Download or read book Atomistic Simulations Based Study of Nanoscale Deformation in Copper written by Ajith K. Ukwattage and published by . This book was released on 2014 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigating the Mechanics and Deformation in Multi layered Copper and Niobium Nanowires Using Atomistic Simulations written by Dana Jaclynn Bronen and published by . This book was released on 2016 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis employed atomistic simulations to investigate the role of layer thickness in multi-layered metallic nanowires. Nanowires are of great interest due to their unique mechanical properties and deformation mechanisms. The mechanisms controlling nanowire deformation are highly dependent on the volume fraction and interface orientation between materials within these structures. The behavior all of these variables have on nanowires still widely unknown. Experimental research has not been investigated greatly because of the difficulty, expense and time consuming nature of the fabrication and testing processes. It has been shown that atomistic simulations can probe these fundamental questions while providing vital insight on deformation mechanisms. Therefore, the work performed will exploit atomistic simulations to investigate the deformation mechanisms associated with multi-layered copper and niobium metallic nanowires. An embedded atom method potential was used during molecular statics to generate the alternating face-centered cubic and body-centered cubic interface. The potential was later employed during molecular dynamics compression simulations to accurately portray the behavior of individual atoms. These structures are rst molded into nanowire structures before deformation at 10K under uniaxial compression at a constant strain rate to evaluate the role of layer thickness and interface. The presence of interfaces (e.g., grain boundaries and free surface), and their role in dislocation nucleation within con ned volumes (i.e., nanowires) was then evaluated. Additionally, nanolaminate simulations with identical compositions were compressed using the same parameters to provide a comparison to structures without free surfaces. The simulation data was later applied to provide insightful results on atomic scale deformation. Plastic deformation mechanisms common to nanowires and nanolaminates were analyzed with various metric criteria. The unique deformation mechanisms within each layer and the interaction with the interface drove the compression response. Deformation induced dislocation movement and twin boundary development were specific to individual material layers. Therefore, these mechanisms were responsible for the differing material properties across all combinations. Finally, the rule of mixtures was evaluated to determine whether the unique nanoscale mechanisms were accounted for in the hypothesized material properties.
Download or read book Quantifying the Influence of Twin Boundaries on the Deformation of Nanocrystalline Copper Using Atomistic Simulations written by and published by . This book was released on 2014 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past decade, numerous efforts have sought to understand the influence of twin boundaries on the behavior of polycrystalline materials. Early results suggested that twin boundaries within nanocrystalline face-centered cubic metals have a considerable effect on material behavior by altering the activated deformation mechanisms. In this work, we employ molecular dynamics simulations to elucidate the role of twin boundaries on the deformation of 100 columnar nanocrystalline copper at room temperature under uniaxial strain. We leverage non-local kinematic metrics, formulated from continuum mechanics theory, to compute atomically-resolved rotational and strain fields during plastic deformation. These results are then utilized to compute the distribution of various nanoscale mechanisms during straining, and quantitatively resolve their contribution to the total strain accommodation within the microstructure, highlighting the fundamental role of twin boundaries. Our results show that nanoscale twins influence nanocrystalline copper by altering the cooperation of fundamental deformation mechanisms and their contributed role in strain accommodation, and we present new methods for extracting useful information from atomistic simulations. The simulation results suggest a tension-compression asymmetry in the distribution of deformation mechanisms and strain accommodation by either dislocations or twin boundary mechanisms. In highly twinned microstructures, twin boundary migration can become a significant deformation mode, in comparison to lattice dislocation plasticity in non-twinned columnar microstructures, especially during compression.
Download or read book Atomistic and Continuum Modeling of Nanocrystalline Materials written by Laurent Capolungo and published by Springer Science & Business Media. This book was released on 2010-03-17 with total page 409 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomistic and Continuum Modeling of Nanocrystalline Materials develops a complete and rigorous state-of-the-art analysis of the modeling of the mechanical behavior of nanocrystalline (NC) materials. Among other key topics, the material focuses on the novel techniques used to predict the behavior of nanocrystalline materials. Particular attention is given to recent theoretical and computational frameworks combining atomistic and continuum approaches. Also, the most relevant deformation mechanisms governing the response of nanocrystalline materials are addressed and discussed in correlation with available experimental data.
