Download or read book Development of a Numerical Model on Radiation Induced Segregation and Surface Nano Structuring in a Binary System written by and published by . This book was released on 2014 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2540 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Radiation Tolerant Interface Design and Complexion Dynamics Via Atomistic Modeling written by Joseph Earl Ludy and published by . This book was released on 2016 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Traditionally, grain boundary character in nanoscale materials has been tailored to maximize different types of mechanical behavior, whether it be exhibiting near-theoretical strengths or prolonging fracture by dramatically increasing a material's ductility. As more complex systems develop for nuclear and other extreme environment applications, the need for these types of materials is quickly identified. Specifically, materials in a nuclear reactor need to be amended to extend their longevity to promote safety and reliable usage. One strategy for improving radiation tolerance is the design and control of internal interfaces in a material. Atomistic simulations can give insight into the foundational principles of grain boundary structure and formation.Two comprehensive simulation models are developed to bridge this gap with respect to radiation tolerant interfaces and structural transitions in binary alloy systems. Firstly, the radiation damage of an ordered grain boundary is compared to a disordered amorphous intergranular film, to investigate how interface thickness and free volume impacts point defect recombination. Collision cascades are simulated and residual point defect populations are analyzed as a function of boundary type and primary knock on atom energy. Secondly, hybrid Monte Carlo/molecular dynamics simulations are used to study segregation-induced intergranular film formation in Cu-Zr and Cu-Nb alloys. While Cu-Zr alloys form structurally disordered or amorphous films, second phases precipitate at the interfaces of Cu-Nb. Finally, the effect of free surfaces on dopant segregation and complexion formation is investigated for both alloys.
Download or read book Nanostructure Design by Atomic Shadowing written by Chunming Zhou and published by ProQuest. This book was released on 2015 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research work is to develop an understanding of the atomic process, especially the roles of surface diffusion and surface pattern, that govern the formation of nanostructures by the current state-of-the-art glancing angle deposition (GLAD) technique and to explore the possibility of extending the capabilities of GLAD to S̲imultaneous O̲pposite G̲lancing A̲ngle D̲eposition (SOGLAD) for multi-component nanostructuring. The effects of surface diffusion during GLAD were investigated by growing periodic Ta nanopillar arrays on patterned substrates at temperatures T [subscript] s ranging form 200 to 900°C. For growth at high T [subscript] s, the structure and morphology of Ta nanopillars is strongly affected by the increased surface diffusion. Branching of pillar tops occurs for growth at low T [subscript] s, while sub-pillars form during the nucleation stage at the pillar bottoms at high T [subscript] s. The formation of sub-pillars at the bottom is attributed to a transition to a multi-pillar nucleation mode at high T [subscript] s. There is also a transition to a competitive columnar growth mode at elevated temperatures, caused by an increased adatom diffusion length. The competitive growth mode results in an increase in the average pillar width, a decrease in the pillar separation and pillar number density, the accelerated growth of some pillars at the cost of others which die out, and an increased probability for the merging of neighboring pillars. The top branching is associated with kinetic roughening and limited adatom mobility at low T [subscript] s. The fraction of branched pillars decreases with increasing T [subscript] s, due to an increased lateral diffusion length, and is described with a simple nucleation model, providing an effective activation energy for Ta surface diffusion of 2.0 eV. The surface patterning effects were studied by growing nanostructured layers onto two types of regular surface patterns: honeycomb nanodot arrays and pyramidal pit arrays, created by Nanosphere Lithography (NSL). GLAD on NSL nanodot patterns results in honeycomb nanopillar arrays while GLAD on inverted pyramid pit patterns leads to two level porous layers with microscopic pores (> 300 nm) interconnected by nanoscale (5-50 nm) pores. Statistical size analyses from honeycomb nanopillar arrays show that the distribution in w broadens with increasing l and decreasing w , but remains approximately constant with a fixed l/w -ratio. This is attributed to an intercolumnar growth competition that exacerbates nanorod size fluctuations but scales with rod size, indicating that the overall nanostructure-shape during low-temperature GLAD is independent of material-specific length-scales and, therefore, completely controlled by the geometric shadowing. Microstructural evolution of two level porous Ta and Al GLAD layers is dominated by long-range atomic shadowing interactions that lead to the formation of separated vertical rods and the development of a bimodal pore structure. The nanorods grow in a competitive mode which causes rod broadening and rod extinction. Both the broadening and extinction of the rods can be quantified by a power law. The large surface diffusion length for Al rods causes a lateral growth which enhances the rod broadening and, in turn, leads to the close-up of the microscopic pores, indicating that Al layers grown on pit arrays approach a microstrostructure that is comparable to GLAD layers grown on flat substrates. In contrast, the bimodal pore structure is well preserved during Ta growth, which indicates that substrate patterning is a useful approach to create complex pore arrangements in GLAD layers for growth conditions where surface diffusion is negligible. GLAD has also been extended to SOGLAD to fabricate novel Si/Ta two component nanostructures onto self-assembled close-packed silica nanosphere arrays. The two component nanostructures are shaped into zigzags or nanopillars by adjusting the deposition angle and/or the substrate rotation. By manipulating the sequence of the deposition, that is, by sequential or simultaneous deposition from two sources, complex nanostructures are formed where the two components are stacked vertically, laterally, or in a checker board arrangement. Scanning electron microscopy, back scattered imaging, and transmission electron microscopy provide clear compositional and microstructural contrast and show sharp (
