Download or read book Molecular Dynamics Simulation of Grain Boundary Migration written by Jian Zhou and published by Cuvillier Verlag. This book was released on 2012-03-05 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Migration of tilt 111 grain boundaries (GBs) in aluminum has been simulated in a wide temperature range with various magnitudes of driving force. It is found that under different conditions GBs migrate through either a diffusionless or a diffusional mechanism. The essence of the diffusionless mechanism is determined to be GB dislocation glide. This mechanism agrees with many previously reported mechanisms, consisting of the collective motion of atom groups, the four-atom shuffling and the boundary motion by glide of primary/secondary GB dislocations. GB dislocation glide therefore serves as a generalized mechanism for all of them. The diffusional mechanism is merely observed to occur for high-angle GBs at high temperatures when a relatively small driving force of several MPa is applied. For these GBs featured in thick and highly disordered structures, GB migration is controlled by GB diffusion. The effects of structural constraints, temperature, GB misorientation and driving force magnitude, on the activation of either mechanism as well as on concrete GB migration behaviors are discussed. Based on these discussions, two GB migration mechanism maps for polycrystals are proposed. The mechanism maps can well explain many contradictory findings obtained previously in both experiments and simulations. In addition, GB mobilities are evaluated at a high temperature. The simulated values are physically reasonable as high-angle GBs move faster than low-angle GBs and the maximum mobility occurs around 40° misorientation. The mobility of a Σ7 GB even approaches the maximum experimental value obtained in ultra-high-purity bicrystals.
Download or read book Molecular Dynamics Simulation of Grain Boundary Motion written by and published by . This book was released on 2015 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Dynamics Simulation of Thermally Activated Grain Boundary Migration written by Tsung-Yih Tsai and published by . This book was released on 1992 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atomistic Simulation of Materials written by David J. Srolovitz and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains proceedings of an international symposium on Atomistic th Simulation of Materials: Beyond Pair Potentials which was held in Chicago from the 25 th to 30 of September 1988, in conjunction with the ASM World Materials Congress. This symposium was financially supported by the Energy Conversion and Utilization Technology Program of the U. S Department of Energy and by the Air Force Office of Scientific Research. A total of fifty four talks were presented of which twenty one were invited. Atomistic simulations are now common in materials research. Such simulations are currently used to determine the structural and thermodynamic properties of crystalline solids, glasses and liquids. They are of particular importance in studies of crystal defects, interfaces and surfaces since their structures and behavior playa dominant role in most materials properties. The utility of atomistic simulations lies in their ability to provide information on those length scales where continuum theory breaks down and instead complex many body problems have to be solved to understand atomic level structures and processes.
Download or read book Influence of Point Defects on Grain Boundary Motion written by and published by . This book was released on 2010 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work addresses the influence of point defects, in particular vacancies, on the motion of grain boundaries. If there is a non-equilibrium concentration of point defects in the vicinity of an interface, such as due to displacement cascades in a radiation environment, motion of the interface to sweep up the defects will lower the energy and provide a driving force for interface motion. Molecular dynamics simulations are employed to examine the process for the case of excess vacancy concentrations in the vicinity of two grain boundaries. It is observed that the efficacy of the presence of the point defects in inducing boundary motion depends on the balance of the mobility of the defects with the mobility of the interfaces. In addition, the extent to which grain boundaries are ideal sinks for vacancies is evaluated by considering the energy of boundaries before and after vacancy absorption.
Download or read book Grain Boundary Migration in Metals written by Hao Zhang and published by . This book was released on 2005 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Grain Boundary Migration in Metals written by Gunter Gottstein and published by CRC Press. This book was released on 1999-06-17 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: The behavior of adjacent materials at the boundary where they meet is an essential aspect of creating new engineering materials. Grain Boundary Migration in Metals is an authoritative account of the physics of grain boundary motion, written by two highly respected researchers. They provide a comprehensive overview of current knowledge regarding the migration process and how it affects microstructure evolution, focusing their treatment exclusively on the properties and behavior of grain boundaries with well defined geometry and crystallography. With their emphasis on applications-such as the characterization of microstructure and texture, recrystallization, and grain growth-the authors effectively fill the gap between the physics of grain boundary motion and its engineering practicality. The need for better microstructural design motivates permanent thrust for research in the field, and continued rapid progress appears inevitable. Grain Boundary Migration in Metals provides a solid foundation in the phenomena and serves as a valuable reference for professionals in materials science, solid state physics, and any industry engaged in metals production and the heat treatment of metals and alloys.
