Download or read book Mechanical Flow Response and Anisotropy of Ultra fine Grained Magnesium and Zinc Alloys written by Majid H. Al Maharbi and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hexagonal closed packed (hcp) materials, in contrast to cubic materials, possess several processing challenges due to their anisotropic structural response, the wide variety of deformation textures they exhibit, and limited ductility at room temperature. The aim of this work is to investigate, both experimentally and theoretically, the effect os severe plastic deformation, ultrafine grain sizes, crystallographic textures and number of phases on the flow stress anisotropy and tension compression asymmetry, and the mechanisms responsible for these phenomena in two hcp materials: AZ31B Mg alloy consisting of one phase and Zn-8wt.% Al that has an hcp matrix with a secondary facecentered cubic (fcc) phase. Mg and its alloys have high specific strength that can potentially meet the high demand for light weight structural materials and low fuelconsumption in transportation. Zn-Al alloys, on the other hand, can be potential substitutes for several ferrous and non-ferrous materials because of their good mechanical and tribological properties. Both alloys have been successfully processed using equal channel angular extrusion (ECAE) following different processing routes in order to produce samples with a wide variety of microstructures and crystallographic textures for revealing the relationship between microstructural parameters, crystallographic texture and resulting flow stress anisotropy at room temperature. For AZ31B Mg alloy, the texture evolution during ECAE following conventional and hybrid ECAE routes was successfully predicted using visco-plastic self-consistent (VPSC) crystal plasticity model. The flow stress anisotropy and tension-compression (T/C) asymmetry of the as received and processed samples at room temperature were measured and predicted using the same VPSC model coupled with a dislocation-based hardening scheme. The governing mechanisms behind these phenomena are revealed as functions of grains size and crystallographic texture. It was found that the variation in flow stress anisotropy and T/C asymmetry among samples can be explained based on the texture that is generated after each processing path. Therefore, it is possible to control the flow anisotropy and T/C asymmetry in this alloy and similar Mg alloys by controlling the processing route and number of passes, and the selection of processing conditions can be optimized using VPSC simulations. In Zn-8wt.% Al alloy, the hard phase size, morphology, and distribution were found to control the anisotropy in the flow strength and elongation to failure of the ECAE processed samples.
Download or read book Effect of Texture on Formability and Mechanical Anisotropy of a Severe Plastically Deformed Magnesium Alloy written by Sonia Modarres Razavi and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnesium and its alloys have been considered as alternatives to aluminum alloys and steels for structural applications in automotive and aerospace applications due to their superior specific strength and light-weight. However, they have hexagonal-close packed (hcp) structure, and thus have a small number of deformation systems resulting in low ductility and formability near room temperature, anisotropic thermo-mechanical response and strong deformation textures. The aim of this work is to investigate experimentally the effect of crystallographic texture generated during severe plastic deformation (SPD), on the subsequent formability and mechanical flow anisotropy in AZ31B Mg alloy. The proper control of grain size and texture through SPD is expected to result in better low temperature formability and better control of mechanical flow anisotropy. AZ31B Mg alloy has been successfully processed using equal channel angular extrusion (ECAE) following different processing routes, multiple passes, and different processing temperatures, in order to obtain samples with a wide variety of grain sizes, ranging from ~370 nm up to few microns, and crystallographic textures. Low temperature processing of the AZ31B Mg alloy was successful after initial high temperature processing. Smaller grain sizes were achieved using the temperature step-down method leading to incremental reduction in grain size at each ECAE pass. The temperature step-down method was utilized to develop hybrid ECAE routes to obtain specific crystallographic textures. Optimized hybrid ECAE routes were developed which resulted in a high strength/high ductility material with the average grain size of ~370 nm. The ECAE processed alloy showed a high tensile yield strength of ~380 MPa that has never been reported so far in AZ31 ingot metallurgy Mg alloys. The influence of grain size on the critical stress for the activation of individual deformation mechanisms was also investigated by systematically controlling the texture and grain size, and assuming the activation of mainly a single deformation mechanism through the careful selection of the loading direction on the processed samples. It was revealed that the Hall-Petch slope for the basal slip was much smaller than those of prismatic slip and tensile twinning.
