Download or read book Investigating the Evolution of Grain Scale Microstructure During Large Plastic Deformation of Polycrystalline Aluminum written by Abhishek Bhattacharyya and published by . This book was released on 2002 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Large Plastic Deformation of Crystalline Aggregates written by Cristian Teodosiu and published by Springer. This book was released on 2014-05-04 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book gives a comprehensive view of the present ability to take into account the microstructure and texture evolution in building up engineering models of the plastic behaviour of polycrystalline materials at large strains. It is designed for postgraduate students, research engineers and academics that are interested in using advanced models of the mechanical behaviour of polycrystalline materials.

Download or read book Simulating Microstructure Evolution of Realistic 3D Aluminum Alloy Polycrystal During Large Plastic Deformation at Elevated Temperature written by Jing Lu and published by . This book was released on 2006 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Crystal Plasticity Finite Element Methods written by Franz Roters and published by John Wiley & Sons. This book was released on 2011-08-04 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by the leading experts in computational materials science, this handy reference concisely reviews the most important aspects of plasticity modeling: constitutive laws, phase transformations, texture methods, continuum approaches and damage mechanisms. As a result, it provides the knowledge needed to avoid failures in critical systems udner mechanical load. With its various application examples to micro- and macrostructure mechanics, this is an invaluable resource for mechanical engineers as well as for researchers wanting to improve on this method and extend its outreach.

Download or read book Integrated Computational Materials Engineering ICME written by Somnath Ghosh and published by Springer Nature. This book was released on 2020-03-20 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: ​This book introduces research advances in Integrated Computational Materials Engineering (ICME) that have taken place under the aegis of the AFOSR/AFRL sponsored Center of Excellence on Integrated Materials Modeling (CEIMM) at Johns Hopkins University. Its author team consists of leading researchers in ICME from prominent academic institutions and the Air Force Research Laboratory. The book examines state-of-the-art advances in physics-based, multi-scale, computational-experimental methods and models for structural materials like polymer-matrix composites and metallic alloys. The book emphasizes Ni-based superalloys and epoxy matrix carbon-fiber composites and encompasses atomistic scales, meso-scales of coarse-grained models and discrete dislocations, and micro-scales of poly-phase and polycrystalline microstructures. Other critical phenomena investigated include the relationship between microstructural morphology, crystallography, and mechanisms to the material response at different scales; methods of identifying representative volume elements using microstructure and material characterization, and robust deterministic and probabilistic modeling of deformation and damage. Encompassing a slate of topics that enable readers to comprehend and approach ICME-related issues involved in predicting material performance and failure, the book is ideal for mechanical, civil, and aerospace engineers, and materials scientists, in in academic, government, and industrial laboratories.

Download or read book Recrystallization and Related Annealing Phenomena written by F.J. Humphreys and published by Elsevier. This book was released on 2012-12-02 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: The annealing of deformed materials is of both technological importance and scientific interest. The phenomena have been most widely studied in metals, although they occur in all crystalline materials such as the natural deformation of rocks and the processing of technical ceramics. Research is mainly driven by the requirements of industry, and where appropriate, the book discusses the extent to which we are able to formulate quantitative, physically-based models which can be applied to metal-forming processes.The subjects treated in this book are all active research areas, and form a major part of at least four regular international conference series. However, there have only been two monographs published in recent times on the subject of recrystallization, the latest nearly 20 years ago. Since that time, considerable advances have been made, both in our understanding of the subject and in the techniques available to the researcher.The book covers recovery, recrystallization and grain growth in depth including specific chapters on ordered materials, two-phase alloys, annealing textures and annealing during and after hot working. Also contained are treatments of the deformed state and the structure and mobility of grain boundaries, technologically important examples and a chapter on computer simulation and modelling. The book provides a scientific treatment of the subject for researchers or students in Materials Science, Metallurgy and related disciplines, who require a more detailed coverage than is found in textbooks on physical metallurgy, and a more coherent treatment than will be found in the many conference proceedings and review articles.