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1967 with total page 978 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Binary Nano structuring written by Liaoyong Wen and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanostrukturarrays, bestehend aus den zwei Unterteilungen "Nanostruktur" und "Array", sind elementar für viele moderne und zukünftige technologische Anwendungen oder Systeme. Binäre Nanostrukturarrays, in denen beide, die "Nanostruktur" und die "Array", unabhängig voneinander eingestellt und genutzt werden können, könnten einen neuen Horizont durch Interaktionen zwischen den Sub-Arrays, welche unter Einfach-Arrays unzugänglich sind, eröffnen. Eine allgemeine Methode wird entwickelt um verschiedene Nanostrukturarrays (z.B. Nanowire/Nanowire, Nanotube/Nanowire, Nanotube/Nanotube, Nanodot/Nanodot) mit struktureller Flexibilität und hoher Steuerbarkeit für jedes der Sub-Arrays individuell herzustellen. Der Schlüssel zu dieser Methode basiert auf den charakteristischen binären Poren von anodischen Aluminium Templaten, welche beidseitig entgegengesetzte Barriere-Oxid-Schichten besitzen. Mittels desselben Mechanismus kann das Templat zu einem Viel-Array-Templat (z.B. dreifach oder vierfach) in einer Matrix mit noch höheren Porendichten und weiteren morphologischen Möglichkeiten erweitert werden. Die Vielseitigkeit der binären Nanostrukturierung wird untersucht für die Realisierung innovativer Anwendungen, wie zum Beispiel makroskopische Titandioxid/Kupfer(I)-oxid Z-Schema Photosyntheseeinheiten und nanoskopisch große adressierbare Zinkoxid/Aluminiumzinkoxid vertikale Nanodraht-Transistoren. Des Weiteren wird Nanoengineering von Einfacharrays durchgeführt, dazu werden leistungsstarke Superkondensatoren basierend auf Platin/Manganoxid-Core/Shell-Nanotubearrays und photoelektrochemische Zellen basierend auf Nano-Gold/Pb(Zr,Ti)O3 Hybriden nachgegangen durch welche die optimale Struktur und Zusammensetzung der Einfacharrays wichtige Informationen für multifunktionale Anwendungen basierend auf binären Nanostrukturarrays liefern.
Download or read book Efficient Modeling and Optimization of Surface Second harmonic Generation from written by Anton Pakhomov and published by . This book was released on 2021* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The thesis addresses the development of efficient numerical techniques for the simulation of the surface SHG phenomena from nanostructures and metasurfaces. Chapter 2 is dedicated to the development of a numerical approach based on the transfer matrix method for modeling of surface SHG from multilayer structures. The performance of the developed transfer matrix method is tested for several exemplary stacks. Chapter 3 is devoted to the development of a fully finite-element numerical method for efficient modeling of surface SHG effects. This method treats the surface nonlinear polarization as the deltasurface source embedded into the respective interfaces between two media. It is shown that the proposed method allows modeling of surface nonlinear effects from arbitrary-shaped all-dielectric and plasmonic isolated nanoparticles, as well as metasurfaces. Chapter 4 focuses on the numerical investigation of the symmetry properties of the bulk and surface nonlinear tensors in noncentrosymmetric semiconductors, which result in specific signatures in the polarization-resolved far-field SHG pattern. It is demonstrated that under the plane-wave illumination of a slab of a noncentrosymmetric III-V semiconductor the differences arise in the angular dependence of the emitted second-harmonic radiation on the angle of the crystal axis rotation. The results are then extended to the case of an illumination by a linearly polarized tightly-focused Gaussian beam and the specific signatures of surface and bulk nonlinearities are also obtained in the polarization-resolved far-field SHG patterns. Finally, Chapter 5 is devoted to the numerical studies of the surface SHG from multilayer structures of different possible compositions. Using the developed transfer matrix method the optimal geometry of the multilayer structures is sought for the efficient surface-driven SHG. The achievable SHG conversion efficiency is analysed both in nonperiodic and periodic multilayer structures.
Download or read book Characterisation of Radiation Damage by Transmission Electron Microscopy written by M.L Jenkins and published by CRC Press. This book was released on 2000-11-21 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: Characterization of Radiation Damage by Transmission Electron Microscopy details the electron microscopy methods used to investigate complex and fine-scale microstructures, such as those produced by fast-particle irradiation of metals or ion implantation of semiconductors. The book focuses on the methods used to characterize small point-defect clusters, such as dislocation loops, because the coverage in general microscopy textbooks is limited and omits many of the problems associated with the analysis of these defects. The book also describes in situ, high-resolution, and analytical techniques. Techniques are illustrated with examples, providing a solid overview of the contribution of TEM to radiation damage mechanisms. The book is most useful to researchers in, or entering into, the field of defect analysis in materials.
