《材料科学导论 Introduction to Materials Science》参考书籍：Materials Science and Engineering - An Introduction（7th）

496Tc0101-1412/20/057:11page1 2nd REVISE PagES EQA Chapter 1 Introduction eaal egeas A familiar item that is fabricated from three different material types is the beverage container. Beverages are marketed in aluminum(metal)cans(top), glass( cerami bottles(center), and plastic(polymer)bottles(bottom).(Permission to use these photographs was granted by the Coca-Cola Company. Coca-Cola, Coca-Cola Classic, the Contour Bottle design and the Dynamic Ribbon are registered trademarks of The Coca-Cola Company and used with its express permission.)

• 1 Afamiliar item that is fabricated from three different material types is the beverage container. Beverages are marketed in aluminum (metal) cans (top), glass (ceramic) bottles (center), and plastic (polymer) bottles (bottom). (Permission to use these photographs was granted by the Coca-Cola Company. Coca-Cola, Coca-Cola Classic, the Contour Bottle design and the Dynamic Ribbon are registered trademarks of The Coca-Cola Company and used with its express permission.) Chapter 1 Introduction 1496T_c01_01-14 12/20/05 7:11 Page 1 2nd REVISE PAGES

496Tc0101-1412/20/057:11page2 2nd REVISE PaGES EQA Learning Objectives After careful study of this chapter you should be able to do the following: 1. List six different property classifications of 4.(a) List the three primary classifications of solid materials that determine their applicability. materials, and then cite the distinctive 2. Cite the four components that are involved in chemical feature of each the design, production, and utilization of (b)Note the two types of advanced materials materials, and briefly describe the interrelation and, for each, its distinctive feature s) ships between these components. 5.(a) Briefly define"smart material/system. 3. Cite three criteria that nportant in the ma- (b)Briefly explain the concept of"nanotech terials selection process nology"as it applies to materials 1.1 HISTORICAL PERSPECTIVE Materials are probably more deep-seated in our culture than most of us realize. Transportation, housing, clothing, communication, recreation, and food production- virtually every segment of our everyday lives is influenced to one degree or another by materials. Historically, the development and advancement of societies have been intimately tied to the members ability to produce and manipulate materials to fill their needs. In fact, early civilizations have been designated by the level of their materials development(Stone Age, Bronze Age, Iron Age) The earliest humans had access to only a very limited number of materials, those that occur naturally: stone, wood, clay, skins, and so on. With time they dis- covered techniques for producing materials that had properties superior to those of the natural ones; these new materials included pottery and various metals. Fur thermore, it was discovered that the properties of a material could be altered by heat treatments and by the addition of other substances. At this point, materials uti- lization was totally a selection process that involved deciding from a given, rather limited set of materials the one best suited for an application by virtue of its char acteristics. It was not until relatively recent times that scientists came to understand the relationships between the structural elements of materials and their properties. This knowledge, acquired over approximately the past 100 years, has empowered them to fashion, to a large degree, the characteristics of materials. Thus, tens of thou sands of different materials have evolved with rather specialized characteristics that meet the needs of our modern and complex society; these include metals, plastics, glasses, and fibers. The development of many technologies that make our existence so comfort able has been intimately associated with the accessibility of suitable materials. An advancement in the understanding of a material type is often the forerun ner to the stepwise progression of a technology. For example, automobiles would not have been possible without the availability of inexpensive steel or some other comparable substitute In our contemporary era, sophisticated elec- tronic devices rely on components that are made from what are called semicon ducting materials The approximate dates for the beginnings of Stone, Bronze, and Iron Ages were 2.5 BC,3500 BC and 1000 BC, respectively