Download or read book Production of Ultra Fine Grains and Evolution of Grain Boundaries During Severe Plastic Deformation of Aluminum and Its Alloys written by Douglas L. Swisher and published by . This book was released on 2000-12-01 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: Equal channel-angular pressing (ECAP) is a recently developed method for deformation processing of material that can produce an ultra-fine grain structure in bulk material through severe plastic deformation. This study will present results on micro structural evolution during repetitive ECAP of pure aluminum. The principal method of data collection was Orientation Imaging Microscopy (OIM). The results of the study indicate that, after one ECAP pass, the structure is inhomogeneous and anisotropic, and consists mostly of deformation-induced features. After repetitive ECAP, the aluminum material exhibited a homogeneous grain size but retained an anisotropic character to the microstructure. After twelve ECAP passes the microstructure consisted mainly of fine grains surrounded by high-angle boundaries but an appreciable fraction of low-angle boundaries remained. This microstructure thus comprises a mixture of deformation-induced and recrystallization features. Further results were also obtained documenting the existence of deformation banding in this material as well as in a rolled aluminum alloy. This phenomenon may be general in nature and associated with severe plastic deformation in aluminum and its alloys.

Download or read book Computational Materials Science written by Dierk Raabe and published by Wiley-VCH. This book was released on 1998-10-27 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling and simulation play an ever increasing role in the development and optimization of materials. Computational Materials Science presents the most important approaches in this new interdisciplinary field of materials science and engineering. The reader will learn to assess which numerical method is appropriate for performing simulations at the various microstructural levels and how they can be coupled. This book addresses graduate students and professionals in materials science and engineering as well as materials-oriented physicists and mechanical engineers.