Download or read book Multi scale Investigation on Microstructure Mechanical Properties and Deformation Mechanisms in Mg Alloys written by Dalong Zhang and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Mg and its alloys are promising candidates for light-weight structural applications, e.g., aircraft, automobile, electronic, etc. However, the inherent hexagonal close packed crystal structure makes the deformation of Mg anisotropic, namely deformation only occurs predominantly by dislocation slip in the close-packed (0001) plane (i.e., basal plane), or by deformation twinning in {101̄2} planes. Both basal slip and twinning cause the crystal to re-orient. Consequently, polycrystalline Mg alloys that have undergone thermomechanical processing usually contain strong texture, i.e., preferred crystallographic orientation in grains. The texture in turn leads to anisotropic deformation in wrought Mg alloys. For example, in extruded Mg alloys, the compressive yield strength is usually much lower than the tensile yield strength (so-called yield asymmetry and strength differential). It is the anisotropy that hinders the broader application of Mg alloys. Recent modeling studies on Mg predict that certain alloying elements, particularly rare-earth elements (e.g., Y, Ce, Nd, Gd, etc.), could alter the active deformation modes and enhance homogeneous deformation and overall mechanical properties in Mg. Therefore, the objective of this dissertation research is to investigate experimentally the effects of alloying element Y in reducing the intrinsic and extrinsic anisotropy, modifying texture, and enhancing the overall strength and ductility for Mg. In addition, the research also uncovered some unexpected "side effects" of Y and these phenomena were studied and explained from a fundamental perspective. The methodology used in this work is described as follows. Ultrafine grained Mg 2.5 at.% Y alloy (UFG Mg-2.5Y) was prepared by powder metallurgy method, including gas atomization for producing Mg-2.5Y powder, degassing and hot isostatic pressing (HIP), and hot extrusion. Both the as-HIPed and the as-extruded materials were characterized by electron back-scattered diffraction (EBSD), transmission electron microscopy (TEM), and/or atom probe tomography (APT). It is noted that different configurations of stacking faults (all in basal plane, i.e., basal stacking faults, BSFs for short) were observed in the as-extruded Mg-2.5Y, whereas no BSFs were documented in the as-HIPed alloy. Feasible models to explain the formation of BSFs were proposed based on the activity of different dislocations. Tension and compression tests were carried out along the extrusion direction (ED) for UFG Mg-2.5Y. Unlike common Mg alloys exhibiting yield asymmetry, the UFG Mg-2.5Y exhibits yield "symmetry" and significantly reduced strength differential. Namely, the deformation is more isotropic. In addition to post-mortem TEM characterization for deformed UFG Mg-2.5Y, in-situ TEM was also performed, in an effort to understand the fundamental deformation mechanisms in UFG Mg-Y that lead to reduced anisotropy. In-situ TEM for single-crystal Mg-Y nano-pillars reveals that deformation twinning is replaced by dislocation slip in non-basal planes (i.e., prismatic planes), which diametrically differs from any other Mg alloys. However, it is noted that deformation twinning still occurs in the polycrystalline UFG Mg-2.5Y occasionally, and a new type of stacking faults (i.e., prismatic stacking faults, PSFs for short) may be present in the vicinity of twins. Feasible mechanisms explaining the formation of PSFs are proposed.
Download or read book Mechanical Response Texture Evolution and Fracture of a Rare earth containing Magnesium Alloy Sheet ZEK100 at Different Strain Rates and Temperatures written by Saadi Habib and published by . This book was released on 2019 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnesium alloys have been at the forefront as possible alternatives to conventional materials such as aluminum and steel for their high specific-strength. However, magnesium alloys exhibit anisotropy, tension-compression asymmetry, and quasi-brittle fracture at ambient temperature, which is exacerbated at high strain rates. It is well known that alloying with rare-earth elements can improve the low uniaxial ductility in comparison with conventional magnesium alloys. Therefore, the mechanical response and texture evolution of a rare-earth-containing magnesium alloy sheet, ZEK100, are investigated under different loading conditions to characterize the anisotropy, tension-compression asymmetry, strain rate sensitivity and thermomechanical response. A reduced-order crystal plasticity model that defines extension twinning, basal a slip, and non-basal slip as the deformation mechanisms, is used to model the experimental results and to give an insight in the active deformation mechanism. In addition, the fracture behavior of ZEK100 is also investigated at different stress states and strain rates. A variety of sample geometries loaded along different processing directions are used to achieve different stress states and deformation mechanisms. Surface strain maps for all the specimens are measured using the digital image correlation (DIC) technique to quantify the strain at fracture. ZEK100 exhibits larger strain at fracture across the gage section of the test specimens aligned with the transverse direction (TD) than specimens aligned with the rolling direction (RD); however, the opposite is shown for the local strain measurements at fracture. Therefore, the crystal plasticity model is used to simulate each loading condition to understand the anisotropic ductile fracture behavior of ZEK100. Using the stress states and deformation mechanisms from the simulations, a novel anisotropic criterion is developed which is an extension of the Hosford-Coulomb (HC) fracture model. The new anisotropic criterion accounts for the role of different deformation mechanisms on the anisotropic fracture response of ZEK100.
