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Functionally Graded Materials

Design, Processing and Applications

herausgegeben von: Prof. Y. Miyamoto, Prof. Dr. W. A. Kaysser, Dr. B. H. Rabin, Prof. A. Kawasaki, Dr. Reneé G. Ford

Verlag: Springer US

Buchreihe : Materials Technology Series

Enthalten in: Professional Book Archive

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Über dieses Buch

Seven years have elapsed since Dr. Renee Ford, editor-in-chief of Materials Technology, first suggested to me to publish a book on Functionally Graded Materials (FGMs). She said that the FGM concept, then largely unknown outside of Japan and a relatively few laboratories elsewhere, would be of great interest to everyone working in the materials field because of its potentially universal applicability. There was no book about FGMs in English at that time, although the number of research papers, review articles, and FGM conference proceedings had been increasing yearly. We discussed what the book should cover, and decided it should present a comprehensive description from basic theory to the most recent applications of FGMs. This would make it useful both as an introduction to FGMs for those simply curious about what this new materials field was all about, and also as a textbook for researchers, engineers, and graduate students in various material fields. The FGM Forum in Japan generously offered to support this publication program. is very difficult for an individual author to write a book that Because it covers such a wide range of various aspects of many different materials, I invited more than 30 eminent materials scientists throughout the world, who were associated with FGM research, to contribute selected topics. I also asked several leading researchers in this field to edit selected chapters: Dr. Barry H. Rabin, then at the U. S.

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Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction

Abstract

In a Functionally Graded Material (FGM) both the composition and the structure gradually change over the volume, resulting in corresponding changes in the properties of the material. The structural unit of an FGM is referred to as an element [1] or a material ingredient [2, 3]. It is a conceptual unit for constructing an FGM that includes various aspects of its chemical composition, physical state, and geometrical configuration. The term, material ingredient, probably expresses the overall concept best. Typical examples are listed in Table 1.1. Material ingredients can resemble biological units such as cells and tissues. For example, bamboo, shell, tooth, and bone all have graded structures consisting of biological material ingredients. Graded structures and functions in nature are discussed in Chapter 2 on Lessons from Nature.

Y. Miyamoto, W. A. Kaysser, B. H. Rabin, A. Kawasaki, Reneé G. Ford

Chapter 2. Lessons from Nature

Abstract

In examining biological load carriers such as the stems of plants and the trunks of trees, animal bones, mollusk shells, and other biological hard tissues, it can be seen that their geometry changes to accommodate to their physical environment. This implies that they are highly adapted to all boundary and loading conditions defined by their environment. Only the most economical construction is able to survive the intense competition for energy as well as the external physical conditions with the minimal amount of materials available to them in their limited living space. For example, the interior structure (architecture) of a bone has an optimized shape with respect to the direction of principal stress and the magnitude of the shear stress [1]. This has been explained to be due to an optimized mechanical design that is characterized by uniform stress distribution with no localized stress peaks [2]. This suggests that both bone and other biological tissues are managed by a self-optimizing system with sensing mechanisms that can detect external mechanical stimuli in order to control the modeling and remodeling of the skeletal system [3]. It can be inferred, therefore, that the shape and ingenious construction of biological hard tissues are the result of a continuous process of intelligent optimization.

Y. Miyamoto, W. A. Kaysser, B. H. Rabin, A. Kawasaki, Reneé G. Ford

Chapter 3. Graded Microstructures

Abstract

It is well known that microstructure plays a predominant role in determining material behavior. Materials engineers therefore seek to control microstructure through processing. Processing studies have traditionally focused on optimizing microstructural characteristics with the intent of producing a uniform microstructure throughout the material. Increasing microstructural uniformity has long been considered a fruitful means of improving properties. In contrast, FGMs are produced containing deliberate spatial nonuniformities in their microstructures. By treating microstructure as a variable that is dependent on position, different material characteristics can be incorporated in a single component. Such a component can be considered a materials system integrated at the microstructural level to achieve optimum performance in a specific application. This is what distinguishes FGMs from other materials.

