试谈材料相关概论

1、试谈材料相关概论Classification of Materialsl Basis of classification: atomic structures nature of chemical bonds:金属键金属键 Metallic bond离子键离子键 Ionic bond共价键共价键 Covalent bond范德华健范德华健 Van der Waals bond氢键氢键 Hydrogen bond2 Classification（按按物理化学属性物理化学属性） Metallic materials 金属材料金属材料 Inorganic-nonmetallic materials

2、无机非金属材料无机非金属材料 Polymeric materials 有机高分子材料有机高分子材料 Composite materials 复合材料复合材料3Propertiesl Mechanical properties: the behavior of materials deformed by a set of forces. Physical properties: the behavior of materials subjected to the action of temperature, electric or magnetic fields, or light. Chemi

3、cal properties: the behavior of material in a reactive environment.4The four basic aspects of materials science and technology 51.Types of Materials MetallCharacteristics / propertiesis strong;can be readily formed into practical Its ductility is an important asset in permitting small amounts of yie

4、lding to sudden and severe loads. 6l Types Ferrous metals: pig iron, carbon steel, pure iron Non-ferrous metals: heavy, light, valued and rare metals Special metals: non-crystalline, shape memory alloy7CeramicslCharacteristics / properties: brittlelRecent development in technologylStructural feature

5、: crystalline: the constituent atoms are stacked together in a regular, repeating pattern. noncrystalline: the atoms are stacked in irregular, random patterns. glass: noncrystalline solids8PolymerslComposition: hydrogen and carbon, oxygen lPropertiesLightweightlow-cost low strength low melting point

6、, andhigher chemical reactivity 93. Structural Characteristic of Materials4. 5.Forms of solids: crystalline & amorphous Crystalline: an ordered arrangement of the elementary particles (ions, atoms or molecules). 晶体结构晶体结构: 晶体中原子（或离子）在空晶体中原子（或离子）在空 间规则排列的方式。间规则排列的方式。103.1 Properties of crystalsDep

7、end on:the electronic structure of atoms the nature of the interactions in the crystalthe spatial arrangement of elementary particles, and the composition, size and shape of crystals. 11 Anisotropy 各向异性各向异性: The properties of crystals are different in various crystallographic directions, which are a

8、ssociated with an ordered arrangement of atoms (ions, molecules) in space. This phenomenon is called anisotropy. 123.2 Crystal Lattice 晶格晶格 Arrangement of elementary particles in a crystal (a): three-dimensional view (b): scheme13 Types of elementary cell: simple three-dimensional lattice 简单立方格子简单立方

9、格子 body-centred cell 体心立方格子体心立方格子 face centred cell 面心立方格子面心立方格子14Types of elementary cell in crystal lattices (a): simple (b): body-centred cell (c): face centred cell 154. Structure-Property-Processing 5. Relationship 4.1 Properties 力学性能力学性能 Mechanical property 强度强度 Strength在外力作用下材料抵抗塑性变形或在外力作用下材料

10、抵抗塑性变形或断裂的能力称为强度。单位断裂的能力称为强度。单位MPa。16抗压强度抗压强度 Compressive strength- 材料破坏之前所能够承受的最大压应力材料破坏之前所能够承受的最大压应力PP17抗拉强度抗拉强度 Tensile strength- 材料破坏之前所能够承受的最大拉应力材料破坏之前所能够承受的最大拉应力PP18 弹性模量弹性模量 Modulus of elasticity 硬度硬度 Hardness材料抵抗硬物压入其表面的能力，材料抵抗硬物压入其表面的能力，即抵抗局部塑性变形的能力即抵抗局部塑性变形的能力。 韧性韧性 Toughness材料抵抗裂纹萌生与扩展的能力