Download or read book Mechanical Properties of Fine Grained Magnesium Alloys Processed by Severe Plastic Forging written by Taku Sakai and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnesium 2021 written by Alan Luo and published by Springer Nature. This book was released on 2021-05-28 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: This collection from the 12th International Conference on Magnesium Alloys and Their Applications (Mg 2021)—the longest running conference dedicated to the development of magnesium alloys—covers the breadth of magnesium research and development, from primary production to applications to end-of-life management. Authors from academia, government, and industry discuss new developments in magnesium alloys and share valuable insights. Topics in this volume include but are not limited to the following: Primary production Alloy development Solidification and casting processes Forming and thermo-mechanical processing Other manufacturing process development (including joining and additive manufacturing) Corrosion and protection Modeling and simulation Structural, functional, biomedical, and energy applications Advanced characterization and fundamental theories Recycling and environmental issues
Download or read book Zinc and Its Alloys written by United States. National Bureau of Standards and published by . This book was released on 1931 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanical Properties and Structural Evolution During Deformation of Fine Grain Magnesium and Aluminum Alloys written by Qi Yang and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fundamentals of Magnesium Alloy Metallurgy written by Mihriban O Pekguleryuz and published by Elsevier. This book was released on 2013-03-11 with total page 381 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnesium and magnesium alloys offer a wealth of valuable properties, making them of great interest for use across a wide range of fields. This has led to extensive research focused on understanding the properties of magnesium and how these can be controlled during processing. Fundamentals of magnesium alloy metallurgy presents an authoritative overview of all aspects of magnesium alloy metallurgy, including physical metallurgy, deformation, corrosion and applications.Beginning with an introduction to the primary production of magnesium, the book goes on to discuss physical metallurgy of magnesium and thermodynamic properties of magnesium alloys. Further chapters focus on understanding precipitation processes of magnesium alloys, alloying behaviour of magnesium, and alloy design. The formation, corrosion and surface finishing of magnesium and its alloys are reviewed, before Fundamentals of magnesium alloy metallurgy concludes by exploring applications across a range of fields. Aerospace, automotive and other structural applications of magnesium are considered, followed by magnesium-based metal matrix composites and the use of magnesium in medical applications.With its distinguished editors and international team of expert contributors, Fundamentals of magnesium alloy metallurgy is a comprehensive tool for all those involved in the production and application of magnesium and its alloys, including manufacturers, welders, heat-treatment and coating companies, engineers, metallurgists, researchers, designers and scientists working with these important materials. - Overviews all aspects of magnesium alloy metallurgy - Discusses physical metallurgy of magnesium and thermodynamic properties of magnesium alloys - Reviews the formation, corrosion and surface finishing of magnesium and its alloys
Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2566 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanical Behaviour of Engineering Materials written by Joachim Roesler and published by Springer Science & Business Media. This book was released on 2007-10-16 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: How do engineering materials deform when bearing mechanical loads? To answer this crucial question, the book bridges the gap between continuum mechanics and materials science. The different kinds of material deformation are explained in detail. The book also discusses the physical processes occurring during the deformation of all classes of engineering materials and shows how these materials can be strengthened to meet the design requirements. It provides the knowledge needed in selecting the appropriate engineering material for a certain design problem. This book is both a valuable textbook and a useful reference for graduate students and practising engineers.