1.1 HISTORICAL PERSPECTIVE Materials are probably more deep-seated in our culture than most of us realize. Transportation, housing, clothing, communication, recreation, and food production— virtually every segment of our everyday lives is influenced to one degree or another by materials. Historically, the development and advancement of societies have been intimately tied to the members’ ability to produce and manipulate materials to fill their needs. In fact, early civilizations have been designated by the level of their materials development (Stone Age, Bronze Age, Iron Age).1 The earliest humans had access to only a very limited number of materials, those that occur naturally: stone, wood, clay, skins, and so on. With time they dis￾covered techniques for producing materials that had properties superior to those of the natural ones; these new materials included pottery and various metals. Fur￾thermore, it was discovered that the properties of a material could be altered by heat treatments and by the addition of other substances. At this point, materials uti￾lization was totally a selection process that involved deciding from a given, rather limited set of materials the one best suited for an application by virtue of its char￾acteristics. It was not until relatively recent times that scientists came to understand the relationships between the structural elements of materials and their properties. This knowledge, acquired over approximately the past 100 years, has empowered them to fashion, to a large degree, the characteristics of materials.Thus, tens of thou￾sands of different materials have evolved with rather specialized characteristics that meet the needs of our modern and complex society; these include metals, plastics, glasses, and fibers. The development of many technologies that make our existence so comfort￾able has been intimately associated with the accessibility of suitable materials. An advancement in the understanding of a material type is often the forerun￾ner to the stepwise progression of a technology. For example, automobiles would not have been possible without the availability of inexpensive steel or some other comparable substitute. In our contemporary era, sophisticated elec￾tronic devices rely on components that are made from what are called semicon￾ducting materials. Learning Objectives After careful study of this chapter you should be able to do the following: 1. List six different property classifications of materials that determine their applicability. 2. Cite the four components that are involved in the design, production, and utilization of materials, and briefly describe the interrelation￾ships between these components. 3. Cite three criteria that are important in the ma￾terials selection process. 4. (a) List the three primary classifications of solid materials, and then cite the distinctive chemical feature of each. (b) Note the two types of advanced materials and, for each, its distinctive feature(s). 5. (a) Briefly define “smart material/system.” (b) Briefly explain the concept of “nanotech￾nology” as it applies to materials. 1 The approximate dates for the beginnings of Stone, Bronze, and Iron Ages were 2.5 million BC, 3500 BC and 1000 BC, respectively. 1496T_c01_01-14 12/20/05 7:11 Page 2 2nd REVISE PAGES

496Tc0101-1411/9/0517:02Page3 REVISED PAGES EQA 1.2 Materials Science and Engineering.3 1.2 MATERIALS SCIENCE AND ENGINEERING Sometimes it is useful to subdivide the discipline of materials science and engi- neering into materials science and materials engineering subdisciplines. Strictly speaking,""materials science"involves investigating the relationships that exist between the structures and properties of materials. In contrast, " materials engi- neering"is, on the basis of these structure-property correlations, designing or en- gineering the structure of a material to produce a predetermined set of properties. From a functional perspective, the role of a materials scientist is to develop or syn- hesize new materials, whereas a materials engineer is called upon to create new products or systems using existing materials, and/or to develop techniques for pro- cessing materials. Most graduates in materials programs are trained to be both materials scientists and materials engineers. Structure"is at this point a nebulous term that deserves some explanation. In interactions with their nuclei. On an atomic level, structure encompasses the e brief, the structure of a material usually relates to the arrangement of its internal components. Subatomic structure involves electrons within the individual atoms and ganization of atoms or molecules relative to one another. The next larger structural realm, which contains large groups of atoms that are normally agglomerated to- gether, is termed"microscopic, " meaning that which is subject to direct observation using some type of microscope. Finally, structural elements that may be viewed with the naked eye are termed"macroscopic. The notion of"property"deserves elaboration. While in service use, all mate rials are exposed to external stimuli that evoke some type of response For exam ple, a specimen subjected to forces will experience deformation, or a polished metal surface will reflect light. A property is a material trait in terms of the kind and mag nitude of response to a specific imposed stimulus. Generally, definitions of proper- ties are made independent of material shape and size. Virtually all important properties of solid materials may be grouped into six dif- ent categories: mechanical, electrical, thermal, magnetic, optical, and deteriorative For each there is a characteristic type of stimulus capable of provoking different re- sponses. Mechanical properties relate deformation to an applied load or force; exam ples include elastic modulus and strength. For electrical properties, such as electrical conductivity and dielectric constant, the stimulus is an electric field. The thermal be- havior of solids can be represented in terms of heat capacity and thermal conductiv ity. Magnetic properties demonstrate the response of a material to the application of magnetic field. For optical properties, the stimulus is electromagnetic or light radia- tion; index of refraction and reflectivity are representative optical properties. Finally, deteriorative characteristics relate to the chemical reactivity of materials. The chapters that follow discuss properties that fall within each of these six classifications. In addition to structure and properties, two other important components are involved in the science and engineering of materials-namely, "processing"and "performance. "With regard to the relationships of these four components, the struc- ture of a material will depend on how it is processed. Furthermore, a materials per- formance will be a function of its properties. Thus, the interrelationship between processing, structure, properties, and performance is as depicted in the schematic illustration shown in Figure 1.1. Throughout this text we draw attention to the 2 Throughout this text we draw attention to the relationships between material properties and structural elements