11、材料抵抗裂纹萌生与扩展的能力。 疲劳特性疲劳特性 Fatigue behaviour19 物理和化学性能物理和化学性能 Physicochemical property 电性能电性能 Electric properties- 导电性导电性 Electric conductivity以材料的电阻率或电导率评价以材料的电阻率或电导率评价。- 介电介电 性性 Dielectric properties 能把带电体分开并能长期经受强电能把带电体分开并能长期经受强电 场作用的绝缘材料叫介电材料或电场作用的绝缘材料叫介电材料或电 介质介质。20 压电性压电性 Piezoelectricity介电材料在应力

12、作用下发生尺寸变介电材料在应力作用下发生尺寸变化时因极化而产生电场或电压，这化时因极化而产生电场或电压，这种现象称为压电性种现象称为压电性。 铁电性铁电性 Ferroelectricity 有些离子晶体没有外电场作用也能有些离子晶体没有外电场作用也能表现出很强的电偶极矩，这种能自表现出很强的电偶极矩，这种能自发极化的现象叫铁电效应发极化的现象叫铁电效应。21 磁性能磁性能 Magnetic properties 抗磁性物质抗磁性物质 Antimagnetic 减弱磁场减弱磁场 顺磁性物质顺磁性物质 Paramagnetic 使磁场略有增加使磁场略有增加 铁磁性物质铁磁性物质 Ferromagn

13、etic 使磁场强裂增加使磁场强裂增加22 热性能热性能 Thermal properties 吸热吸热：热容；传热：热导率；热容；传热：热导率； 膨胀：热膨胀系数膨胀：热膨胀系数 光学性能光学性能 Optical properties吸收、透射、反射吸收、透射、反射234.2 Structurel Structural levels:Macrostructure: visible with eyes or optical microscope;Meso-structure: Optical or SEM, ranging 10-710-4m;Microstructure: Arrangeme

14、nts of atoms and molecules.244.3 Processing lFor metalsCasting 铸造: by pouring liquid metal into a mold Welding 焊接/ brazing铜焊 / soldering锡焊 / adhesive bonding: joining individual pieces of metal 25Forging 锻造/ drawing拉拔 / extrusion 挤压/ rolling碾压 / bending弯曲: forming the solid metal into useful shapes

15、using high pressuresPowder metallurgy: compacting tiny metal powder particles into a solid massMachining: removing excess materials26lFor ceramicscasting, forming, extrusion, compactionheat treatment at high temperatures to drive off the fluids and to bond the individual constituents together. For p

16、olymers by injection of softened plastic into molds, drawing and forming. 274.4 Structure-property-processing interaction lProcessing: affecting structure & properties lProcessing: determined by structure & properties 28Summary: lDefinition of materialslClassification of materialslChacterist

17、ics of each type of materialslChemical bondslStructure feature of crystallPrperties of materialsProblems: : Page 33 1.3 1.4 1.8 1.11 1.13 1.1629Chapter 3 Ceramic Materials30陶瓷材料的概念与分类 Concept and classification陶瓷材料的制作工艺 Manufacture processing technologies陶瓷材料的性能及应用 Properties and application 311 陶瓷的

18、概念和分类 Concept and Classifications 1.1 概念 Concept3.1 Introduction321 陶瓷的概念和分类 Concept and Classifications 1.1 概念 Concept陶瓷陶瓷Ceramic: 烧过的粘土。是陶器 (pottery)和瓷器(porcelain)的总称。3.1 Introduction331 陶瓷的概念和分类 Concept and Classifications 1.1 概念 Concept陶瓷陶瓷Ceramic: 烧过的粘土。是陶器 (pottery)和瓷器(porcelain)的总称。3.1 Introd

19、uction34 Ceramic compounds: can be defined as inorganic compounds made by heating clay or other mineral matter to a high temperature at which they partially melt and bond together. 定义定义:陶瓷指经过高温处理所合成的无 机非金属材料 (Inorganic & nonmetallic materials),简称无机材料。35陶瓷材料的特性陶瓷材料的特性: 离子键或共价键 ion or covalent bon

