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Friction stir welding (FSW) is a solid state joining process 1,2,3 that uses a rapidly-rotating, non-consumable high strength tool-steel pin that extends from a cylindrical shoulder (Figure 1). The workpieces to be joined are firmly clamped to a worktable; the rotating pin is forced with a pre-determined load into them and moved along the desired bond line. Frictional heating is produced from the rubbing of the rotating shoulder with the workpieces, while the rotating pin deforms (i.e. 'stirs') the locally-heated material. To produce a high integrity defect-free weld, process variables (RPM of the shoulder-pin assembly, traverse speed, the downward forging force) and tool pin design must be chosen carefully. FSW can be considered as a hot-working process in which a large amount of deformation is imparted to the workpiece through the rotating pin and the shoulder. Such deformation gives rise to a weld nugget (whose extent is comparable to the diameter of the pin), a thermomechanically-affected region (TMAZ) and a heat-affected zone (HAZ). Frequently, the weld nugget appears to comprise equiaxed, fine, dynamically recrystallized grains whose size is substantially less than that in the parent material. The objective of the present research was to develop a basic understanding of the evolution of microstructure in the dynamically recrystallized region and to relate it to the deformation process variables of strain, strain rate, and temperature. Such a correlation has not been attempted before perhaps because of the difficulty in quantifying the process variables. To overcome such difficulties, recent work 4 to measure and model the local temperature transients during FSW was utilized, and an approximate method was employed to estimate the strain and strain rate in the weld nugget.
The evolution of mechanical properties and its characterization is important to the weld quality whose further analysis requires mechanical property and microstructure correlation. Present book addresses the basic understanding of the Friction Stir Welding (FSW) process that includes effect of various process parameters on the quality of welded joints. It discusses about various problems related to the welding of dissimilar aluminium alloys including influence of FSW process parameters on the microstructure and mechanical properties of such alloys. As a case study, effect of important process parameters on joint quality of dissimilar aluminium alloys is included.
Friction-stir welding (FSW) is a solid-state joining process primarily used on aluminum, and is also widely used for joining dissimilar metals such as aluminum, magnesium, copper and ferrous alloys. Recently, a friction-stir processing (FSP) technique based on FSW has been used for microstructural modifications, the homogenized and refined microstructure along with the reduced porosity resulting in improved mechanical properties. Advances in friction-stir welding and processing deals with the processes involved in different metals and polymers, including their microstructural and mechanical properties, wear and corrosion behavior, heat flow, and simulation. The book is structured into ten chapters, covering applications of the technology; tool and welding design; material and heat flow; microstructural evolution; mechanical properties; corrosion behavior and wear properties. Later chapters cover mechanical alloying and FSP as a welding and casting repair technique; optimization and simulation of artificial neural networks; and FSW and FSP of polymers. Provides studies of the microstructural, mechanical, corrosion and wear properties of friction-stir welded and processed materials Considers heat generation, heat flow and material flow Covers simulation of FSW/FSP and use of artificial neural network in FSW/FSP
Friction Stir Welding of High Strength 7XXX Aluminum Alloys is the latest edition in the Friction Stir series and summarizes the research and application of friction stir welding to high strength 7XXX series alloys, exploring the past and current developments in the field. Friction stir welding has demonstrated significant benefits in terms of its potential to reduce cost and increase manufacturing efficiency of industrial products in transportation, particularly the aerospace sector. The 7XXX series aluminum alloys are the premium aluminum alloys used in aerospace. These alloys are typically not weldable by fusion techniques and considerable effort has been expended to develop friction stir welding parameters. Research in this area has shown significant benefit in terms of joint efficiency and fatigue performance as a result of friction stir welding. The book summarizes those results and includes discussion of the potential future directions for further optimization. Offers comprehensive coverage of friction stir welding of 7XXX series alloys Discusses the physical metallurgy of the alloys Includes physical metallurgy based guidelines for obtaining high joint efficiency Summarizes the research and application of friction stir welding to high strength 7XXX series alloys, exploring the past and current developments in the field
Friction Stir Welding (FSW) is known to result in a complex microstructural development, with features that remain unexplained, such as: the formation of the onion rings structure. Moreover, various microstructural factors have been suggested to control the strength in Al-Mg AA5xxx welds, without identifying their relative contribution. Furthermore, the influence of the basemetal microstructural parameters (e.g. grains, intermetallic particles, stored energy) on the microstructure-property development has not been previously investigated. These issues are addressed in the present study.