Y. Miyamoto, W. A. Kaysser, B. H. Rabin, A. Kawasaki, Reneé G. Ford

Chapter 4. Modeling and Design

Abstract

With the advent of powerful computers and robust software, computational modeling has emerged as a very informative and cost effective tool for materials design and analysis. Modeling often can both eliminate costly experiments and provide more information than can be obtained experimentally. Computational modeling has clearly played an important role in FGM research to date, and because of the considerable complexity involved, is expected to play an even greater role in future developments. This chapter introduces some of the common approaches used in modeling FGMs, identifies the major difficulties involved, and, it is hoped, provides useful guidance for future simulation efforts. It focuses mainly on continuum models of the bulk response of FGMs due to thermal or mechanical loading.

Y. Miyamoto, W. A. Kaysser, B. H. Rabin, A. Kawasaki, Reneé G. Ford

Chapter 5. The Characterization of Properties

Abstract

The technology of Functionally Graded Materials (FGMs) enables the realization of innovative and multiple functions that cannot be achieved with conventional homogeneous materials. Predetermined chemical composition profiles (the spatial distribution of their components) as well as predetermined transitions in their microstructure, are intentionally introduced to perform desired functions. Therefore, in order to use FGMs in practical applications, it is important to characterize their properties.

Y. Miyamoto, W. A. Kaysser, B. H. Rabin, A. Kawasaki, Reneé G. Ford

Chapter 6. Processing and Fabrication

Abstract

Since the mid-1980s the processing of FGM materials and structures has become of increasing academic interest. This is reflected in the considerable number of papers that have been published on specific processing routes. During the first Japanese FGM program (1987 to 1991) processing methods were developed for FGM parts to be used as high temperature components of a hypersonic space plane [1, 2, 3]. These early methods included powder metallurgy, physical and chemical vapor deposition, plasma spraying, self-propagating high temperature synthesis (SHS), and galvanoforming (see Figure 6.1). Since 1991, many variations of the initially used methods as well as a considerable number of new processing routes have been developed. Today, the spectrum of processing options ranges from methods already established before FGMs became a well-defined subject, such as processing similar to the case-hardening of steel, to more recently developed methods, such as solid freeform fabrication.

Y. Miyamoto, W. A. Kaysser, B. H. Rabin, A. Kawasaki, Reneé G. Ford

Chapter 7. Applications

Abstract

The FGM concept is applicable to almost all material fields. Examples of a variety of real and potential applications in transport systems, energy conversion systems, cutting tools, machine parts, semiconductors, optics, and biosystems are described in this chapter. Potential applications include those structural and engineering uses that require combinations of incompatible functions such as refractoriness or hardness with toughness, or chemical inertness with toughness. In aerospace and nuclear energy applications, reliability rather than cost is the key issue. But in applications such as cutting tools, high temperature rollers, and engine components, which require wear, heat, mechanical shock, and corrosion resistance; the key issues are the cost/performance ratio and reliability.

Y. Miyamoto, W. A. Kaysser, B. H. Rabin, A. Kawasaki, Reneé G. Ford

Chapter 8. Summary and Outlook

Abstract

Since the first international symposium on FGMs, held in Sendai, Japan in 1990, research and development incorporating this concept has expanded to many different fields worldwide. From the 70 papers at the Sendai Symposium the number has grown to 240 at the 5th symposium held in Dresden, Germany in 1998. The topics covered at this meeting included computer-aided design and modeling; measurement; characterization; fabrication by bulk, layer, melt, preform and other processes; joining; thermal barrier coatings; various applications to cutting tools; heat resistant materials; energy conversion; functional components with graded ferroelectric, magnetic, and optical properties; and biomedical systems. In addition, a number of papers have been published in scientific journals and presented at numerous meetings with FGM sessions.

Y. Miyamoto, W. A. Kaysser, B. H. Rabin, A. Kawasaki, Reneé G. Ford

Backmatter

Titel: Functionally Graded Materials
herausgegeben von: Prof. Y. Miyamoto
Prof. Dr. W. A. Kaysser
Dr. B. H. Rabin
Prof. A. Kawasaki
Dr. Reneé G. Ford
Copyright-Jahr: 1999
Verlag: Springer US
Electronic ISBN: 978-1-4615-5301-4
Print ISBN: 978-0-412-60760-8
DOI: https://doi.org/10.1007/978-1-4615-5301-4