第二讲 材料科学与工程专业英语 文献选读
材料科学与工程 专业外语 2
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Diamond structure in a different orientation showing the tetrahedral structure a bit more clearly. As above, carbon atoms at the corners of the tetrahedral are dark gray, those in the middle are light gray
Chemistry and Advanced Materials; Materials Research: Today and Future
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Structure-Property Relationships of Materials；
Structure of Materials
It should be clear that all matter is made of atoms. From the periodic table, it can be seen that there are only about 100 different kinds of atoms in the entire Universe. These 100 atoms form thousands of different substances ranging from the air we breathe to the metal used to support tall buildings. Metals behave differently than ceramics, and ceramics behave differently than polymers. The properties of matter depend on which atoms are used and how they are bonded together.
材材料科学与工程专业英语
2.6 semiconductorFollowing the discussion of intrinsic ,elemental semiconductors we note that the fermi function indicates that the number of charge carriers increases exponentially with temperature. This effect so dominates the conductivity of semiconductors that conductivity also follows an exponential increase with temperature(an example of an arrhenius equation ).This increase is in sharp contrast to the behavior of metals.We consider the effect of impurities in extrinsic,elemental semiconductors.Doping a group IV a material(such as Si) with a group V a impurity (such as P)produces an n-type semiconductor in which negative charge carriers(conduction electrons)dominate.The “extea”electron from the group V A addition produces a donor level in the energy band structure of the semiconductor.As with instrinsic semiconductors,extrinsic semiconduction exhibits arrhenius behavior.in n-type material, the temperature span between the regions of extrinsic and insrinsic behavior is called the exhaustion range .A p-type semiconductor is produced by doping a group IV a material with a group III a impurity(such as Al).The group III A element has a “missing” electron producing anacceptor level in the band stucture and leading to formation of positive charge carriers (electron holes). The region between extrinsic and instrinsic behavior for p-type semiconductors is called the saturation range . Hall effect measurements can distinguish between n-type and p-type conduction.Compound semiconductors usually have an MX composition with an average of four valence electrons per atom .The III-V and II-VI compounds are the common examples .amorphous semiconductors are the non-crystalline materials with semiconducting behavior.Elemental and compound material are both found in this category .To appreciate the applications of semiconductors,we review a few decades.the solid state rectifier (or diode) contains a single p-n junction .Current flows readily when this junction is forward biased but is almost completely choked off when reverse biased.the transistor is a device consisting of a pair of nearby pn junctions.The net result is a solid state amplifier. Replacing vacuum tubes with solid state elements such as these produced substantial miniaturization of electrical circuits.Further miniaturization has resulted by the production of microcircuis consisting of precise parrerns of n-type and p-type regions ona single crystal chip.The major electrical properties needed to specify an intrinsic semiconductor are band gap,electron mobility,hole mobility,and conduction electron density (=electron hole density ) at room temperature.For extrinsic semiconductors,one needs to specify either the donor level (for n-type material) or the acceptor level (for p-type material).2.7 compositesOne category of structural engineering material is that of composites .These materials involve some combination of two or more components from the “fundamental” materal types .A key philosophy in selecting composite materials is that they provide the “best of both worlds”that is ,attrative properties from each component. A classic example is fiberglass.The strength of small diameter glass fibers is combined with the ductility of the polymetric matrix.The combination of these two components provides a product superior to either component alone .Many composites,such as fiberglass,involve combinations that cross over the boundaries of different kinds of materials. Others,such as concrete,involve different component from within a single material type.In general,we shall use a fairly narrowdefinition of composites.We shall consider only thode material thata combine different components on the microscopic(rather than macroscopic )scale .We shall noot include multiphase alloys and ceramics ,which are the result of routine processing.Similarly,the microcircuits be discussed later are not include because each component retains its distinctive character in these material systems. In spite of these restrictions,we shall find this category to include a tremendously diverse collection of materials,from the common to some of most sophisticated.We shall consider three categories of composites mateials. Conveninently ,these categories are demonstrated by three of our most common structural material ,fiberglass ,wood,and concrete .Fiberglass(or glass fiber reinforced polymer ) is an excellent example of a human made fiber reinforced composite.The glass-polymer system is just one of many important example .The fiber reinforcement is generally found in one of three primary configutations: aligned in a single direction ,randomly chopped,or woven in a fabric that is laminated with the matrix.Wood is a stuctural analog of fiberglass ,that is ,a natural fiber reinforced composite.The fibers of wood are elongated,biological cells. The matrixcorresponds to lignin and hemicellulose deposits.concrete is our best example of an aggregate composite, in which particles rather than fibers reinforce amatrix common concrete is rock and sand in a calcium aluminosilicate (cement)matrix.While concrete has been a construction material for centuries ,these are numerous c composites developed in recent decades that use a similar particulate reinforcement concept.The concept of property averaging is central to understanding the utility of composite material.an important example is the