Additive Friction Stir Deposition is a comprehensive summary of the state-of-the-art understanding on this emerging solid-state additive manufacturing technology. Sections cover additive friction stir deposition, encompassing advances in processing science, metallurgical science and innovative applications. The book presents a clear description of underlying physical phenomena, shows how the process determines the printing quality, covers resultant microstructure and properties in the as-printed state, highlights its key capabilities and limitations, and explores niche applications in repair, cladding and multi-material 3D printing. Serving as an educational and research guide, this book aims to provide a holistic picture of additive friction stir deposition-based solid-state additive manufacturing as well as a thorough comparison to conventional beam-based metal additive manufacturing, such as powder bed fusion and directed energy deposition. Provides a clear process description of additive friction stir deposition and highlights key capabilities Summarizes the current research and application of additive friction stir deposition, including material flow, microstructure evolution, repair and dissimilar material cladding Discusses future applications and areas of research for this technology
This book will summarize research work carried out so far on dissimilar metallic material welding using friction stir welding (FSW). Joining of dissimilar alloys and materials are needed in many engineering systems and is considered quite challenging. Research in this area has shown significant benefit in terms of ease of processing, material mixing, and superior mechanical properties such as joint efficiencies. A summary of these results will be discussed along with potential guidelines for designers. Explains solid phase process and distortion of work piece Addresses dimensional stability and repeatability Addresses joint strength Covers metallurgical properties in the joint area Covers fine microstructure Introduces improved materials use (e.g., joining different thicknesses) Covers decreased fuel consumption in light weight aircraft Addresses automotive and ship applications
Friction stir welding (FSW) is a solid-state joining technique that is proven to produce superior joint properties and is particularly helpful in the joining of high-strength aluminum alloys. The historically slower welding speed of FSW (in the range of hundreds of millimeters per minute), among other issues associated with the application of the technique has limited its industrial use to small volume productions. Revolutionary high-speed FSW of aluminum blanks has been developed at Pacific Northwest National Laboratory and satisfactory forming properties were achieved. This work focuses on the characterization of the complex microstructures formed in high-speed FSW butt joints and the correlation between the microstructural features and the mechanical properties of the welds. The effect of increased welding speed was first studied on similar aluminum joints. Materials properties investigated including the tensile strength, fracture toughness, elongation, joint efficiency, microhardness, and corrosion susceptibility. The evolution of the materials properties is found to be related to the welding parameters through the complex physical metallurgy events including materials softening, material mixing and transportation, precipitate reaction, dynamic recrystallization, dynamic recovery, and severe plastic deformation during the friction stir welding process. The formation mechanism was then studied in the joining of dissimilar aluminum alloys AA5182-O and AA6022-T4 with different thicknesses. Local textural analysis and particle analysis aided in the understanding of the material flow patterns and helped in the selection of a fixed location of dissimilar alloys to achieve defect-free joints. The microstructural characterization and analysis methods include transmission electron microscopy, electron diffraction, scanning electron microscopy, optical microscopy, energy-dispersive X-ray spectroscopy, electron backscatter and probability density functions.
This textbook offers a strong introduction to the fundamental concepts of materials science. It conveys the quintessence of this interdisciplinary field, distinguishing it from merely solid-state physics and solid-state chemistry, using metals as model systems to elucidate the relation between microstructure and materials properties. Mittemeijer's Fundamentals of Materials Science provides a consistent treatment of the subject matter with a special focus on the microstructure-property relationship. Richly illustrated and thoroughly referenced, it is the ideal adoption for an entire undergraduate, and even graduate, course of study in materials science and engineering. It delivers a solid background against which more specialized texts can be studied, covering the necessary breadth of key topics such as crystallography, structure defects, phase equilibria and transformations, diffusion and kinetics, and mechanical properties. The success of the first edition has led to this updated and extended second edition, featuring detailed discussion of electron microscopy, supermicroscopy and diffraction methods, an extended treatment of diffusion in solids, and a separate chapter on phase transformation kinetics. “In a lucid and masterly manner, the ways in which the microstructure can affect a host of basic phenomena in metals are described.... By consistently staying with the postulated topic of the microstructure - property relationship, this book occupies a singular position within the broad spectrum of comparable materials science literature .... it will also be of permanent value as a reference book for background refreshing, not least because of its unique annotated intermezzi; an ambitious, remarkable work.” G. Petzow in International Journal of Materials Research. “The biggest strength of the book is the discussion of the structure-property relationships, which the author has accomplished admirably.... In a nutshell, the book should not be looked at as a quick ‘cook book’ type text, but as a serious, critical treatise for some significant time to come.” G.S. Upadhyaya in Science of Sintering. “The role of lattice defects in deformation processes is clearly illustrated using excellent diagrams . Included are many footnotes, ‘Intermezzos’, ‘Epilogues’ and asides within the text from the author’s experience. This ..... soon becomes valued for the interesting insights into the subject and shows the human side of its history. Overall this book provides a refreshing treatment of this important subject and should prove a useful addition to the existing text books available to undergraduate and graduate students and researchers in the field of materials science.” M. Davies in Materials World.
A single source of information on the fundamental concepts and latest research applications of friction stir welding and processing Friction Stir Welding and Processing: Fundamentals to Advancements provides concise yet comprehensive coverage of the field of friction stir welding, with an eye toward future research directions and applications. Throughout the book, case studies provide real-world context and highlight applications for various engineering sectors. With contributions from an array of leaders in the field, Friction Stir Welding and Processing provides readers with a single source of information on all aspects of FSW and FSP. After explaining the fundamentals of friction stir welding (FSW) and its variants, the book discusses composite fabrication techniques using friction stir processing (FSP). Different types of friction techniques are covered, as is the equipment used. Detailed characterization of samples and composites are included. Additional topics discussed include the impact of FSW on the economics of production, methods for coupling FSW/FSP with additive manufacturing, composite fabrication, and process-property relationships. Master the basic concepts of friction stir welding and its variants Discover the role of FSW in developing hybrid manufacturing techniques Follow case studies that connect theoretical concepts to real-world experimental results Learn from contributions from an array of global thought leaders in the field This is a valuable compendium on the topic for engineers and designers who utilize welding and advanced manufacturing across industries, as well as graduate students and post-graduate researchers who are exploring new friction stir welding applications.