure Control And Correlation To Creep Properties In Grade 91 Steel Weldment After Thermo-Mechanical Treatments And An Fe-30cr-3al Alloy Strengthened By Fe2nb Laves Phase, Benjamin Allen Shassere 2016 University of Tennessee, Knoxville

Microstructure Control And Correlation To Creep Properties In Grade 91 Steel Weldment After Thermo-Mechanical Treatments And An Fe-30cr-3al Alloy Strengthened By Fe2nb Laves Phase, Benjamin Allen Shassere

Doctoral Dissertations

Type IV cracking in weldments of steel pipes after creep deformation is a concern in modern fossil-fueled power plants. Two possible methods for minimizing or eliminating Type IV cracking will be discussed. The first method alters the initial microstructure of typical Grade 91 steel base metal before welding, while the second provides baseline microstructure characteristics and creep performance of a new alloy that is strengthened by the intermetallic Fe2Nb Laves phase. The initial microstructure of the Grade 91 steel can be controlled by Thermo-Mechanical Treatments, which aids in precipitation of fine (5-10 nm) MX particles in austenite before transformation to ...


Half-Metallic Co-Based Quaternary Heusler Alloys For Spintronics: Defect- And Pressure-Induced Transitions And Properties, Enamullah, D. D. Johnson, K. G. Suresh, Aftab Alam 2016 Indian Institute of Technology Bombay

Half-Metallic Co-Based Quaternary Heusler Alloys For Spintronics: Defect- And Pressure-Induced Transitions And Properties, Enamullah, D. D. Johnson, K. G. Suresh, Aftab Alam

Ames Laboratory Publications

Heusler compounds offer potential as spintronic devices due to their spin polarization and half-metallicity properties, where electron spin-majority (minority) manifold exhibits states (band gap) at the electronic chemical potential, yielding full spin polarization in a single manifold. Yet, Heuslers often exhibit intrinsic disorder that degrades its half-metallicity and spin polarization. Using density-functional theory, we analyze the electronic and magnetic properties of equiatomic Heusler (L21) CoMnCrAl and CoFeCrGe alloys for effects of hydrostatic pressure and intrinsic disorder (thermal antisites, binary swaps, and vacancies). Under pressure, CoMnCrAl undergoes a metallic transition, while half-metallicity in CoFeCrGe is retained for a limited range. Antisite ...


A356 Aluminum Alloy, Grain Refining, Modification, Microstructure, Mechanical Properties, Jonghun Yoon 2016 Hanyang University

A356 Aluminum Alloy, Grain Refining, Modification, Microstructure, Mechanical Properties, Jonghun Yoon

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Modelling The Evaporation Of Aluminum In Ti–6al–4v Alloy Melted With Electron Beam And Laser, Xuan Wang, Liang Wang, Liang S. Luo, Yan Q. Su, Xin Z. Li, Rui R. Chen, JIng J. Guo, Heng Z. Fu 2016 Harbin Institute of Technology

Modelling The Evaporation Of Aluminum In Ti–6al–4v Alloy Melted With Electron Beam And Laser, Xuan Wang, Liang Wang, Liang S. Luo, Yan Q. Su, Xin Z. Li, Rui R. Chen, Jing J. Guo, Heng Z. Fu

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Study On Criterion Of Fabricating Columnar Dendrite Structure Dz466 Superalloy Based On Lmc Process, Xun Sun 2016 Shenyang Research Institute of Foundry

Study On Criterion Of Fabricating Columnar Dendrite Structure Dz466 Superalloy Based On Lmc Process, Xun Sun

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Experimental Investigation On Recovery Of Fe-Ni Alloy From Bayer Red Mud And Laterite Nickel, Aoping He, Chen Liu, Jianmin Zeng 2016 Guangxi Institute of Metallurgy

Experimental Investigation On Recovery Of Fe-Ni Alloy From Bayer Red Mud And Laterite Nickel, Aoping He, Chen Liu, Jianmin Zeng

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Microstructures And Properties Of Sintered Cu–Mos2/Cu Functional Gradient Materials, Aiqin Wang 2016 Henan University of Science and Technology

Microstructures And Properties Of Sintered Cu–Mos2/Cu Functional Gradient Materials, Aiqin Wang

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


(Alpha + Gamma) Ultrafine Duplex Structure Formation In Twophase Stainless Steel By High-Pressure Torsion And Annealing, Mie Ota, Kei Ameyama, Daiki Nanya, Sanjay Kumar Vajpai 2016 Ritsumeikan University

(Alpha + Gamma) Ultrafine Duplex Structure Formation In Twophase Stainless Steel By High-Pressure Torsion And Annealing, Mie Ota, Kei Ameyama, Daiki Nanya, Sanjay Kumar Vajpai

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Study On The Impact Abrasive Wear Of New Super-High Manganese Steel, Wenyan Wang 2016 Henan University of Science and Technology

Study On The Impact Abrasive Wear Of New Super-High Manganese Steel, Wenyan Wang

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Modelling The Softening Behaviour During Galvanizing Of Various Steel Grades, Kevin Banks, Rorisang Maubane, Thabang Makwena 2016 University of Pretoria

Modelling The Softening Behaviour During Galvanizing Of Various Steel Grades, Kevin Banks, Rorisang Maubane, Thabang Makwena

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Numerical Simulation On The Combustion Characteristic Of Iron Ore Sintering With Flue Gas Recirculation, Gan Wang, Zhi Wen, Guofeng Lou, Ruifeng Dou, Xunliang Liu, Fuyong Su, Sizong Zhang 2016 University of Science and Technology Beijing

Numerical Simulation On The Combustion Characteristic Of Iron Ore Sintering With Flue Gas Recirculation, Gan Wang, Zhi Wen, Guofeng Lou, Ruifeng Dou, Xunliang Liu, Fuyong Su, Sizong Zhang

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


A Parallel 3d Phase-Field Simulation Of Multi-Grain Growth Based On The Full Thread Tree, Ya-jun Yin, Min Wang, Jian-xin Zhou, Dun-ming Liao, Xu Shen, Tao Chen 2016 Huazhong University of Science and Technology

A Parallel 3d Phase-Field Simulation Of Multi-Grain Growth Based On The Full Thread Tree, Ya-Jun Yin, Min Wang, Jian-Xin Zhou, Dun-Ming Liao, Xu Shen, Tao Chen

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Effect Of Er On Microstructure And Electrochemical Performance Of Al–Zn–In Anode, Zhengbing Xu 2016 Guangxi University

Effect Of Er On Microstructure And Electrochemical Performance Of Al–Zn–In Anode, Zhengbing Xu

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


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