1.2 Materials Science and Engineering • 3 2 Throughout this text we draw attention to the relationships between material properties and structural elements. 1.2 MATERIALS SCIENCE AND ENGINEERING Sometimes it is useful to subdivide the discipline of materials science and engi￾neering into materials science and materials engineering subdisciplines. Strictly speaking, “materials science” involves investigating the relationships that exist between the structures and properties of materials. In contrast, “materials engi￾neering” is, on the basis of these structure–property correlations, designing or en￾gineering the structure of a material to produce a predetermined set of properties.2 From a functional perspective, the role of a materials scientist is to develop or syn￾thesize new materials, whereas a materials engineer is called upon to create new products or systems using existing materials, and/or to develop techniques for pro￾cessing materials. Most graduates in materials programs are trained to be both materials scientists and materials engineers. “Structure” is at this point a nebulous term that deserves some explanation. In brief, the structure of a material usually relates to the arrangement of its internal components. Subatomic structure involves electrons within the individual atoms and interactions with their nuclei. On an atomic level, structure encompasses the or￾ganization of atoms or molecules relative to one another. The next larger structural realm, which contains large groups of atoms that are normally agglomerated to￾gether, is termed “microscopic,” meaning that which is subject to direct observation using some type of microscope. Finally, structural elements that may be viewed with the naked eye are termed “macroscopic.” The notion of “property” deserves elaboration. While in service use, all mate￾rials are exposed to external stimuli that evoke some type of response. For exam￾ple, a specimen subjected to forces will experience deformation, or a polished metal surface will reflect light. A property is a material trait in terms of the kind and mag￾nitude of response to a specific imposed stimulus. Generally, definitions of proper￾ties are made independent of material shape and size. Virtually all important properties of solid materials may be grouped into six dif￾ferent categories: mechanical, electrical, thermal, magnetic, optical, and deteriorative. For each there is a characteristic type of stimulus capable of provoking different re￾sponses. Mechanical properties relate deformation to an applied load or force; exam￾ples include elastic modulus and strength. For electrical properties, such as electrical conductivity and dielectric constant, the stimulus is an electric field. The thermal be￾havior of solids can be represented in terms of heat capacity and thermal conductiv￾ity. Magnetic properties demonstrate the response of a material to the application of a magnetic field. For optical properties, the stimulus is electromagnetic or light radia￾tion; index of refraction and reflectivity are representative optical properties. Finally, deteriorative characteristics relate to the chemical reactivity of materials.The chapters that follow discuss properties that fall within each of these six classifications. In addition to structure and properties, two other important components are involved in the science and engineering of materials—namely, “processing” and “performance.”With regard to the relationships of these four components, the struc￾ture of a material will depend on how it is processed. Furthermore, a material’s per￾formance will be a function of its properties. Thus, the interrelationship between processing, structure, properties, and performance is as depicted in the schematic illustration shown in Figure 1.1. Throughout this text we draw attention to the 1496T_c01_01-14 11/9/05 17:02 Page 3 REVISED PAGES

