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1、Definition 材料的定义：The materials making up the surrounding world consist of discrete particles, having a submicroscopic size. Atomic structure and the nature of bonds(原子结构和化学键) metals and their alloys (metallic bonding 金属键) organic polymers 有机聚合物(covalent bonding and secondary bonding 共价键和二次键) ceramic
2、s (ionic bonding and covalent bonding) Mechanical properties：力学性能 Which reflect the behavior of materials, deformed by a set of forces （概念） Four basic types of stresses : tensile, compressive, shear ,torsion (拉力，压力，剪切力，扭转力) Physical properties:物理性能 the behavior of materials subjected to the action o
3、f temperature, electric or magnetic fields, or light. 电性能Electric properties 磁性能Magnetic properties 热性能Thermal properties 光性能Optical properties Chemical properties:化学性能 Which characterize the behavior of material in a reactive environment. （概念） The four basic aspects of materials science and technol
4、ogy are: manufacturing processing, structure, properties and performances 结构性能工艺之间的关系： First, the processing of a material affects the structure, second the original structure and properties determine how we can process the material to produce a desired shape 一、METAL:（金属） 1、金属最显著的特性：good conductors
5、of heat and electricity (热导性，电导性) 2、性能:are opaque to visible light; are hard, rigid; can undergo plastic deformation; have a high melting temperature 3、金属的晶体点阵： crystal structure（晶体结构） : body-centered cubic structure , face-centered cubic structure , hexagonal close-packed structure（体型、面型，六角形放射状） 4、
6、properties of alloys（合金的性能） :(more carbon ,more brittle.) have relatively high thermal and electrical conductivities; good energy absorption characteristics nonmagnetic properties 5、铸铁概念：cast iron, essentially an alloy of iron, carbon and silicon, is composed of iron and from 2 to 6.67 percent carbo
7、n, plus manganese, sulfur, and phosphorus, and shaped by being cast in a mold. 6、The types and properties of cast iron ； white cast iron( hard , brittle ) , gray cast iron (brittle ,withstand large compressive loads but small tensile loads ), alloy cast iron , nodular or ductile cast iron (good cast
8、ability ,toughness, good wear resistance ,low melting point ,and hardenability ), malleable cast iron (strength ,toughness, ductility ,and machinability) 7、carbon steels（碳钢）：low carbon steels（含碳0.050.32%）；medium carbon steels（含碳 0.350.55%）；high carbon steels（含碳0.601.50%） 8、不锈钢：there are three types
9、of stainless steels: -the martensitic types；the ferritic types ；the austenitic types 9、advantages of using Al: one-third of the weight of steel good thermal and electrical conductivity ;high strength-to-weight ratio ;can be given a hard surface by anodizing and hard coating ;most alloys are weldable
10、 ;will not rust ;high reflectivity ;can be die cast ;easily machined ;good formability; nonmagnetic nontoxic and one third of the stiffness of steel. 10、copper is known for its high thermal (热导性)and electrical conductivity. 11、crystal structure : body-centered cubic structure (barium), face-centered
11、 cubic structure (copper), hexagonal close-packed structure (zinc) 二、CERAMIC（陶瓷） 1、The property of ceramics （陶瓷的性质） Extreme hardness（硬度高） Heat resistance Corrosion resistance Low electrical and thermal conductivity Low ductility (brittleness) 2、Porosity（孔隙度） Open porosity: refers to the network of p
12、ores in a material that is open to the surface and into which a liquid such as water can penetrate if the part were submerged in it。 Closed porosity: refers to those pores that have become sealed within the grain structure 。 Pores affect the strength of ceramics in two ways：（影响强度的毛孔陶瓷两种方式） 、they pro
13、duce stress concentrations. Once the stress reaches a critical level, a crack will form and propagate. 、pores reduce the cross-sectional areas over which a load can be applied and, consequently, lower the stress that these materials can support。 Conventional ceramic processing（传统陶瓷处理）； manufacture o
14、f the powder ,its calcinations ,milling ,grading and mixing ,incorporating additives ,shape forming , drying and densification. 三、GLASS（玻璃） 1、the measured mechanical strength of glass is much lower than the theoretical strength causes of this loss of strength ： 、the presence of surface defects, such
15、 as caused by chemical corrosion or mechanical abrasion。 、If the glass is cooled too rapidly it does not have time to release stresses set up within it during cooling . these are frozen-in and can cause the glass to shatter when it becomes a solid. the transparency is explained by two properties : f
16、irst ,it has no surface of internal structure which gives reflection or scattering。 second ,it has no free electrons which can interact with the electron magnetic nature of wave motion including visible light 五、POLYMER（聚合物） A Polymers is macromolecule (大分子）built up by the linking together of large numbers of much smaller molecules 性能：low strength, low melting point flexible easily to be formed into different s
