Download or read book Effect of Twinning on Texture and Strain Hardening in Magnesium Alloys Subjected to Different Strain Paths written by Lan Jiang and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The evolution of flow stress and microstructure during the deformation of two Mg-based (+Al, Mn, Zn) alloys has been studied under various conditions of temperature and strain rate. The tested materials were taken from AZ31 and AM30 extruded tubes. The effect of twinning was investigated by using uniaxial tension, uniaxial compression and ring hoop tension testing. Strain path change testing, i.e. tensile prestraining followed by uniaxial compression, was carried out to study the role of contraction and double twins on the subsequent deformation. Optical metallography and EBSD techniques were employed to study the microstructural development. The first part of the investigation focused on the flow stresses developed during deformation along the three different strain paths. It was found that at low temperatures (≤200°C), the flow behaviors are mainly controlled by twinning. At temperatures above 200°C but below 350°C, especially at a strain rate of 0.001s-1, the deformation is largely accommodated in partially dynamically recrystallized regions. As a result, the formation of voids in these regions causes premature fracture. The second part focused on the twinning behavior displayed during deformation to a strain of 0.15. The results indicate that the initial extrusion texture plays an important role in the formation of different types of twins and that the twinning behavior also depends on the strain path. {10-11} contraction and {10-11}-{10-12} double twinning are the dominant twinning mechanisms in uniaxial tension, while {10-12} extension twinning prevails in uniaxial compression and ring hoop tension testing. Grain size, temperature, strain and strain rate all have significant effects on the volume fraction of contraction and double twins. There is a sigmoidal relationship between the volume fraction of extension twins and the strain. The effect of grain size (in this grain size range) on the volume fraction of extension twins is small. For a given strain, at high strain rates, temperature does not have much influence on the volume fraction (below 200°C). In the third part of the investigation, the deformation texture associated with twinning was examined. The near 100% volume fraction of {10-12} extension twins gives rise to significant texture changes. By contrast, {10-11} contraction and {10-11}-{10-12} double twinning only make a small contribution to texture change due to the limited volume fraction of twinned material. Schmid factor analysis indicates that, for the {10-12} extension twins, all variants that are favorably oriented (i.e. with the highest SF values) can undergo rapid and complete twinning. For the {10-11} contraction twins, only variants in the TD component (11-20) 10-10 follow the SF criterion. The development of internal stresses, which somehow particularly affect the RD component (10-10) 0001 grains, may explain this difference. In the final part of the investigation, the effects of twinning on the strain hardening behavior and on ductility were studied. Different behaviors are shown to be responsible for the sharply contrasting strain hardening characteristics of the experimental flow curves. When a certain volume fraction (≥20% in the present study) is reached, contraction and double twinning generate net softening effects. Nevertheless, when they interact with extension twins, the hardening effect may predominate. On the other hand, extension twinning generally introduces a hardening effect. The hardening effect due to twin boundaries appears to be stronger than that from the volume fraction of extension twins, since the hardening associated with extension twinning cannot be explained by the volume fraction alone. Depending on the deformation conditions, twinning can be detrimental to the formability on the one hand but it can also be beneficial on the other."--

Download or read book Magnesium Alloys written by Frank Czerwinski and published by BoD – Books on Demand. This book was released on 2011-01-14 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scientists and engineers for decades searched to utilize magnesium, known of its low density, for light-weighting in many industrial sectors. This book provides a broad review of recent global developments in theory and practice of modern magnesium alloys. It covers fundamental aspects of alloy strengthening, recrystallization, details of microstructure and a unique role of grain refinement. The theory is linked with elements of alloy design and specific properties, including fatigue and creep resistance. Also technologies of alloy formation and processing, such as sheet rolling, semi-solid forming, welding and joining are considered. An opportunity of creation the metal matrix composite based on magnesium matrix is described along with carbon nanotubes as an effective reinforcement. A mixture of science and technology makes this book very useful for professionals from academia and industry.

