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1、Fundamentals of materials science and engineering,材料科学与工程基础,School of materials Science and Engineering 材料科学与工程学院,Introduction,Chapter 1,Historically, the development and advancement of societies have been intimately tied to the members ability to produce and manipulate materials to fill their needs
2、. In fact, early civilizations have been designated by the level of their materials development,Materials are probably more deep-seated in our culture than most of us realize.,1.1 Historical Perspective,Stone age,Bronze age,Iron age,Steel age,Advanced material age,Stone,Bronze (Cu-Sn alloy), 中国商代司母戊
3、大方鼎 (公元前1411世纪),Iron,Structures,Properties,investigating,relationships,Designing or engineering the structure of a material to produce a predetermined set of properties,On the basis of these correlations,Materials engineering,1.2 Materials Science and Engineering,Subatomic structure (原子内) involves e
4、lectrons within the individual atoms and interactons with their nuclei Atomic level structure (原子间) encompasses the organization of atoms or molecules relative to one another,“Structure” of a material usually relates to the arrangement of its internal components.,Microscopic structure larger structu
5、ral realm contains large groups of atoms that are normally agglomeraged together be subject to direct observation using some type of microscope Macroscopic structure the structural elements that may be viewed with the naked eye,“Property”: while in service use, all materials are exposed to external
6、stimulation that evoke some type of response.,For example:,Subjected to force deformation Polished metal surface reflect light,Generally, definitions of properties are made independent of material shape and size,Mechanical properties,Electrical properties,Thermal behavior,Magnetic properties,Optical
7、 properties,Deteriorative characteristics,Six different important properties,There is a characteristic type of stuimulus capable of provoking different responses,Properties 性 质,The four components of the discipline of materials science and engineering and their liner interrelationship,The structure
8、of a material will depend on how it is processed. A materials performance will be a function of its properties.,We draw attention to the relationships among these four components in terms of the design, production, and utilization of materials.,Figure 1.2 Photograph showing the light transmittance o
9、f three aluminum oxide specimens. From left to right: single crystal material (sapphire), which is transparent; a polycrystalline and fully dense (nonporous) material, which is translucent; a polycrystalline material that contains approximately 5% porosity, which is opaque.,Each material was produce
10、d using a different processing technique,Many an applied (mechnaical, civil, chemical, or electrical) scientist or engineer will at one time or another be exposed to a design problem involving materials.,Example:,transmission gear, integrated circuit chip ,1,Materials scientists and engineers invest
11、igation and design of materials,1.3 Why Study Materials Science and Engineering,Many time, a materials problem is one of selecting the right material from the many thousands that are available.,Several criteria:,First of all, the in-service conditions must be characterized, for these will dictate th
12、e properties required of the material.,2,trade off one characteristic for another.,strength and ductility,The classic example :,A second selection consideration is any deterioration of material properties that may occur during service operation.,For example :,Exposure to elevated temperatures or cor
13、rosive environments result in significant reductions in mechanical strength,Some compromise is inevitable,Finally, probably the overriding consideration is that of economics.,A material,has ideal set of properties,is prohibitively expensive,What will the finished product cost?,Also includes any expe
14、nse incurred during fabrication to produce the desired shape.,1.4 Classification of Materials,A familiar item that is fabricated from three different material types is the beverage container.,Beverages are marketed in aluminum (metal) cans, glass (ceramic) bottles, plastic (polymer) bottles,based pr
15、imarily on chemical makeup and atomic structure:,metals, ceramics, polymers 金属 陶瓷 聚合物,most materials fall into one distinct grouping or another, although there are some intermediates,based on engineering:,composites, semiconductors, biomaterials 复合材料 半导体材料 生物材料,Many properties:,Metals,combinations o
16、f metallic elements,Chemical makeup:,have large numbers of nonlocalized electrons（离域电子）,Structure characteristic:,extremely good conductors of electricity and heat,not transparent to visible light,lustrous appearance strong,deformable,Ceramics,compounds between metallic and nonmetallic elements,Chemical makeup:,Compounds are most frequently oxides, nitrides, and carbides.,Wide range of materials
