Plates of continuously cast AA5083 were subjected to friction stir processing (FSP) by three overlapping plunge and traverses. The FSP used a threaded pin tool with a pin diameter of 3 mm, pin length of 3 mm and a shoulder diameter of 10 mm. The process was run at constant tool rotation and traverse speeds of 800 rpm and 76.2 mm min-1, respectively. The microstructure of the processed region was examined by optical microscopy and orientation imaging microscopy. FSP of the AA5083 reduced the average grain size from approximately 60 um in the base metal to 3-4 um in the processed zone. In addition, it created a homogeneous microstructure and, in particular, a refined and homogenous particle distribution without damage to the particles. Large tensile samples with gage sections of 1x3x8 mm were prepared by wire EDM for high-temperature tension testing. Tensile tests were carried out at 450 degrees C under different strain rates. The relationship between strain rate and elongation was established. A maximum superplastic elongation of ~550% was obtained at a strain rate of 3 x 10-3 s-1. The formation mechanism of refined grain structure and the superplastic characteristic of FSP material will be discussed in this paper.

Friction stir welding has seen significant growth in both technology implementation and scientific exploration. This book covers all aspects of friction stir welding and processing, from fundamentals to design and applications. It also includes an update on the current research issues in the field of friction stir welding and a guide for further research.

This book covers the rapidly growing area of friction stir welding. It also addresses the use of the technology for other types of materials processing, including superplastic forming, casting modification, and surface treatments. The book has been prepared to serve as the first general reference on friction stir technology,. Information is provided on tools, machines, process modeling, material flow, microstructural development and properties. Materials addressed include aluminum alloys, titanium alloys, steels, nickel-base alloys, and copper alloys. The chapters have been written by the leading experts in this field, representing leading industrial companies and university and government research insititutions.

Here is a comprehensive resource that compiles extensive descriptions of friction stir processing, fabrication of surface metal matrix composites, and friction surfacing into one volume. The book is separated into four sections, beginning with a discussion of surface tailoring of metals by friction stir processing. This first section delves into the basics of friction stir processing (FSP), incorporating illustrations to explain the supporting mechanisms of this process. This section culminates with the introduction of potential applications of FSP in the manufacturing industry and obstacles that may arise when implemented. The following two sections explore and discuss surface metal matrix composites by friction stir processing and surface engineering by friction surfacing. They provide a thorough explanation of the material systems involved in the respective processes and discuss in detail the mechanisms behind each. The book, which closes with a comprehensive discussion of recent developments in friction-assisted processes and their functionality, offers a unique compilation of information on these increasingly prominent developments in the field of surface engineering. This volume organizes the information in a manner that is both easily accessible and comprehensible, utilizing visuals such as figures, tables, and photographs to enhance readers’ understanding. Key features: • Explores a multitude of topics within the field of surface engineering at length • Summarizes and explores the mechanical foundation of friction stir processing, fabrication of surface metal matrix composites, and friction surfacing • Incorporates figures and tables to aid in illustrating the concepts discussed • Offers potential applications and discusses future benefits of specific elements pertaining to surface engineering

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.

Abstract: Friction stir processing (FSP), a solid-state post-processing technique that can provide localized modification and control of microstructures in near-surface layers of metallic components is developed based on the principles of friction stir welding (FSW). In this study, FSP was carried out in two phases. In Phase I, FSP was applied to one inch thick, sand casting A206 aluminum and 0.25 inch A367 bending fatigue sample. Optical microscope, SEM and EDS measurements have been performed to reveal a homogenous microstructure in the stirred zone, in which the porosities were quantitatively reduced, the second phase particles have been broken up and distributed in the Al matrix and there were some new components generated. Thermocouples have been applied to acquire the temperature gradient and thermo history during FSP. A range of material properties, including hardness and tensile measurement in A206, and bending fatigue test in A367 were examined. FSP resulted in an increase in hardness of the nugget compared to the hardness profile of the T4 condition. A significant improvement of the ductility of A206 was found after FSP compared to the ductility of T4 A206, but the FSP process slightly reduced the strength of A206. In Phase II, FSP was used for composite fabrication in the top layer of A206 substrate. The discontinuously reinforced aluminum (DRA) which contained 15% weight percent SiC was introduced into one inch thick sand cast A206 substrate. The surface composite layer is well bonded to the aluminum alloy substrate. Defects were not visible validating that FSP is an effective way for composite fabrication in Al cast alloys.

Metal Matrix Composites by Friction Stir Processing discusses the capabilities of utilizing friction stir processing (FSP) as a tool to manufacture new materials, such as composites. FSP is considered a tool for grain refinement. However, this work illustrates how FSP has a wider capability due to the material flow and mixing the process offers. This book highlights such aspects by demonstrating the ability of the process to incorporate a second phase and make metal matrix composites (MMCs). The book covers the current research on processing MMCs by FSP, and presents a novel approach of making ductile MMCs by FSP using metal particle reinforcements. Demonstrates how friction stir processing can be used to make metal matrix composites Includes a review of different approaches of making metal matrix composites by friction stir processing Demonstrates the utility of friction stir processing in making new types of non-equilibrium ductile composites Provides a comparison of properties of friction stir processed composites to those of conventional metal matrix composites