Download or read book The Role of Deformation Twinning on Strain Hardening and Recrystallization in Magnesium Alloy AZ31 written by Amanda J. Levinson and published by . This book was released on 2012 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: The quasi-static mechanical response of annealed, highly textured AZ31 rolled plate was measured in simple compression on two sample directions, each promoting a different twin family. A high plastic anisotropy with extreme strain hardening in both directions was observed. New insights on the influence of both twin types to this behavior were derived by correlating changes in the strain hardening rates with the microstructure evolution. Extension twins nucleated at low strains, grew to consume most of the structure, and saturated at strains below the peak hardening rates. Thin contraction twins were initially postulated to be responsible for the peak hardening rates by limiting the hard pyramidal c+a slip length (producing a Hall-Petch type strengthening). However, subsequent experimental investigations raised questions on whether these are not present at the spacing required to account for the peak hardening rate. Thus, neither twin family was deemed responsible for the peak strain hardening rates. The effect of grain size on deformation twinning during strain hardening was also investigated by producing a similarly textured AZ31 plate with a larger grain size. A lower twinning stress was confirmed in this material. An additional change in strain hardening rate was associated with the nucleation of secondary extension twins forming perpendicular to the primary twin, limiting the growth potential of the pre-existing twins. The microstructure evolution during isothermal static annealing was investigated to critically evaluate the contributions of extension and contraction twins to the recrystallized microstructure after room temperature deformation, and establish the potential of these twins to alter the recrystallized texture. Contraction twins were potent sites for recrystallized nuclei producing many favorably oriented orientations for reduction of the strong c-axis fiber texture; while extension twins were not very effective in recrystallization. Recovery before the onset of recrystallization was extensive when the c-axis in most grains was compressed. Incomplete recrystallization within the hardest grains was deemed responsible for the retention of the c-axis fiber texture. These new insights were employed to identify the benefits of laser-roller hemming versus conventional hemming. Hemming is an automotive processing operation used to join inner and outer body panels involving severe forming and design requirements.

Download or read book Magnesium Technology 2013 written by Norbert Hort and published by Springer. This book was released on 2016-12-09 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Magnesium Technology Symposium, the event on which this volume is based, is one of the largest yearly gatherings of magnesium experts in the world. Papers reflect all aspects of the field including primary production to applications, recycling, basic research findings, and industrialization. Readers will find broad coverage of current topics, including alloys and their properties, cast products and processing, wrought products and processing, corrosion and surface finishing, ecology, and more. New and emerging applications in such areas as hydrogen storage are also examined.

Download or read book Magnesium Technology 2011 written by Wim Sillekens and published by Springer. This book was released on 2016-12-10 with total page 599 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Magnesium Technology Symposium, which takes place every year at the TMS Annual Meeting & Exhibition, is one of the largest yearly gatherings of magnesium specialists in the world. Papers are presented in all aspects of the field, ranging from primary production to applications to recycling. Moreover, papers explore everything from basic research findings to industrialization. Magnesium Technology 2011 covers a broad spectrum of current topics, including alloys and their properties; cast products and processing; wrought products and processing; forming, joining, and machining; corrosion and surface finishing; ecology; and structural applications. In addition, you'll find coverage of new and emerging applications in such areas as biomedicine and hydrogen storage.

Download or read book Comprehensive Materials Processing written by and published by Newnes. This book was released on 2014-04-07 with total page 5485 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive Materials Processing, Thirteen Volume Set provides students and professionals with a one-stop resource consolidating and enhancing the literature of the materials processing and manufacturing universe. It provides authoritative analysis of all processes, technologies, and techniques for converting industrial materials from a raw state into finished parts or products. Assisting scientists and engineers in the selection, design, and use of materials, whether in the lab or in industry, it matches the adaptive complexity of emergent materials and processing technologies. Extensive traditional article-level academic discussion of core theories and applications is supplemented by applied case studies and advanced multimedia features. Coverage encompasses the general categories of solidification, powder, deposition, and deformation processing, and includes discussion on plant and tool design, analysis and characterization of processing techniques, high-temperatures studies, and the influence of process scale on component characteristics and behavior. Authored and reviewed by world-class academic and industrial specialists in each subject field Practical tools such as integrated case studies, user-defined process schemata, and multimedia modeling and functionality Maximizes research efficiency by collating the most important and established information in one place with integrated applets linking to relevant outside sources