Download or read book Materials Design and Manufacturing for Lightweight Vehicles written by P.K. Mallick and published by Elsevier. This book was released on 2010-03-01 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research into the manufacture of lightweight automobiles is driven by the need to reduce fuel consumption to preserve dwindling hydrocarbon resources without compromising other attributes such as safety, performance, recyclability and cost. Materials, design and manufacturing for lightweight vehicles will make it easier for engineers to not only learn about the materials being considered for lightweight automobiles, but also to compare their characteristics and properties.Part one discusses materials for lightweight automotive structures with chapters on advanced steels for lightweight automotive structures, aluminium alloys, magnesium alloys for lightweight powertrains and automotive structures, thermoplastics and thermoplastic matrix composites and thermoset matrix composites for lightweight automotive structures. Part two reviews manufacturing and design of lightweight automotive structures covering topics such as manufacturing processes for light alloys, joining for lightweight vehicles, recycling and lifecycle issues and crashworthiness design for lightweight vehicles.With its distinguished editor and renowned team of contributors, Materials, design and manufacturing for lightweight vehicles is a standard reference for practicing engineers involved in the design and material selection for motor vehicle bodies and components as well as material scientists, environmental scientists, policy makers, car companies and automotive component manufacturers. - Provides a comprehensive analysis of the materials being used for the manufacture of lightweight vehicles whilst comparing characteristics and properties - Examines crashworthiness design issues for lightweight vehicles and further emphasises the development of lightweight vehicles without compromising safety considerations and performance - Explores the manufacturing process for light alloys including metal forming processes for automotive applications
Download or read book Metals Abstracts written by and published by . This book was released on 1998 with total page 1076 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanical Properties of Ceramics written by John B. Wachtman and published by John Wiley & Sons. This book was released on 2009-08-13 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Comprehensive and Self-Contained Treatment of the Theory and Practical Applications of Ceramic Materials When failure occurs in ceramic materials, it is often catastrophic, instantaneous, and total. Now in its Second Edition, this important book arms readers with a thorough and accurate understanding of the causes of these failures and how to design ceramics for failure avoidance. It systematically covers: Stress and strain Types of mechanical behavior Strength of defect-free solids Linear elastic fracture mechanics Measurements of elasticity, strength, and fracture toughness Subcritical crack propagation Toughening mechanisms in ceramics Effects of microstructure on toughness and strength Cyclic fatigue of ceramics Thermal stress and thermal shock in ceramics Fractography Dislocation and plastic deformation in ceramics Creep and superplasticity of ceramics Creep rupture at high temperatures and safe life design Hardness and wear And more While maintaining the first edition's reputation for being an indispensable professional resource, this new edition has been updated with sketches, explanations, figures, tables, summaries, and problem sets to make it more student-friendly as a textbook in undergraduate and graduate courses on the mechanical properties of ceramics.
Download or read book Extrusion of Aluminium Alloys written by T. Sheppard and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years the importance of extruded alloys has increased due to the decline in copper extrusion, increased use in structural applications, environmental impact and reduced energy consumption. There have also been huge technical advances. This text provides comprehensive coverage of the metallurgical, mathematical and practical features of the process.
Download or read book Welding and Joining of Magnesium Alloys written by L Liu and published by Woodhead Publishing. This book was released on 2010-10-28 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the wide application of magnesium alloys in metals manufacturing, it is very important to employ a reliable method of joining these reactive metals together and to other alloys. Welding and joining of magnesium alloys provides a detailed review of both established and new techniques for magnesium alloy welding and their characteristics, limitations and applications. Part one covers general issues in magnesium welding and joining, such as welding materials, metallurgy and the joining of magnesium alloys to other metals such as aluminium and steel. The corrosion and protection of magnesium alloy welds are also discussed. In part two particular welding and joining techniques are reviewed, with chapters covering such topics as inert gas welding, metal inert gas welding and laser welding, as well as soldering, mechanical joining and adhesive bonding. The application of newer techniques to magnesium alloys, such as hybrid laser-arc welding, activating flux tungsten inert gas welding and friction stir, is also discussed. With its distinguished editor and expert team of contributors, Welding and joining of magnesium alloys is a comprehensive reference for producers of primary magnesium and those using magnesium alloys in the welding, automotive and other such industries, as well as academic researchers in metallurgy and materials science.
Download or read book Mechanical Behavior of Materials written by Marc A. Meyers and published by . This book was released on 2008 with total page 856 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes numerous examples and problems for student practice, this textbook is ideal for courses on the mechanical behaviour of materials taught in departments of mechanical engineering and materials science.