20、d 强度高,硬度大,脆性 high strength, rigid, brittle 耐热,电绝缘性能好 high thermal resistance, electrical insulator (at high temperature, ion bond materials are conductive) 多晶 polycrystalline compounds 36 Usually compound between metallic and nonmetallic elements Always composed of more than one element Bonds are pa

21、rtially or totally ionic, and can have combination of ionic and covalent bonds Majority has ionic (in salt compounds) or metallic and nonmetallic elements (as in oxides Al2O3, MgO, SiO2)37主要组分主要组分：硅酸盐化合物硅酸盐化合物 在美国，陶瓷泛指硅酸盐材料，又称为传统陶瓷或普通陶瓷。包括日用陶瓷、工业用陶瓷、一般玻璃、水泥、耐火材料等。 先进无机材料先进无机材料 (advanced inorganic ma

22、terials): 用氧化物氧化物、氮化物氮化物、硅化物硅化物、碳化碳化 物物以至各种无机非金属化合物经过 特殊特殊的先进工艺工艺制成的材料。 38Ceramicstraditional ceramics: derived and processed from clay or nonclay minerals including refractories（耐火材料（耐火材料), white wares, cement(水泥水泥), porcelain(瓷器瓷器), and structural clay ceramics. advanced ceramics: high purity, bet

23、ter mechanical, electrical, magnetic, and optical properties 1.2 分类 Classification391.2.1 传统陶瓷 Traditional ceramics： 又称普通陶瓷，主要是指以天然无 机物如粘土粘土等为主要原料、经高温高温 处理处理得到的制品，主要用于制造日 用器皿、生活洁具等生活用具。401.2.1 传统陶瓷 Traditional ceramics： 又称普通陶瓷，主要是指以天然无 机物如粘土粘土等为主要原料、经高温高温 处理处理得到的制品，主要用于制造日 用器皿、生活洁具等生活用具。瓷器瓷器 Porcela

24、in; Chinaware ：细密的陶 瓷器皿，质硬、半透明、白色、发 声清脆以及无孔，以长石长石 (Feldspar)、石英石英（Quartz）和高岭石高岭石 （Kaolin）为基本原料经一次烧成。4142Traditional Ceramics43艺术陶瓷艺术陶瓷44内墙砖内墙砖45卫生洁具卫生洁具-洗面器洗面器461.2.2 先进陶瓷 Advanced ceramics： 又称为精细陶瓷、新型陶瓷、高 技术陶瓷、特种陶瓷等。是指以 精制的高纯天然无机物高纯天然无机物或人工合 成无机化合物为原料，采用精密精密 控制的制造加工工艺烧结控制的制造加工工艺烧结，得到 的具有独特性能的高功能陶瓷。

25、47 先进陶瓷，从原料原料、显微结构显微结构中所体现的晶粒、晶界、气孔、缺陷等在尺度上都是处在微米级微米级的水平，因此可以称之为微米级先进陶瓷微米级先进陶瓷。 48 先进陶瓷，从原料原料、显微结构显微结构中所体现的晶粒、晶界、气孔、缺陷等在尺度上都是处在微米级微米级的水平，因此可以称之为微米微米级先进陶瓷级先进陶瓷。 Advanced ceramic，the scale of the raw materials and microstructures, including the crystal grains, crystal interface, pores and defects is a

26、t the level of micron. We also call it micron-level ceramic.49Advanced Ceramics Cutting tools Zirconia toughened alumina 氧化锆增强氧化铝氧化锆增强氧化铝50红色陶红色陶瓷系列瓷系列黑色陶黑色陶瓷系列瓷系列 黄色陶黄色陶瓷系列瓷系列51打火机陶瓷系列打火机陶瓷系列52密封环陶瓷系列密封环陶瓷系列53点火头系列点火头系列541.2.3 先进陶瓷的分类 组成 composition：氧化物氧化物 oxide 、氮氮 化物化物 nitride 、 硅化物硅化物 silicide、碳

