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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 12 of 12 for “"Polycrystalline Metals"”.
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A Multiscale Method for Simulating Fracture in Polycrystalline Metals
The emerging field of nanomechanics is providing a new focus in the study of the mechanics of materials, particularly in simulating fundamental atomic mechanisms involved in the initiation and evolution of damage. Simulating fundamental material processes using first principles in physics strongly …
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Multiscale Modeling of Fatigue and Fracture in Polycrystalline Metals, 3D Printed Metals, and Bio-inspired Materials
The goal of this research is developing a computational framework to study mechanical fatigue and fracture at different length scales for a broad range of materials. The developed multiscale framework is utilized to study the details of fracture and fatigue for the rolling contact in rails, …
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Shear deformation of amorphous and nanocrystalline copper microstructures via atomistic simulation
… Hall-Petch behavior, yield and flow stresses in polycrystalline metals increase with a decrease in grain size. As grain size continues to decrease, mechanical strength peaks. As grain size further decreases, mechanical strength begins to decrease. As grain size approaches zero, the total …
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Continuum models of deformation mechanisms in nanocrystalline metals
Nanocrystalline metals are polycrystalline metals with grain sizes in the nanometer range. They have attracted significant interest in recent years due to their unique mechanical and electrical properties. The main objective of this thesis is to develop continuum-scale descriptions of nanoscale …
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A finite element model of grain boundary sliding for nanostructured metals
Nanocrystalline metals, i.e., polycrystalline metals with grain sizes in the nanometer range, have elicited significant interest recently due to their potential for achieving higher material strength in combination with increased formability at lower temperatures and higher strain rates, among …
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Mechanical response of polymer matrix composites using indentation stress-strain protocols
… in a variety of materials including single and polycrystalline metals, natural materials and polymers. The goal of this thesis is to extend these protocols to address the unique challenges presented by their application to polymer matrix composites. For this purpose, two disparate materials …
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High throughput prototyping and multiscale indentation characterization of metallic alloys
… responses at different length scales in polycrystalline metals in the form of indentation stress-strain curves. These responses can then be correlated to local material structure using modern data-driven approaches. In this work, we are seeking two main goals. First, exploring the …
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Physically based multiscale-viscoplastic model for metals and steel alloys: theory and computation
… Achieving such desirable goals for material like metals and steel alloys involves a comprehensive study of their microstructures and experimental observations under different loading conditions. In general, metal structures display a strong rate- and temperature-dependence when deformed …
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Fabrication of metal-oxide thin-films and features on dissimilar materials via ion-assisted codeposition
… that ion beams have been used to sputter deposit metals, pattern polycrystalline metals, controllably oxidize metal surfaces, and induce chemical changes in the surfaces of polymers. Presented here is a single step technique that draws on these, utilizing dual ion beams to deposit, oxidize, and …
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Positron Annihilation Lifetime Spectroscopy Methodology and Application to Perovskite Oxide Materials
… performed on commercially available high purity polycrystalline metal samples to reduce the defect concentration below the approximate 0.1 ppm detection limit of PALS. The study showed that despite the numerous reports in literature it was not possible to reproduce the results with similar …
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Anode Materials for High Power Microwave Devices
… manufacturing technique for treatment of metals for vacuum applications. Commercial applications include but are not limited to: laser surface melting of steel chambers for ultra/extreme high vacuum systems (particle accelerators, etc.), analytical techniques (XPS, SIMS, SEM, FIB, etc.). …