Download or read book Modelling Microstructure property Relationships in Polycrystalline Metals Using New Fast Fourier Transform based Crystal Plasticity Frameworks written by Jaspreet Singh Nagra and published by . This book was released on 2019 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present thesis develops several new full-field, fast Fourier transform (FFT)-based crystal plasticity modelling tools for microstructure engineering. These tools are used to explore elasto-viscoplastic deformation, localized deformation, 3D grain morphology, microstructure evolution, dynamic recrystallization and their effects on formability of polycrystalline metals with particular attention paid to sheet alloys of aluminum and magnesium. The new FFT-based crystal plasticity models developed in this work overcome several inherent problems present in the well-known crystal plasticity finite element method (CP-FEM) and elasto-viscoplastic fast Fourier transform method (EVP-FFT) in solving representative volume element (RVE)-based problems. The new models have demonstrated significant fidelity in simulating various deformation phenomena in polycrystalline metals and prove to be faster and accurate alternatives for obtaining full-field solutions of micromechanical fields in aluminum and magnesium sheet alloys. In particular to the aluminum alloys, which are currently replacing heavier steel parts in the automotive industry, the sheet aluminum alloys have significantly improved corrosion resistance and strength-to-weight properties in comparison to steel. However, aluminum alloys are still outperformed by steel in terms of formability. To improve the formability of an aluminum sheet, one method is to develop physics-based predictive computational tools, which can accurately and efficiently predict the behavior of aluminum alloys and thus allow designing the microstructure with desired properties. Accordingly, in first part of this thesis, a novel numerical framework for modelling large deformation in aluminum alloys is developed. The developed framework incorporates the rate-dependent crystal plasticity theory into the fast Fourier transform (FFT)-based formulation, and this is named as rate tangent crystal plasticity-based fast Fourier transform (i.e., RTCP-FFT) framework. This framework is used as a predictive tool for obtaining stress-strain response and texture evolution in new strain-paths with minimal calibration for aluminum alloys. The RTCP-FFT framework is benchmarked against an existing FFT-based model at small strains and finite element-based model at large strains, respectively, for the case of an artificial Face Centered Cubic (FCC) polycrystal. The predictive capability as well as the computational efficiency of the developed framework are then demonstrated for aluminum alloy (AA) 5754. In the second part of this thesis, the RTCP-FFT framework, developed earlier, is coupled with the Marciniak and Kuczynski (MK) approach to establish a new full-field framework for generating forming limit diagrams (FLDs) of aluminum sheet alloys, e.g., AA3003 and AA5754. The new coupled framework is able to investigate the complex effects of grain morphology, local deformation, local texture and grain interactions on the predictions of forming limit strains. This study reveals that among the various microstructural features, the grain morphology has the strongest effect on the predicted FLDs for aluminum alloys. Furthermore, this study also suggests that the FLD predictions can be significantly improved if the actual grain structure of the material is properly accounted for in the crystal plasticity models. In addition to aluminum alloys, magnesium alloys are getting significant attention by the automotive industry due to their light weight and high specific strength. However, the automotive industry has not been able to take full advantage of the lightweight characteristic of magnesium alloys because of their poor formability at room temperature. Therefore, to enhance the workability and restore their ductility, the magnesium alloys are formed at elevated temperature. High temperature forming of magnesium alloys is often accompanied by dynamic recrystallization (DRX), which allows the final microstructure, as well as the properties of the material (e.g., initial grain size, initial texture, etc.), to be controlled. Therefore, DRX coupled with a full-field crystal plasticity FLD framework can be used as a tool to design microstructure of a material. Since it would be beneficial to be able to redesign the material properties of magnesium alloys using physics-based computational tools than using physical experiments, this work takes a step ahead towards such an outcome by presenting a new framework that predicts DRX and models its effects on the formability of magnesium alloys. Accordingly, in the third part of this thesis, a new full-field, efficient and mesh-free numerical framework, to model microstructure evolution, dynamic recrystallization (DRX) and formability in hexagonal closed-packed (HCP) metals such as magnesium alloys at warm temperatures, is developed. This coupled framework combines three new FFT-based approaches, namely: (a) crystal plasticity modelling of HCP alloys, (b) DRX model, and (c) MK model. First, a rate tangent-fast Fourier transform-based elasto-viscoplastic crystal plasticity constitutive model for HCP metals (RTCP-FFT-HCP) is developed. Then, it is coupled with a probabilistic cellular automata (CA) approach to model DRX. Furthermore, this new model is coupled with the Marciniak-Kuczynski (M-K) approach to model formability of magnesium alloys at elevated temperatures. The RTCP-FFT-HCP model computes macro stress-strain response, twinning volume fraction, micromechanical fields, texture evolution and local dislocation density. Nucleation of new grains and their subsequent growth is modeled using the cellular automata approach with probabilistic state switching rule. This framework is validated at each level of the coupling for magnesium sheet alloy, AZ31. First, the RTCP-FFT-HCP model is validated by comparing the simulated macro stress-strain responses under uniaxial tension and compression with experimental measurements at room temperature. Furthermore, the texture evolution predicted with the new model is compared with experiments. The predictions show a good agreement with experiments with high degree of accuracy. Next, the forming limit diagrams (FLDs) are simulated at 100 C, 200 C and 300 C, respectively, for AZ31 sheet alloy considering the effects of DRX. The predicted FLDs show very good agreement with the experimental measurements. The study reveals that the DRX strongly affects the deformed grain structure, grain size and texture evolution and also highlights the importance accounting for DRX during FLD simulations at high temperatures.

Download or read book Nanomaterials by Severe Plastic Deformation written by Michael J. Zehetbauer and published by John Wiley & Sons. This book was released on 2006-03-06 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings of the "Second International Conference on Nanomaterials by Severe Plastic Deformation" review the enormous scientific avalanche that has been developing in the field over recent years. A valuable resource for any scientist and engineer working in this emerging field of nanotechnology.

Download or read book Light Metals 2013 written by Barry Sadler and published by John Wiley & Sons. This book was released on 2013-02-21 with total page 1410 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Light Metals series is widely recognized as the definitive source of information on new developments in aluminum production technology. This new volume presents proceedings from 2013's Light Metal Symposia, covering the latest research and technologies on such areas as alumina and bauxite, aluminum reduction technology, electrode technology for aluminum production, cast shop for aluminum production, aluminum processing aluminum alloys, and cost affordable titanium IV. It also includes papers from a keynote presentation session discussing impurities in the aluminum supply chain are also included.