Download or read book Physics Briefs written by and published by . This book was released on 1993 with total page 1058 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metals Abstracts written by and published by . This book was released on 1998-04 with total page 1176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 694 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fundamentals of Radiation Materials Science written by GARY S. WAS and published by Springer. This book was released on 2016-07-08 with total page 1014 pages. Available in PDF, EPUB and Kindle. Book excerpt: The revised second edition of this established text offers readers a significantly expanded introduction to the effects of radiation on metals and alloys. It describes the various processes that occur when energetic particles strike a solid, inducing changes to the physical and mechanical properties of the material. Specifically it covers particle interaction with the metals and alloys used in nuclear reactor cores and hence subject to intense radiation fields. It describes the basics of particle-atom interaction for a range of particle types, the amount and spatial extent of the resulting radiation damage, the physical effects of irradiation and the changes in mechanical behavior of irradiated metals and alloys. Updated throughout, some major enhancements for the new edition include improved treatment of low- and intermediate-energy elastic collisions and stopping power, expanded sections on molecular dynamics and kinetic Monte Carlo methodologies describing collision cascade evolution, new treatment of the multi-frequency model of diffusion, numerous examples of RIS in austenitic and ferritic-martensitic alloys, expanded treatment of in-cascade defect clustering, cluster evolution, and cluster mobility, new discussion of void behavior near grain boundaries, a new section on ion beam assisted deposition, and reorganization of hardening, creep and fracture of irradiated materials (Chaps 12-14) to provide a smoother and more integrated transition between the topics. The book also contains two new chapters. Chapter 15 focuses on the fundamentals of corrosion and stress corrosion cracking, covering forms of corrosion, corrosion thermodynamics, corrosion kinetics, polarization theory, passivity, crevice corrosion, and stress corrosion cracking. Chapter 16 extends this treatment and considers the effects of irradiation on corrosion and environmentally assisted corrosion, including the effects of irradiation on water chemistry and the mechanisms of irradiation-induced stress corrosion cracking. The book maintains the previous style, concepts are developed systematically and quantitatively, supported by worked examples, references for further reading and end-of-chapter problem sets. Aimed primarily at students of materials sciences and nuclear engineering, the book will also provide a valuable resource for academic and industrial research professionals. Reviews of the first edition: "...nomenclature, problems and separate bibliography at the end of each chapter allow to the reader to reach a straightforward understanding of the subject, part by part. ... this book is very pleasant to read, well documented and can be seen as a very good introduction to the effects of irradiation on matter, or as a good references compilation for experimented readers." - Pauly Nicolas, Physicalia Magazine, Vol. 30 (1), 2008 “The text provides enough fundamental material to explain the science and theory behind radiation effects in solids, but is also written at a high enough level to be useful for professional scientists. Its organization suits a graduate level materials or nuclear science course... the text was written by a noted expert and active researcher in the field of radiation effects in metals, the selection and organization of the material is excellent... may well become a necessary reference for graduate students and researchers in radiation materials science.” - L.M. Dougherty, 07/11/2008, JOM, the Member Journal of The Minerals, Metals and Materials Society.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1985 with total page 1156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ion Solid Interactions written by Michael Nastasi and published by Cambridge University Press. This book was released on 1996-03-29 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive guide to an important materials science technique for students and researchers.
Download or read book Bulk Metallic Glasses written by C. Suryanarayana and published by CRC Press. This book was released on 2017-11-22 with total page 543 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflecting the fast pace of research in the field, the Second Edition of Bulk Metallic Glasses has been thoroughly updated and remains essential reading on the subject. It incorporates major advances in glass forming ability, corrosion behavior, and mechanical properties. Several of the newly proposed criteria to predict the glass-forming ability of alloys have been discussed. All other areas covered in this book have been updated, with special emphasis on topics where significant advances have occurred. These include processing of hierarchical surface structures and synthesis of nanophase composites using the chemical behavior of bulk metallic glasses and the development of novel bulk metallic glasses with high-strength and high-ductility and superelastic behavior. New topics such as high-entropy bulk metallic glasses, nanoporous alloys, novel nanocrystalline alloys, and soft magnetic glassy alloys with high saturation magnetization have also been discussed. Novel applications, such as metallic glassy screw bolts, surface coatings, hyperthermia glasses, ultra-thin mirrors and pressure sensors, mobile phone casing, and degradable biomedical materials, are described. Authored by the world’s foremost experts on bulk metallic glasses, this new edition endures as an indispensable reference and continues to be a one-stop resource on all aspects of bulk metallic glasses.
Download or read book Grain Boundary Segregation in Metals written by Pavel Lejcek and published by Springer Science & Business Media. This book was released on 2010-07-20 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: Grain boundaries are important structural components of polycrystalline materials used in the vast majority of technical applications. Because grain boundaries form a continuous network throughout such materials, their properties may limit their practical use. One of the serious phenomena which evoke these limitations is the grain boundary segregation of impurities. It results in the loss of grain boundary cohesion and consequently, in brittle fracture of the materials. The current book deals with fundamentals of grain boundary segregation in metallic materials and its relationship to the grain boundary structure, classification and other materials properties.