27、碳 化物化物 carbide 陶瓷 性能 properties & applications：结构陶结构陶 瓷瓷 structural ceramics、功能陶瓷功能陶瓷 functional ceramics55结构陶瓷结构陶瓷:以力学机械性能为主。 功能陶瓷功能陶瓷:利用材料的电、磁、光、 声、热等性能及其耦合效应，如 铁电、压电陶瓷、敏感陶瓷、快 离子导体陶瓷等。以及主要从电 性能上考虑有绝缘陶瓷、介电陶 瓷、半导体陶瓷、导体陶瓷以至 高临界温度的超导陶瓷。5657581.3 陶瓷的发展59陶陶 器器 瓷器（传统瓷器（传统 陶陶 瓷瓷 ）高铝质粘土和高铝质粘土和瓷土的应用瓷土的应

28、用釉釉 的的 发发 明明原原 料料 纯纯 化化陶瓷工艺的陶瓷工艺的 发展发展 陶瓷理论的陶瓷理论的发展发展 先先 进进 陶陶 瓷（微米级）瓷（微米级）纳纳 米米 陶陶 瓷瓷高温技术高温技术的发展的发展 显微结构显微结构 分析的进步分析的进步性能研究性能研究 的深入的深入无损评估无损评估的成就的成就相邻学科相邻学科的推动的推动图1 陶瓷发展的阶段1.3 陶瓷的发展601.4 Applications Thermal Barrier Coatings: Low thermal conductivity reduces metal temperatures61 Electronics Packagi

29、ng: Ceramics: provide high temperature performance and thermal expansion coefficient match to Silicon High thermal conductivity desired (e.g. AlN)62 Ceramic Armour 装甲装甲Absorption of projectile energy吸收子弹发射的能量吸收子弹发射的能量63hydboneHuman bone64 Jet-Engine turborotor关节关节651.4 陶瓷的发展趋向 纳米陶瓷 nano-ceramic特性特性：

30、 （1）原材料粉末原材料粉末 raw materials powder 颗粒为纳米级为纳米级 nano-level grains； （2）微观结构微观结构 microstructures, 晶粒 grains, 晶界 interfaces，气孔 pores 以及 晶体缺陷 defects 同样在纳米同样在纳米 级级 nano-level。66 多相复合陶瓷 Multi-phase combination ceramics 纤维或晶须补强陶瓷纤维或晶须补强陶瓷：以陶瓷为基体，以各种组分的纤维或晶须作为纤维或晶须作为补强剂补强剂所组成的多相复合结构的复合材料。67纤维或晶须补强陶瓷68 颗粒弥散型

31、复合陶瓷颗粒弥散型复合陶瓷：在陶瓷基体 中加入弥散的不同化学组成的第二弥散的不同化学组成的第二 相颗粒（相颗粒（产生弥散强化）所组成的 复相陶瓷。69 颗粒弥散型复合陶瓷颗粒弥散型复合陶瓷：在陶瓷基体 中加入弥散的不同化学组成的第二弥散的不同化学组成的第二 相颗粒（相颗粒（产生弥散强化）所组成的 复相陶瓷。颗粒弥散型复合陶瓷70 两种晶型复合的复相陶瓷两种晶型复合的复相陶瓷：同一化 学组成的物质经适当的工艺控制， 得到不同晶型和不同的颗粒形貌不同晶型和不同的颗粒形貌的 复相陶瓷，达到自补强自补强的目的。71 两种晶型复合的复相陶瓷两种晶型复合的复相陶瓷：同一化 学组成的物质经适当的工艺控制，

