Dislocation Dynamics Simulations of Plasticity in Cu Thin Films

Dislocation Dynamics Simulations of Plasticity in Cu Thin Films PDF Author: Han Wu
Publisher:
ISBN:
Category : Deformations (Mechanics)
Languages : en
Pages : 47

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Dislocation Dynamics Simulations of Plasticity in Cu Thin Films

Dislocation Dynamics Simulations of Plasticity in Cu Thin Films PDF Author: Han Wu
Publisher:
ISBN:
Category : Deformations (Mechanics)
Languages : en
Pages : 47

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Book Description


Dislocation Dynamics and Plasticity in Micropillars and Thin Films

Dislocation Dynamics and Plasticity in Micropillars and Thin Films PDF Author: Christopher Robert Weinberger
Publisher:
ISBN:
Category :
Languages : en
Pages : 352

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Dislocation Dynamics Simulations of Plasticity at Small Scales

Dislocation Dynamics Simulations of Plasticity at Small Scales PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 179

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Book Description
As metallic structures and devices are being created on a dimension comparable to the length scales of the underlying dislocation microstructures, the mechanical properties of them change drastically. Since such small structures are increasingly common in modern technologies, there is an emergent need to understand the critical roles of elasticity, plasticity, and fracture in small structures. Dislocation dynamics (DD) simulations, in which the dislocations are the simulated entities, offer a way to extend length scales beyond those of atomistic simulations and the results from DD simulations can be directly compared with the micromechanical tests. The primary objective of this research is to use 3-D DD simulations to study the plastic deformation of nano- and micro-scale materials and understand the correlation between dislocation motion, interactions and the mechanical response. Specifically, to identify what critical events (i.e., dislocation multiplication, cross-slip, storage, nucleation, junction and dipole formation, pinning etc.) determine the deformation response and how these change from bulk behavior as the system decreases in size and correlate and improve our current knowledge of bulk plasticity with the knowledge gained from the direct observations of small-scale plasticity. Our simulation results on single crystal micropillars and polycrystalline thin films can march the experiment results well and capture the essential features in small-scale plasticity. Furthermore, several simple and accurate models have been developed following our simulation results and can reasonably predict the plastic behavior of small scale materials.

Dislocation Mechanism-Based Crystal Plasticity

Dislocation Mechanism-Based Crystal Plasticity PDF Author: Zhuo Zhuang
Publisher: Academic Press
ISBN: 0128145927
Category : Technology & Engineering
Languages : en
Pages : 450

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Book Description
Dislocation Based Crystal Plasticity: Theory and Computation at Micron and Submicron Scale provides a comprehensive introduction to the continuum and discreteness dislocation mechanism-based theories and computational methods of crystal plasticity at the micron and submicron scale. Sections cover the fundamental concept of conventional crystal plasticity theory at the macro-scale without size effect, strain gradient crystal plasticity theory based on Taylar law dislocation, mechanism at the mesoscale, phase-field theory of crystal plasticity, computation at the submicron scale, including single crystal plasticity theory, and the discrete-continuous model of crystal plasticity with three-dimensional discrete dislocation dynamics coupling finite element method (DDD-FEM). Three kinds of plastic deformation mechanisms for submicron pillars are systematically presented. Further sections discuss dislocation nucleation and starvation at high strain rate and temperature effect for dislocation annihilation mechanism. Covers dislocation mechanism-based crystal plasticity theory and computation at the micron and submicron scale Presents crystal plasticity theory without size effect Deals with the 3D discrete-continuous (3D DCM) theoretic and computational model of crystal plasticity with 3D discrete dislocation dynamics (3D DDD) coupling finite element method (FEM) Includes discrete dislocation mechanism-based theory and computation at the submicron scale with single arm source, coating micropillar, lower cyclic loading pillars, and dislocation starvation at the submicron scale

Dislocation Dynamics and Plasticity

Dislocation Dynamics and Plasticity PDF Author: Taira Suzuki
Publisher: Springer Science & Business Media
ISBN: 364275774X
Category : Science
Languages : en
Pages : 237