Download or read book Grain Subdivision and Microstructural Interfacial Scale Effects in Polycrystalline Materials written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The major objective of this research is to develop a unified physically-based representation of the microstructure in f.c.c. crystalline materials to investigate finite inelastic deformation and failure modes and scenarios at different physical scales that occur due to a myriad of factors, such as texture, grain size and shape, grain subdivision, heterogeneous microstructures, and grain boundary misorientations and distributions. The microstructurally-based formulation for inelastic deformation is based on coupling a multiple-slip crystal plasticity formulation to three distinct dislocation densities, which pertain to statistically stored dislocations (SSDs), geometrically necessary dislocations (GNDs), and grain boundary dislocations (GBDs). This dislocation density based multiple-slip crystal plasticity formulation is then coupled to specialized finite-element methods to predict the scale-dependent microstructural behavior, the evolving heterogeneous microstructure, and the localized phenomena that may contribute to failure initiation for large inelastic strains. The SSD densities provide a representation of cell-type dislocation microstructures and their related processes. The GND densities provide an understanding of the scale-dependent deformation behavior of crystalline materials as a function of grain and aggregate sizes. The GBD densities are formulated to represent the misfit dislocations that arise due to lattice misorientations across GBs, and to provide a framework to investigate the phenomena associated with the grain boundary orientations and distributions. This provides a local criterion of how GB interfaces, such as triple junctions are potential sites for failure initiation and localized behavior. The evolution of the GNDs is used to predict and understand how crystallographic and non-crystallographic microstructures relate to intragranular and intergranular deformation patterns and behavior. Furthermore, a clear understanding of how GB strength cha.

Download or read book Large Plastic Deformations Fundamental Aspects and Applications to Metal Forming written by J.L. Raphanel and published by Routledge. This book was released on 2021-09-17 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume covers topics involving large plastic deformation of metallic materials. These proceedings offer an overview of the synergism achieved by combining microstructural characterization and understanding, mechanical modelling and experiments, numerical analysis and computation.

Download or read book Magnesium Alloys and Their Applications written by Barry L. Mordike and published by . This book was released on 1998 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational Materials Engineering written by Koenraad George Frans Janssens and published by Academic Press. This book was released on 2010-07-26 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational Materials Engineering is an advanced introduction to the computer-aided modeling of essential material properties and behavior, including the physical, thermal and chemical parameters, as well as the mathematical tools used to perform simulations. Its emphasis will be on crystalline materials, which includes all metals. The basis of Computational Materials Engineering allows scientists and engineers to create virtual simulations of material behavior and properties, to better understand how a particular material works and performs and then use that knowledge to design improvements for particular material applications. The text displays knowledge of software designers, materials scientists and engineers, and those involved in materials applications like mechanical engineers, civil engineers, electrical engineers, and chemical engineers. Readers from students to practicing engineers to materials research scientists will find in this book a single source of the major elements that make up contemporary computer modeling of materials characteristics and behavior. The reader will gain an understanding of the underlying statistical and analytical tools that are the basis for modeling complex material interactions, including an understanding of computational thermodynamics and molecular kinetics; as well as various modeling systems. Finally, the book will offer the reader a variety of algorithms to use in solving typical modeling problems so that the theory presented herein can be put to real-world use. - Balanced coverage of fundamentals of materials modeling, as well as more advanced aspects of modeling, such as modeling at all scales from the atomic to the molecular to the macro-material - Concise, yet rigorous mathematical coverage of such analytical tools as the Potts type Monte Carlo method, cellular automata, phase field, dislocation dynamics and Finite Element Analysis in statistical and analytical modeling