32、得到不同晶型和不同的颗粒形貌不同晶型和不同的颗粒形貌的 复相陶瓷，达到自补强自补强的目的。 有机和无机复合的复相陶瓷有机和无机复合的复相陶瓷：介于 有机与无机材料之间，不需要高温 处理而获得的一种新型材料。72 两种晶型复合的复相陶瓷两种晶型复合的复相陶瓷：同一化 学组成的物质经适当的工艺控制， 得到不同晶型和不同的颗粒形貌不同晶型和不同的颗粒形貌的 复相陶瓷，达到自补强自补强的目的。 有机和无机复合的复相陶瓷有机和无机复合的复相陶瓷：介于 有机与无机材料之间，不需要高温 处理而获得的一种新型材料。 金属陶瓷金属陶瓷：金属与陶瓷复合的复相 陶瓷。733.2 Nature of Ceramics

33、 Crystalline solids composed of metallic and nonmetallic materialsCeramics are crystal structures made of metallic ionsInorganic materials Bonding is either partially or completely ionic. Variables involved are (1)the magnitude of the electrical charge on the ions;(2)the relative size of the ions 74

34、 Ceramics are inexpensive compared with competing materials. Consisting of silicon, aluminum, and oxygen: the most abundant elements in the earths crustceramics can be produced at less cost than that of competing metal-alloy components. Properties of Ceramics75What sets ceramics apart is their set o

35、f properties common to nearly all forms: extreme hardness, heat resistance, corrosion resistance, low electrical and thermal conductivity, and low ductility, or brittleness. 76 Applications for advanced ceramics:use as parts in a future ceramic heat enginegood candidates for wear-resistance applicat

36、ionsElectrical properties place ceramics in great demand as solid electrolytes in experimental batteries and fuel cells. 77Other uses include:automotive sensorspackaging for integrated circuitselectronic/optical devicesfiber opticsmicrochips, andmagnetic heads. 78In the marriage of the computer and

37、communications technologies, ceramics play a major role. Replacements for human boneChemical inertness of ceramics is finding many applications in the medical field Ceramics play a big role in the machine-tool industry. Their thermal and mechanical stability allows them to retain their smooth, accur

38、ate cutting surfaces longer than metals do. 79Coated cutting tools and inserts, some with as many as 12 extremely thin coatings, each designed to serve a special function, can run productively at faster cutting speeds and at faster feed rates than can any metal-alloy tool in the machining of hard st

39、eels, superalloys, and ceramics. 80 Corrosion resistance, chemical inertness, thermal shock resistance, and other properties that materials scientists and engineers can design into ceramic materials make both traditional and advanced ceramics highly attractive in a large number of applications. 81 材

40、料科学家和工程师们能够将耐腐蚀性、材料科学家和工程师们能够将耐腐蚀性、化学惰性、抗热震性设计到陶瓷材料中，化学惰性、抗热震性设计到陶瓷材料中，使传统陶瓷和先进陶瓷在广泛的应用中使传统陶瓷和先进陶瓷在广泛的应用中都具有很强的吸引力。都具有很强的吸引力。 82 Porosity and Density Mass density, which uses the mass of a material divided by its volume refers to this theoretical densityAtomic weight is a major factor in determining

41、 the density of a materialClose-packed metals are more dense than open-structured materials. 83 The optimum density of spherical particles can be reached by varying the size distribution of particles to permit smaller particles (50 nm or less) to locate in the interstices(空隙）空隙）of the larger ones. O

42、ne disadvantage with this procedure is that the larger particles tend to grow excessively during high-temperature sintering, which takes place later in the process. 84Defects in ceramics can develop due to internal stresses（内内应力）应力） and porosityThermal stresses due to an-isotropic thermal expansion

43、tend to crack weak grain boundaries96% dense alumina Brittle Fracture of Ceramics85Pores in partially sintered Alumina86 Ceramics are, by nature, generally porous materials with varying degrees of porosity. bulk density is used in this instance to refer to a ceramics density, and it includes the materials porosity and the fact that most ceramics contain both a crystalline and a noncrystalline phase.87 Green density is the bulk