Download or read book Molecular Dynamics Simulations of Grain Boundary and Bulk Diffusion in Metals written by Steven James Plimpton and published by . This book was released on 1989 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 2D and 3D Grain Growth Modeling and Simulation written by Luis Antonio Barrales-Mora and published by Cuvillier Verlag. This book was released on 2008 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interactions Between Grain Boundary Faceting Migration and Grain Rotation written by Yue Huang and published by . This book was released on 2006 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computer Simulation Studies of Grain Boundary Systems and Molecular Solids written by Sidney Yip and published by . This book was released on 1983 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Structural, thermodynamic and mechanical properties of bicrystals have been studied using molecular dynamics and Monte Carlo simulation. A grain boundary melting transition in a two-dimensional system has been observed. Atomic diffusion along grain boundaries was investigated by following in detail the migration of a vacancy initially introduced into the bicrystal. The activation energy for vacancy migration in iron has been determined, and thermal activation of Frenkel pairs in the grain boundary core was observed. Structural phase transformation in stressed solids has been studied using an extended Monte Carlo method. Stress-strain relations obtained for iron showed the existence of bcc - fcc transition under tension or compression. Dynamical properties of a one-dimensional nonlinear lattice (the U4-lattice) have been analyzed in terms of kink propagation and damping and kink diffusion. Both perturbation theory and molecular dynamic calculations were carried out. (Author).
Download or read book Molecular Dynamics Study of Grain Boundary Structure and Properties at High Temperatures written by Saryu Jindal Fensin and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports research involving the development and application of atomistic simulation methods to study the effects of high homologous temperatures on the structural, thermodynamic, kinetic and mechanical properties of grain boundaries in metals. In this work we study two different elemental systems, namely Ni and Cu, and consider a variety of grain boundary structures characterized by different misorientation angles, twist/tilt character and zero-temperature energies. A method to calculate the disjoining potential from molecular dynamics is developed and applied to grain boundaries in Ni. The disjoining potential characterizes the variation in grain-boundary free energy as a function of the width of a premelted interfacial layer. The MD method for the calculation of this property is applied to grain boundaries that display continuous premelting transitions, as well as a boundary characterized by a disordered atomic structure displaying a finite interfacial width at the melting temperature. We also develop analysis methods to characterize the change in the atomic structure of an asymmetric tilt grain boundary in elemental Cu as a function of temperature. This boundary is characterized by a potential-energy surface with multiple minima as a function of the relative translation of the grains parallel to the interface plane. The structure of this boundary is found to display both disordering and roughening with increasing temperature. The mobility was calculated at high homologous temperatures using a method based on the analysis of the random walk of the interface in equilibrium MD simulations. Finally, the temperature dependent response of this grain boundary to shear was investigated. The dynamical behavior of the boundary in response to an applied shear strain was observed to undergo qualitative changes as the temperature was increased above 700 K.A decrease in shear resistance of the grain boundaries as a function of temperature was characterized by a decrease in the critical shear stress, an upper bound for which was estimated to be roughly a factor of five lower at the melting temperature than at zero temperature.
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 Computer Molecular Dynamics Studies of Grain Boundary Structures I Observations of Coupled Sliding and Migration in a Three Dimensional Simulation written by George H Bishop (Jr) and published by . This book was released on 1981 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interfaces in Crystalline Materials written by A.P. Sutton and published by OUP Oxford. This book was released on 2006-12-21 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of interfaces within and between materials is a central field which is relevant to almost all aspects of materials science. This book is intended to serve as a graduate text consisting of four inter-related parts spanning the structure, thermodynamics, kinetics, and properties of interfaces in crystalline materials.
Download or read book Thermodynamic and Kinetic Grain Boundary Properties Investigated by Molecular Dynamics Simulations written by Adrian Alexander Schratt and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Simulation in Molecular Dynamics written by Michael Griebel and published by Springer Science & Business Media. This book was released on 2007-08-16 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book details the necessary numerical methods, the theoretical background and foundations and the techniques involved in creating computer particle models, including linked-cell method, SPME-method, tree codes, amd multipol technique. It illustrates modeling, discretization, algorithms and their parallel implementation with MPI on computer systems with distributed memory. The text offers step-by-step explanations of numerical simulation, providing illustrative code examples. With the description of the algorithms and the presentation of the results of various simulations from fields such as material science, nanotechnology, biochemistry and astrophysics, the reader of this book will learn how to write programs capable of running successful experiments for molecular dynamics.