Download or read book Advances in Wrought Magnesium Alloys written by Colleen Bettles and published by Elsevier. This book was released on 2012-04-25 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: This important book summarises the wealth of recent research on our understanding of process-property relationships in wrought magnesium alloys and the way this understanding can be used to develop a new generation of alloys for high-performance applications. After an introductory overview of current developments in wrought magnesium alloys, part one reviews fundamental aspects of deformation behaviour. These chapters are the building blocks for the optimisation of processing steps covered in part two, which discusses casting, extrusion, rolling and forging technologies. The concluding chapters cover applications of wrought magnesium alloys in automotive and biomedical engineering. With its distinguished editors, and drawing on the work of leading experts in the field, Advances in wrought magnesium alloys is a standard reference for those researching, manufacturing and using these alloys. Summarises recent research on our understanding of process-property relationships in wrought magnesium alloys Discusses the way this understanding can be used to develop a new generation of alloys for high-performance applications Reviews casting, extrusion, rolling and forging technologies, fundamental aspects of deformation behaviour, and applications of wrought magnesium alloys in automotive and biomedical engineering

Download or read book Forming the Future written by Glenn Daehn and published by Springer Nature. This book was released on 2021-07-10 with total page 2890 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this collection, scientists and engineers from across industry, academia, and government present their latest improvements and innovations in all aspects of metal forming science and technology, with the intent of facilitating linkages and collaborations among these groups. Chapters cover the breadth of metal forming topics, from fundamental science to industrial application.

Download or read book Magnesium Technology 2017 written by Kiran N. Solanki and published by Springer. This book was released on 2017-02-14 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Magnesium Technology Symposium, the event on which this collection is based, is one of the largest yearly gatherings of magnesium specialists in the world. Papers represent all aspects of the field, ranging from primary production to applications to recycling. Moreover, papers explore everything from basic research findings to industrialization. Magnesium Technology 2017 covers a broad spectrum of current topics, including alloys and their properties; cast products and processing; wrought products and processing; forming, joining, and machining; corrosion and surface finishing; ecology; and structural applications. In addition, there is coverage of new and emerging applications.

Download or read book Magnesium Technology 2019 written by Vineet V. Joshi and published by Springer. This book was released on 2019-02-14 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Magnesium Technology Symposium, the event on which this collection is based, is one of the largest yearly gatherings of magnesium specialists in the world. Papers represent all aspects of the field, ranging from primary production to applications to recycling. Moreover, papers explore everything from basic research findings to industrialization. Magnesium Technology 2019 covers a broad spectrum of current topics, including alloys and their properties; cast products and processing; wrought products and processing; forming, joining, and machining; corrosion and surface finishing; and structural applications. In addition, there is coverage of new and emerging applications.

Download or read book Influence of Microstructural Length Scale on Deformation Behavior of Magnesium Alloys written by Wei Yuan and published by . This book was released on 2012 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Friction stir processing (FSP) is emerging as an effective tool for microstructural modification. Mg-Al-Zn alloys with different aluminum contents were subjected to FSP to achieve fine grained and ultrafine grained (UFG) structure. The objective of this work was to study the influence of microstructural length scale on the governing deformation and strengthening mechanisms of FSP magnesium alloys. FSP introduced strong basal fiber texture and processing parameter dependent grain/precipitate size and distribution. Grain refinement promoted non-basal dislocation activation at room temperature. The strength of the alloy increased as a consequence of grain refinement following classic Hall-Petch relationship to different extents due to texture effect. Remarkable difference in tensile behavior was observed when the dominant deformation mode changed from basal to non-basal slip for various grain sizes. Specimens which deformed mainly by basal slip exhibited low tensile strength, high degree of work hardening and fractured before developing a neck. However, specimens which deformed by non-basal slip showed high strength, low degree of work hardening and a large fraction of post-uniform strain as a result of increased strain rate sensitivity. A high ductility of ~65% in FSP magnesium was attributed to extensive basal dislocation slip with the additional work hardening from activation of extension twin. Grain refinement reduced the uniform strain significantly, especially for UFG magnesium due to the low work hardening rate and high rate of dislocation recovery. High strength magnesium alloy with ~435 MPa in tensile strength and~23% in ductility was achieved. The promising combination of strength and ductility was attributed to the UFG structure with low dislocation density and fine [Beta]-phase precipitates"--Abstract, leaf iv.

