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Showing 1 to 20 of 20 for “"Cu-Nb"”.
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Atomistic simulation of deformation induced rotation in Cu-Nb composites
Accumulative roll bonding (ARB) of three copper-niobium (Cu-Nb) nano-composite models is simulated using molecular statics techniques to assess the rotational stability of Cu-Nb interfaces at high strains up to 90% thickness reduction. Crystals strain and rotate under compression, and certain Cu-Nb …
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Role of interfaces on severe plastic deformation and He-irradiation tolerance in Cu-Nb nanocomposites
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2016-07-07 without embargo terms
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Microstructural evolution and phase stability of Cu/Nb nanolaminates subjected to severe plastic deformation by high pressure torsion
… cases, in the bulk shape. This dissertation focuses on providing a better understanding of deformation mechanisms imposed via severe shear deformation to Cu-Nb nanolaminates fabricated by accumulative roll bonding. Severe plastic deformation was applied in a controlled way using high pressure …
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Modeling radiation-induced mixing at interfaces between low solubility metals
… between low solubility metals using molecular dynamics (MD) computer simulations. It provides original contributions on the fundamental mechanisms of radiation-induced mixing and morphological stability of multilayer nanocomposites under heavy ion or neutron radiation. An embedded atom …
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Atomistic simulations of radiation damage in amorphous metal alloys
… response of amorphous metal alloys. Using a molecular dynamics simulation of /2 MeV ion irradiation in a realistic 2 billion-atom molecular dynamics simulation in amorphous Cu₅₀Nb₅₀, I show that radiation creates isolated nanometer-scale zones with rapidly quenching liquids. Quenched liquids …
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Measuring elastic constants of laminated Copper/Niobium composites using resonant ultrasound spectroscopy
Layered copper/niobium (Cu/Nb) composites with small layer widths contain a high area per unit volume of solid-state interfaces. Interfaces have their own elasticity tensor, which affects the elastic properties of the composite as a whole. We have studied the elastic constants of Cu/Nb composites …
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Irradiation-induced nanoclusters and their evolution in compound forming ni-base and cu-base alloys
… studied in three systems: Ni-W binary, Cu-Mo-Si, Cu-Nb-Si ternary. 1) In the Ni-W system, which forms compounds at low temperature but undergoes phase separation at high temperature, pre-irradiation at RT and post-annealing at 850 °C induced finely dispersed nanoprecipitation with a high …
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Helium behavior at fcc-bcc semicoherent interfaces: trapping, clustering, nucleation, and growth of cavities
… of clusters at fcc-bcc interfaces. Choosing Cu-Nb as a model fcc-bcc interface, a predictive Cu-Nb-He interatomic potential is constructed using density functional theory. These calculations show that two-body radial forces are sucient to describe interactions of He with fcc Cu and bcc Nb. …
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Amorphization and De-vitrification in Immiscible Copper-Niobium Alloy Thin Films
… within the amorphous phase forming in immiscible Cu-Nb alloy thin films using 3D atom probe tomography has been presented. This evidence clearly indicates that the nanoscale phase separation is responsible for the stabilization of the amorphous phase in such immiscible systems since it …
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Development of novel redox stable anode materials and their suitability for use in intermediate temperature solid oxide fuel cells
… conductivity and stability for SrFe₀.₉(Ti,Nb)₀.₁O₃₋δ. Introduction of transition metal dopants further increased the electronic conductivity with copper doping exhibiting the highest electronic conductivity of the redox stable SrFe₃₋₀₉ ̣₁₈₆₄₂₇⁻²°₀.₈-x(TM)x(Ti,Nb)₀.₁O₃-δ materials. …
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Electrodeposition of Nb, Ta, Zr and Cu from Ionic Liquid for Nanocomposites Preparation
… power reactor. Immiscible systems constituted by Cu/Nb or Cu/Ta multilayers exhibit higher thermal stability and improved mechanical properties with respect to bulk Nb, bulk Ta and bulk Cu. Refractory metals present high melting point, high hardness and high resistance against strong acids and …
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Investigating the sink efficiencies of interfaces under irradiation
… concentration profile in the vicinity of a Cu-Nb interface and explains how to extract the sink efficiency by comparing with a chemical rate equation. Chapter 4 is a systematic study for investigating the sink efficiency of different planar interfaces varying from semi/coherent to incoherent …
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Deformation Mechanisms at Grain Boundaries in Polycrystal Plasticity
… applied to predict the unique rolling texture of Cu/Nb nanostructured multilayers occurs due to the confined layer slip of single Orowan loops. The model regards each grain as a composite composed of Cu and Nb crystals. A hardening effect is introduced to account for the interaction between glide …
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Self-Organization of Dilute Copper Binary Alloys Under Ion Irradiations
… irradiation have on model alloy systems, dilute Cu-Ag, Cu-Nb, Cu-Mo and Cu-Fe alloys, and compares their behaviors with existing models on driven systems. For the first three alloys, the microstructure is characterized using X-ray diffraction, transmission electron microscopy and Rutherford …
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Atomistic simulations of deformation in Metallic Nanolayered Composites
… (layer thickness, h) on mechanical response of Cu/Nb MNCs are examined by Molecular Dynamics (MD) simulations. The study of the strength of MNCs show that small changes in both d and h play a profound role in the relative plastic contributions from grain boundary sliding and dislocation glide. …
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Focused Ion Beam Fabricated Non-equilibrium Superconducting Devices
The developments over the last decade in Focused Ion Beam (FIB) instrument technology have reached a point where there is sufficient control of an ion beam to make cuts, trenches, and other shapes in a sample on a scale of tens of nanometers. This work concentrates on the use of an FIB instrument …
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Severe plastic deformation in highly immiscible copper alloys: self-organization
… torsion (HPT), high energy ball milling (BM), accumulative roll bonding (ARB), are well known to refine the microstructures of metals and alloys into non-equilibrium states with nanometer-size grains, and they are gaining widespread interest for processing bulk nanostructured materials. Existing …
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Nanoscale self-organization in irradiated ternary alloys
… several pathways to stabilize nanostructures in Cu-based ternary alloy systems, which contain a very small fraction of refractory alloying element (W) that is highly immiscible with Cu. Three systems with distinct interaction energies have been investigated. 1) In the Cu-Nb-W system, where Nb is …
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Tailoring Li₄Ti₅O₁₂ Thin Film Carrier Kinetics Through Solid Solution Doping for Battery and Memristor Applications
… film, its applications expand to integrated circuits, sensors, flexible batteries, IoT devices, and memristors. Across these, precise control of mixed Li⁺ ionic–electronic transport is vital. While dopants have been shown to improve electron conduction and Li⁺ diffusion in LTO4 powders, …
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Accounting for temperature and local structure in atomistic calculations of interface free energies in metals
… phases such as liquids. I present methods for calculating location-dependent energies for solid-state interfaces and temperature-dependent free energies for solid/liquid interfaces using atomistic models. I demonstrate these methods on CuNbHe and AlGa models due to the importance of location- and …