Download or read book Experimental Investigation and Multi scale Modeling of Strain Localization Shear Banding and Fracture in Precipitation Hardened Aluminum Alloys written by Waqas Muhammad and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Finite element (FE) simulations are widely used in automotive design processes to model the forming and crashworthiness behavior of structural materials. Comprehensive material characterization and the availability of suitable constitutive models are prerequisites for accurate modeling of these operations. Numerical modeling of formability and crashworthiness is complex as it involves large deformations, instability, ruptures, damage propagation, and fracture. The effectiveness of computer-aided engineering (CAE) based design and performance evaluations significantly depends on the ability of numerical models to predict the material work hardening behavior, flow localization and fracture. This thesis presents a combined experimental and numerical study to explore microstructure property relationships involving strain localization, shear banding and fracture in precipitation hardened aluminum alloys. More specifically, the AA6xxx series aluminum alloys are of key interest for automotive applications, requiring good formability, hemmability and crash energy absorption characteristics. The goal of this work is to enhance the existing experimental understanding and modeling capabilities with respect to strain localization, shear banding and fracture in AA6xxx series precipitation hardened aluminum alloys, through development and coupling of multiscale modeling frameworks with advanced constitutive models for material work hardening and failure. In these regards, a crystal plasticity based constitutive hardening model is developed to account for the intragranular backstresses that arise from the formation of deformation induced dislocation substructure in precipitation hardened aluminum alloys. Based on thorough experimental investigation, it is learned that the substructure starts as pinned dislocation tangles with some regions having relatively high dislocation content while others being virtually dislocation free. With persistent deformation the substructure evolves into a well defined equiaxed cell/subgrain structure with majority of dislocations being trapped at the subgrain cell wall boundaries. The substructure induces intragranular backstresses due to blockage of dislocation passage leading to the experimentally observed Bauschinger effect at the macroscopic scale. The proposed hardening model accounts for these induced stresses and successfully predicts the experimentally measured flow behavior during cyclic simple shear and cyclic TCT and CTC loadings of AA6063. More importantly, the new backstress hardening model successfully reproduces the experimentally observed Bauschinger effect upon loading reversal. It is further shown that the crystallographic texture evolves significantly during cyclic simple shear deformation and the model successfully predicts the experimentally observed texture evolution. The study reveals that for proper prediction of flow behavior and the experimentally observed Bauschinger effect in precipitation hardened aluminum alloys, a physically motivated model that can account for the induced internal stresses, must be employed to describe material hardening on a polycrystalline level. Next, a multiscale modeling approach is developed where a macro-scale component level simulation is performed using conventional phenomenological plasticity and the boundary conditions of the region of interest are extracted and applied to the crystal plasticity based finite element model to account for the relevant microstructural physics. The proposed approach is successfully validated by simulating wrap-bending deformation of AA6063 and by comparing the observed texture evolution, slip band formation within grains, through thickness strain localization and the development of surface roughness with corresponding experimental data. The proposed approach enhances existing modeling capabilities for better predictability of material response under complex loading paths. After developing the multiscale framework, a new constitutive approach is developed to predict failure by extending the existing nano-void theory of ductile failure to precipitation hardened aluminum alloys by accounting for the effects of precipitation induced dislocation substructure on point defect generation. A new evolution law for the effective obstacle strength associated with substructure evolution is incorporated into the formulation. The proposed failure criterion is successfully validated against experimental data and its versatility is demonstrated by coupling the failure criterion with stress-strain data generated through crystal plasticity simulations, to predict failure strain for arbitrary loading - stress triaxiality conditions. Next, a comprehensive experimental investigation is performed to study the relationship between microstructure, plastic deformation and fracture behavior of precipitation hardened aluminum alloy AA6016 during bending. It is shown that the bendability of AA6016 alloy is limited by the formation of severe surface undulations and surface cracking, which are associated with the heterogenous nature of slip concentrating into coarse slip bands and intense shear banding originating from surface low cusps in the form of mutually orthogonal transgranular bands. Micro-cracks originate from low cusp regions along the outer tensile surface and propagate along the intensely sheared planes within shear bands. Results show that grains with S texture component are prone to shear banding and failure during bending and the contrary is true for Cube oriented grains. It is observed that intergranular micro-void nucleation and crack propagation is favored in areas with high grain boundary misorientations and intense slip band impingements along boundaries, perhaps due to the reduction in local cohesive strength of such boundaries. Finally, the developed multiscale modeling approach in conjunction with the newly developed hardening and failure models for age-hardenable aluminum alloys are applied to predict the experimentally observed shear banding and fracture behavior of AA6016 during bending. The simulated results successfully predict the experimentally observed shear banding and the predominant transgranular fracture behavior. It is shown that the advancing crack tip alternates from a less critical localization condition to a more critical one, as it requires lesser energy for the creation of new fracture surfaces while still sustaining the imposed plastic deformation. It is observed that Copper, Brass and Cube texture components show good resistance to shear banding and are therefore characterized as high bendability components, whereas the contrary is true for the S texture component. Lastly, the coupled numerical framework, presented herein, provides an excellent tool for CAE, virtual material characterization and analysis of microstructure-property relationships.

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.