Download or read book Advances in Nanotechnology Research and Application 2012 Edition written by and published by ScholarlyEditions. This book was released on 2012-12-26 with total page 14170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Nanotechnology Research and Application / 2012 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about Nanotechnology. The editors have built Advances in Nanotechnology Research and Application / 2012 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Nanotechnology in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Advances in Nanotechnology Research and Application / 2012 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Download or read book Molecular Dynamics Simulation of Nanostructured Materials written by Snehanshu Pal and published by CRC Press. This book was released on 2020-05-15 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular dynamics simulation is a significant technique to gain insight into the mechanical behavior of nanostructured (NS) materials and associated underlying deformation mechanisms at the atomic scale. The purpose of this book is to detect and correlate critically current achievements and properly assess the state of the art in the mechanical behavior study of NS material in the perspective of the atomic scale simulation of the deformation process. More precisely, the book aims to provide representative examples of mechanical behavior studies carried out using molecular dynamics simulations, which provide contributory research findings toward progress in the field of NS material technology.
Download or read book Resolving the Contribution of Interfaces in the Deformation of Nanocrystalline Copper with Atomistic Simulations written by and published by . This book was released on 2012 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Shear Deformation of Amorphous and Nanocrystalline Copper Microstructures Via Atomistic Simulation written by David R. Gandy and published by . This book was released on 2007 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the well-known 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 structure is composed of an increasingly high percentage of grain boundaries, which exhibit the properties of an amorphous structure. Molecular dynamics simulations, with the goal of exploring this behavior, were performed on nanocrystalline and amorphous microstructures using the embedded atom potential developed by Mishin et al. A 0.2 shear strain was applied to each of the nanocrystalline and amorphous samples. From these simulations, we have observed the inverse Hall-Petch behavior of nanocrystalline structures. We have also shown that the amorphous structure as zero grain size is reasonable as the limiting case for the inverse Hall-Petch trends in nanocrystalline structures.
Download or read book Atomistic Modeling of Materials Failure written by Markus J. Buehler and published by Springer Science & Business Media. This book was released on 2008-08-07 with total page 547 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an introduction to molecular and atomistic modeling techniques applied to fracture and deformation of solids, focusing on a variety of brittle, ductile, geometrically confined and biological materials. The overview includes computational methods and techniques operating at the atomic scale, and describes how these techniques can be used to model cracks and other deformation mechanisms. The book aims to make new molecular modeling techniques available to a wider community.
Download or read book Atomistic Simulation Studies of Grain Boundary Segregation and Strengthening Mechanisms in Nanocrystalline Nanotwinned Silver Copper Alloys written by Xing Ke and published by . This book was released on 2019 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: Silver (Ag) is a precious metal with a low stacking fault energy that is known to form copious nanoscale coherent twin boundaries during magnetron sputtering synthesis. Nanotwinned Ag metals are potentially attractive for creating new interface-dominated nanomaterials with unprecedented mechanical and physical properties. Grain-boundary segregation of solute elements has been found to increase the stability of interfaces and hardness of nanocrystalline metals. However, heavily alloying inevitably complicates the underlying deformation mechanisms due to the hardening effects of solutes, or a change of stacking fault energies in Ag caused by alloying. For the above reasons, we developed a microalloying (or doping) strategy by carefully selecting Cu as the primary impurity--a solute that is predicted to have no solid-solution strengthening effect in Ag when its content is below 3.0 wt.%. Neither will Cu affect the stacking fault energy of Ag at a concentration
Download or read book Deformation Mechanism in Nanocrystalline FCC Metals Studied by Atomistic Simulations written by Christian Brandl and published by . This book was released on 2010 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polymer Adhesion Friction and Lubrication written by Hongbo Zeng and published by John Wiley & Sons. This book was released on 2013-04-01 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Specifically dedicated to polymer and biopolymer systems, Polymer Adhesion, Friction, and Lubrication guides readers to the scratch, wear, and lubrication properties of polymers and the engineering applications, from biomedical research to automotive engineering. Author Hongbo Zeng details different experimental and theoretical methods used to probe static and dynamic properties of polymer materials and biomacromolecular systems. Topics include the use of atomic force microscopy (AFM) to analyze nanotribology, polymer thin films and brushes, nanoparticles, rubber and tire technology, synovial joint lubrication, adhesion in paper products, bioMEMS, and electrorheological fluids.