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Book Description
In the 1950s the direct observation of dislocations became possible, stimulat ing the interest of many research workers in the dynamics of dislocations. This led to major contributions to the understanding of the plasticity of various crys talline materials. During this time the study of metals and alloys of fcc and hcp structures developed remarkably. In particular, the discovery of the so-called in ertial effect caused by the electron and phonon frictional forces greatly influenced the quantitative understanding of the strength of these metallic materials. Statis tical studies of dislocations moving through random arrays of point obstacles played an important role in the above advances. These topics are described in Chaps. 2-4. Metals and alloys with bcc structure have large Peierls forces compared to those with fcc structure. The reasons for the delay in studying substances with bcc structure were mostly difficulties connected with the purification techniques and with microscopic studies of the dislocation core. In the 1970s, these difficulties were largely overcome by developments in experimental techniques and computer physics. Studies of dislocations in ionic and covalent bonding materials with large Peierls forces provided infonnation about the core structures of dislocations and their electronic interactions with charged particles. These are the main subjects in Chaps. 5-7.

Continuum Scale Simulation of Engineering Materials

Continuum Scale Simulation of Engineering Materials PDF Author: Dierk Raabe
Publisher: John Wiley & Sons
ISBN: 3527604219
Category : Technology & Engineering
Languages : en
Pages : 885

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Book Description
This book fills a gap by presenting our current knowledge and understanding of continuum-based concepts behind computational methods used for microstructure and process simulation of engineering materials above the atomic scale. The volume provides an excellent overview on the different methods, comparing the different methods in terms of their respective particular weaknesses and advantages. This trains readers to identify appropriate approaches to the new challenges that emerge every day in this exciting domain. Divided into three main parts, the first is a basic overview covering fundamental key methods in the field of continuum scale materials simulation. The second one then goes on to look at applications of these methods to the prediction of microstructures, dealing with explicit simulation examples, while the third part discusses example applications in the field of process simulation. By presenting a spectrum of different computational approaches to materials, the book aims to initiate the development of corresponding virtual laboratories in the industry in which these methods are exploited. As such, it addresses graduates and undergraduates, lecturers, materials scientists and engineers, physicists, biologists, chemists, mathematicians, and mechanical engineers.

Dislocation Dynamics

Dislocation Dynamics PDF Author: Alan R. Rosenfield
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 808

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Dislocations and Strength in Thin Films

Dislocations and Strength in Thin Films PDF Author: Ray Stuart Fertig
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Single-crystal films were simulated using three-dimensional discrete dislocation dynamics simulations, where an initial distribution of dislocation loops was allowed to move naturally in response to successive applied strains. The types of interactions that stopped threading dislocations (threads) were identified and the relative fraction of threads stopped in each interaction was determined. An inhomogeneous stress field in the film evolved as the dislocation structure evolved. Threads were observed to interact primarily in regions of low stress. The simulations were used as a virtual test bed for understanding dislocation behavior in thin films. The intuition gained from the simulations led to the construction of three models, which are discussed in detail. First, a model was developed to determine the capture cross-section of a thread, such that if another thread was within its capture cross-section the two threads would interact. Second, a statistical model was constructed to evaluate the effect of stress inhomogeneity on the local concentration of threads. Finally, results from the simulations and analytical models were used to construct a model of strain hardening in thin films based on fundamental behavior of dislocations in thin films.

Dislocations, Mesoscale Simulations and Plastic Flow

Dislocations, Mesoscale Simulations and Plastic Flow PDF Author: L. Kubin
Publisher: Oxford University Press (UK)
ISBN: 019852501X
Category : Science
Languages : en
Pages : 320

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Book Description
In the past twenty years, new experimental approaches, improved models and progress in simulation techniques brought new insights into long-standing issues concerning dislocation-based plasticity in crystalline materials. Dislocation dynamics simulations are becoming accessible to a wide range of users. This book presents to students and researchers in materials science and mechanical engineering a comprehensive coverage of the physical body of knowledge on whichthey are based. This includes classical studies, which are too often ignored, recent experimental and theoretical advances, as well as a discussion of selected applications on various topics.

Dislocation Interactions in Thin Films

Dislocation Interactions in Thin Films PDF Author: Prita Pant
Publisher:
ISBN:
Category : Deformations (Mechanics)
Languages : en
Pages : 410

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