Download or read book Modeling the Role of Deformation Twinning in Mg Alloy Az31b written by Ashutosh Jain and published by LAP Lambert Academic Publishing. This book was released on 2010-11 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: The role of twinning in the anisotropic behavior and ductility of magnesium alloys is analyzed at ambient as well as elevated temperatures. Magnesium alloy AZ31B sheet is investigated as a model system, because it is the most common wrought magnesium alloy. Uniaxial compression tests are conducted at room temperature and at elevated temperatures to measure the anisotropy of the strength and strain at various strain levels.A viscoplastic self-consistent polycrystal modeling approach was used to model the deformation behavior; including the anisotropy and texture evolution. Temperature dependence of parameters affecting activity of different deformation modes, such as Critical Resolved Shear Stress (CRSS) and strain hardening, and the volume fraction of twinned grains are investigated with the help of the polycrystal plasticity model.The model, thus developed, could find application for predicting material s response in complex loading conditions.

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 Mechanisms of Hardening in HCP Structures Through Dislocation Transmutation and Accommodation Effects by Glide Twinning written by Andrew Lars Oppedal and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: At low temperatures, glide twinning activates in HCP structures easier than non-close packed slip necessary to accommodate strain along the c-axis. In contrast to slip, twinning occurs as an accumulation of successive stacking faults that properly report reconstruction of the stacking sequence in a new crystal-reorientated lenticular lamella. These faults are spread by partial dislocations known as twinning dislocations, forcing atoms to switch positions by shear into new crystal planes. As the twinning dislocations thread the faults, the new crystal lamella grows at the expense of the parent. Grain texture changes upon strain, and a strong non-linear trend marks the strain hardening rate. The strain hardening rate changes to a point where it switches sign upon strain. Since activation of these twinning dislocations obey Schmid's law, twinning could be precluded or exhaustively promoted in sharp textures upon slight changes in loading orientations, so strong anisotropy arises. Moreover, a twinning shear can only reproduce the stacking sequence in one direction, unless the twin mode changes or the c/a ratio crosses a certain ratio. When a twin mode arises with reversed sign, the reorientation is different and more importantly, the strength is different and also the growth rate. Therefore, in addition to strain anisotropy, twin polarity induces a strong asymmetry in textured HCP structures, e.g. wrought HCP metals. This anisotropy/asymmetry is still a barrier to the great economic gain expected from the industrialization of low density, high specific strength and stiffness, HCP Magnesium. This barrier has stimulated efforts to identify the missing links in current scientific knowledge to proper prediction of Magnesium anisotropy. The effect of twinninginduced texture change on the mechanical response is of a major concern. Mesoscale modelers still struggle, without success to predict simultaneously twinning and strain hardening rates upon arbitrary loading directions. We propose a new mechanism that relies on admitting dislocation populations of the twin by dislocations transmuted from the parent when they intersect twinning disconnections. These dislocations interact with original dislocations created in the twin to cause hardening able to faithfully capture anisotropy upon any loading orientation and any initial texture.

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 Metals Abstracts Index written by and published by . This book was released on 1996 with total page 1622 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Light Metals 2017 written by Arne P. Ratvik and published by Springer. This book was released on 2017-02-10 with total page 1385 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Light Metals symposia at the TMS Annual Meeting & Exhibition present the most recent developments, discoveries, and practices in primary aluminum science and technology. The annual Light Metals volume has become the definitive reference in the field of aluminum production and related light metal technologies. The 2017 collection includes papers from the following symposia:Alumina and BauxiteAluminum Alloys, Processing, and CharacterizationAluminum Reduction TechnologyCast Shop TechnologyCast Shop Technology: Recycling and Sustainability Joint SessionElectrode TechnologyThe Science of Melt Refining: An LMD Symposium in Honor of Christian Simensen and Thorvald Abel Engh