Download or read book Machining and Tribology written by Alokesh Pramanik and published by Elsevier. This book was released on 2021-10-16 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Machining and Tribology provides insight into both the role of tribology in machining and the effects of various machining processes on tribology, exploring topics such as machining mechanisms, coolant technology, tool wear, and more. Covering the latest research, the book starts by looking at the tribological aspects of turning, milling, and drilling processes. From there, it explores the effects of different coolants such as flood, minimum quantity lubrication, and cryogenics on machining forces, tool wear, friction, chip formation, and surface generation during various machining processes. Tribological considerations of machined components follow, and the volume concludes with chapters covering simulation scenarios for predicting machining forces, tool wear, surface generation, and chip formation. - Draws upon the science of tribology to better understand, predict, and improve machining processes - Covers tribology in different types of machining such as turning, milling, grinding, abrasive jet machining, and others - Explores the underlying mechanisms of coolant contributions on machining processes - Applies simulation techniques to explore the mechanism of nano-machining
Download or read book The Art of Molecular Dynamics Simulation written by D. C. Rapaport and published by Cambridge University Press. This book was released on 2004-04 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: First time paperback of successful physics monograph. Copyright © Libri GmbH. All rights reserved.
Download or read book Nanotube Superfiber Materials written by Y.J. Liu and published by Elsevier Inc. Chapters. This book was released on 2013-09-16 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this chapter, a hierarchical multiscale approach for modeling carbon nanotube (CNT) composites using molecular dynamics (MD) at the nanoscale and the boundary element method (BEM) at the microscale is presented. First, the current status in modeling and simulations of CNT composites is reviewed. Then, the basics of MD are introduced and the modeling techniques using MD at the nanoscale to extract the CNT properties and a cohesive interface model for CNT/polymer composites are discussed. Next, the boundary integral equations (BIEs) governing the displacement and stress fields in fiber-reinforced composite models at the microscale are presented. The BEM applied to solve the BIEs numerically is discussed and the fast multipole BEM techniques that are suitable for solving large-scale models are presented. In the numerical studies, parameters in the cohesive interface model are obtained by conducting CNT pull-out simulations with MD and these parameters are subsequently used in the BEM models of the CNT/polymer composites. Marked decreases of the estimated effective Young's moduli are observed using the new BEM models with the cohesive interface conditions as compared with earlier models with perfect bonding interface conditions. The developed BEM models combined with the MD can be a very useful tool for studying interface effects in CNT composites and for large-scale characterizations of such nanocomposites. Future efforts and directions in the research on modeling nanocomposites are offered to conclude this chapter.
Download or read book CIRP Annals written by International Institution for Production Engineering Research and published by . This book was released on 1994 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanoscale Effects in the Tribological Properties of Materials a Molecular Dynamics Study written by and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the emergence of technological applications such as magnetic storage devices, MEMS applications and ultra-thin film coatings, the study of friction, adhesion, and wear has become increasingly important. For better design and durability of these nanoscale devices, it is essential to understand deformation in small volumes and in particular how deformation mechanisms can be related to frictional response of an interface in the regime where plasticity is fully developed. However, there is a lack of analytical models that relate tribological response to material properties and/or contact geometry for nanoscale elastic-plastic contacts. To provide these solutions, this thesis focuses on (a) development of analytical models that describe tribological behavior at nanoscale contacts and (b) investigation of atomistic mechanisms that control nanoscale deformation during sliding of elastic-plastic contacts. Large scale molecular dynamics studies of single asperity sliding have been conducted on three different materials: crystalline silicon carbide, crystalline copper and nanocrystalline silicon carbide. We demonstrate that, unlike in a number of other brittle materials, a high pressure phase transformation in SiC is highly unlikely under indentation or cutting conditions. The different categories of dislocation activity are investigated as a function of normal load and depth of cut for single crystal SiC. For nanocrystalline (nc) SiC, deformation is shown to occur via grain boundary sliding, heterogeneous nucleation of partial dislocations, formation of voids at the triple junctions, and grain pull-out. Our results demonstrate that machining of nc ceramics can be performed with nanometer-sized tools because in this regime brittle ceramics are pliable. In addition, we have developed a new analytical model which describes the plowing coefficient of friction during sliding of elastic-plastic contacts between a single asperity and a flat substrate. The proposed model includes the effects of both elastic recovery and pileup. Applicability of the new model is demonstrated on the examples of non-adhesive and adhesive contacts in SiC and Cu. In addition, our model shows excellent agreement with large scale molecular dynamics simulations and AFM experiments of nanoscratching on Cu single crystals.