496Tc0101-1412/20/057:11page4 2nd REVISE Pages EQA 4. Chapter 1 / Introduction Processing Structure Properties I Performance Figure 1.1 The four components of the discipline of materials science and engineering and their interrelationship elationships among these four components in terms of the design, production, and utilization of materials, We now present an example of these processing-structure-properties-performance principles with Figure 1.2, a photograph showing three thin disk specimens placed over some printed matter. It is obvious that the optical properties (i.e. the light transmittance)of each of the three materials are different; the one on the left is trans- parent (i.e, virtually all of the reflected light passes through it), whereas the disks in the center and on the right are, respectively, translucent and opaque. All of these spec- imens are of the same material, aluminum oxide but the leftmost one is what we call a single crystal-that is, it is highly perfect-which gives rise to its transparency. The center one is composed of numerous and very small single crystals that are all con- nected; the boundaries between these small crystals scatter a portion of the light re flected from the printed page, which makes this material optically translucent Finall he specimen on the right is composed not only of many small, interconnected crys- ls, but also of a large number of very small pores or void spaces. These pores also effectively scatter the reflected light and render this material opaque. Thus, the structures of these three specimens are different in terms of crystal boundaries and pores, which affect the optical transmittance properties. Further- more, each material was produced using a different processing technique. And, of course, if optical transmittance is an important parameter relative to the ultimate in-service application, the performance of each material will be different. high degree of regular nw. eature that 0 the princ k struc- ture because the particles in a aguada a8u81-ouo\ Tids.A " -uid are jumbled and disor u they move about Figure 1.2 Photograph of three thin disk specimens of aluminum oxide, which have been laced over a printed page in order to demonstrate their differences in light-transmittance haracteristics. The disk on the left is transparent(that is, virtually all light that is reflected from the page passes through it), whereas the one in the center is translucent(meaning th some of this reflected light is transmitted through the disk ). And, the disk on the right is opaque-ie, none of the light passes through it. These differences in optical properties are a consequence of differences in structure of these materials, which have resulted from the way the materials were processed. (Specimen preparation, P. A Lessing: photography by S. Tanner

relationships among these four components in terms of the design, production, and utilization of materials. We now present an example of these processing-structure-properties-performance principles with Figure 1.2, a photograph showing three thin disk specimens placed over some printed matter. It is obvious that the optical properties (i.e., the light transmittance) of each of the three materials are different; the one on the left is trans￾parent (i.e., virtually all of the reflected light passes through it), whereas the disks in the center and on the right are, respectively, translucent and opaque.All of these spec￾imens are of the same material, aluminum oxide, but the leftmost one is what we call a single crystal—that is, it is highly perfect—which gives rise to its transparency. The center one is composed of numerous and very small single crystals that are all con￾nected; the boundaries between these small crystals scatter a portion of the light re￾flected from the printed page, which makes this material optically translucent. Finally, the specimen on the right is composed not only of many small, interconnected crys￾tals, but also of a large number of very small pores or void spaces. These pores also effectively scatter the reflected light and render this material opaque. Thus, the structures of these three specimens are different in terms of crystal boundaries and pores, which affect the optical transmittance properties. Further￾more, each material was produced using a different processing technique. And, of course, if optical transmittance is an important parameter relative to the ultimate in-service application, the performance of each material will be different. 4 • Chapter 1 / Introduction Figure 1.2 Photograph of three thin disk specimens of aluminum oxide, which have been placed over a printed page in order to demonstrate their differences in light-transmittance characteristics. The disk on the left is transparent (that is, virtually all light that is reflected from the page passes through it), whereas the one in the center is translucent (meaning that some of this reflected light is transmitted through the disk). And, the disk on the right is opaque—i.e., none of the light passes through it. These differences in optical properties are a consequence of differences in structure of these materials, which have resulted from the way the materials were processed. (Specimen preparation, P. A. Lessing; photography by S. Tanner.) Processing Structure Properties Performance Figure 1.1 The four components of the discipline of materials science and engineering and their interrelationship. 1496T_c01_01-14 12/20/05 7:11 Page 4 2nd REVISE PAGES

496Tc0101-1411/9/0517:02page5 REVISED PAGES EQA 1.4 Classification of materials 5 1.3 WHY STUDY MATERIALS SCIENCE AND ENGINEERING? Why do we study materials? Many an applied scientist or engineer, whether me- hanical, civil, chemical, or electrical, will at one time or another be exposed to a design problem involving materials. Examples might include a transmission gear, the superstructure for a building, an oil refinery component, or an integrated circuit chip. Of course, materials scientists and engineers are specialists who are totally involved in the investigation and design of materials. Many times, a materials problem is one of selecting the right material from the many thousands that are available. There are several criteria on which the final decision is normally based. First of all, the in-service conditions must be character ized, for these will dictate the properties required of the material. On only rare occasions does a material possess the maximum or ideal combination of properties. Thus, it may be necessary to trade off one characteristic for another. The classic ex- ample involves strength and ductility; normally, a material having a high strength will have only a limited ductility. In such cases a reasonable compromise between two or more properties may be necessary A second selection consideration is any deterioration of material properties that may occur during service operation. For example, significant reductions in mechanical strength may result from exposure to elevated temperatures or corrosive environments. Finally, probably the overriding consideration is that of economics: What will the finished product cost? A material may be found that has the ideal set of prop erties but is prohibitively expensive. Here again, some compromise is inevitable The cost of a finished piece also includes any expense incurred during fabrication to produce the desired shape The more familiar an engineer or scientist is with the various characteristics and structure-property relationships, as well as processing techniques of materials the more proficient and confident he or she will be to make judicious materials hoices based on these criteria 1.4 CLASSIFICATION OF MATERIALS Solid materials have been conveniently grouped into three basic classifications: met als, ceramics, and polymers. This scheme is based primarily on chemical makeup and atomic structure, and most materials fall into one distinct grouping or another, although there are some intermediates. In addition, there are the composites, com- binations of two or more of the above three basic material classes. A brief explana tion of these material types and representative characteristics is offered next. Another classification is advanced materials-those used in high-technology applications- viz. semiconductors, biomaterials, smart materials, and nanoengineered materials; hese are discussed in Section 1.5 Metals Materials in this group are composed of one or more metallic elements(such as iron, aluminum, copper, titanium, gold, and nickel), and often also nonmetallic elements(for example, carbon, nitrogen, and oxygen) in relatively small amounts. Atoms in metals and their alloys are arranged in a very orderly manner(as discussed in Chapter 3), and in comparison to the ceramics and polymers, are relatively dense(Figure 1.3). With The term metal alloy is used in reference to a metallic substance that is composed of two or more elements

1.3 WHY STUDY MATERIALS SCIENCE AND ENGINEERING? Why do we study materials? Many an applied scientist or engineer, whether me￾chanical, civil, chemical, or electrical, will at one time or another be exposed to a design problem involving materials. Examples might include a transmission gear, the superstructure for a building, an oil refinery component, or an integrated circuit chip. Of course, materials scientists and engineers are specialists who are totally involved in the investigation and design of materials. Many times, a materials problem is one of selecting the right material from the many thousands that are available. There are several criteria on which the final decision is normally based. First of all, the in-service conditions must be character￾ized, for these will dictate the properties required of the material. On only rare occasions does a material possess the maximum or ideal combination of properties. Thus, it may be necessary to trade off one characteristic for another. The classic ex￾ample involves strength and ductility; normally, a material having a high strength will have only a limited ductility. In such cases a reasonable compromise between two or more properties may be necessary. A second selection consideration is any deterioration of material properties that may occur during service operation. For example, significant reductions in mechanical strength may result from exposure to elevated temperatures or corrosive environments. Finally, probably the overriding consideration is that of economics: What will the finished product cost? A material may be found that has the ideal set of prop￾erties but is prohibitively expensive. Here again, some compromise is inevitable. The cost of a finished piece also includes any expense incurred during fabrication to produce the desired shape. The more familiar an engineer or scientist is with the various characteristics and structure–property relationships, as well as processing techniques of materials, the more proficient and confident he or she will be to make judicious materials choices based on these criteria. 1.4 CLASSIFICATION OF MATERIALS Solid materials have been conveniently grouped into three basic classifications: met￾als, ceramics, and polymers.This scheme is based primarily on chemical makeup and atomic structure, and most materials fall into one distinct grouping or another, although there are some intermediates. In addition, there are the composites, com￾binations of two or more of the above three basic material classes. A brief explana￾tion of these material types and representative characteristics is offered next.Another classification is advanced materials—those used in high-technology applications— viz. semiconductors, biomaterials, smart materials, and nanoengineered materials; these are discussed in Section 1.5. Metals Materials in this group are composed of one or more metallic elements (such as iron, aluminum, copper, titanium, gold, and nickel), and often also nonmetallic elements (for example, carbon, nitrogen, and oxygen) in relatively small amounts.3 Atoms in metals and their alloys are arranged in a very orderly manner (as discussed in Chapter 3), and in comparison to the ceramics and polymers, are relatively dense (Figure 1.3).With 1.4 Classification of Materials • 5 3 The term metal alloy is used in reference to a metallic substance that is composed of two or more elements. 1496T_c01_01-14 11/9/05 17:02 Page 5 REVISED PAGES