elastic modulus of a composite .The modulus is a sensitive function of the gemetry of the reinforcing component.similarly important is the srength of the interface betweeen the reinforcing component and the matrix .We sahll concentrate on these mechanical properties of composites in regard for their wide use as structural materials.So caaled “advanced”composites have provided some unusually attractive features,such as high strrenth to weight ratios.Some care is required in citing these properties,as they can be highly directional in nature.2.6there are numerous uses of piezoelectrics. for instance, plates cut from a single crystal can exhibit a specific natural resonance frequency(i.e., the frequency of an electromagneticwave that causes it to vibrate mechanically at the same frequency); these can be used as a frequency standard in highly stable crystal controlled clocks and in fixed frequency communications devices. other resonant applications include selective wave filters and transducers(e.g., for ultrasonic cleaning and drilling) and non-resonant devices(e.g., accelerometers, pressure gauges, microphone pickups) are dominated by ceramic piezoelectrics.2.7.3 fiberglass was a convenient and familiar example of fiber reinforced composites. Similarly ,concrete is an excellent example of an aggregate composite. As with wood,this common construction material is used in staggering quantities. The weight of concrete used annually exceeds that of all metals combined.For concrete, the term “aggregate” refers to a combination of sand(fine aggregate) and gravel(coarse aggregate). This component of concrete is a “natual” material in the same sense as wood. Ordinarily ,these materials are chosen for their relatively high density and strength. A table of aggregate compositions would be complex and largely meaningless. In general, aggregate materials are geological silicates chosen from locally available deposits. As such, these materials arecomplex and relatively impure examples of the crystalline silicates. Igneous rocks are common examples. “igneous” means solidified from a molten state. For quickly cooled igneous rocks ,some fraction of the resulting material may be non-crystalline, corresponding to the glassy silicates. The relative particle sizes of sand and gravel are measured(and controlled) by passing these materials through standard screens(or sieves). The reason for a combination of fine and coarse aggregate in a given concrete mix is that the space is more efficiently filled by a range of particle sizes. The combination of fine and coarse aggregate accounts for 60 to 75 percent of the total volume of the final concrete.Modern concrete uses portland cement,which is a calcium aluminosilicate. There are five common types of portland cement. They vary in the relative concentrations of four calcium containing minerals. The matrix is formed by the addition of water to the appropriate cement powder. The particle sizes for the cement powers are relatively small compared to the finest of the aggregates. Variation in cement particle size can strongly affect the rate at which the cement hydrates. As one might expect from inspecting the complex compositions of portland cement, the chemistry of the hydration process isequally complex.In ploymer technology, we noted several “additives” which provided certain desirable features to the end product. In cement technology , there are a numble of admixtures,which are additions providing certain features. Any component of concrete other than aggregate,cement,or water is, by definition ,an admixture. One of the admixtures is an “air entrainer” which reminds us that air can be thought of as a fourth component of concrete. The air entrainer admixture increases the concentration of entrapped air bubbles, usually for the purpose of workability(during forming) and increased resistance to freeze thaw cycles.Why concrete is an important engineering material, a large numble of other composite systems are based on particle reinforcement. Particulate composites refer specifically to systems with relatively large size dispersed particles(at least several micrometers in diameter),and the particles are in relatively high concentration(greater than 25 and frequently between 60 and 90) of small diameter oxide particles. The oxide particles strengthen the metal by serving as obstacles to dislocation motion.2.7.2 like so many accomplishments of human beings, those fiberreinforced composites imitate nature. Common wood is such a composite, which serves as an excellent structural material. In fact, the weight of wood used each year in the Uited Sates exceeds the combined total for steel and concrete. We find two categories , softwoods and hardwoods. These are relative terms, although softwoods generally have lower strengths. The fundamental difference between the categories is their seasonal nature. Softwoods are “evergreens” with needlelike leaves and exposed seeds. Hardwoods are deciduous( i.e., lose their leaves annually)with covered seeds( i.e.,nuts)The microstructure of wood illustrates its commonality with the human-made composites. The dominant feature of the microstructure is the large number of tubelike cells oriented vertically. These longgitudinal cells are aligned with the vertical axis of the tree. There are some radial cells perpendicular to the longitudinal ones. As the name implies, the radial cells extend from the center of the tree trunk out radically toward the surface. The longitudinal cells carry sap and other fluids critical to the growth process. Early seaon cells are of larger diameter than later season cells. This growth pattern leads to the characteristic “ring structure”which indicates the tree’s age. The radial cells store foodfor the growing tree. The cell walls are composed of cellulose. The strength of the cells in the longitudinal direction is a function of fiber alignment in that direction. The cells are held together by a matrix of lignin and hemicellulose. Lignin is a phenol propane network ploymer, and hemicellulose is ploymeric cellulose with a relatively low degree of ploymerization.Related to this ,the dimensions as well as the proper ties of wood vary significantly with atmospheric moisture levels. Care will be required in specifying the atmospheric conditions for which mechanical property data apply.2.7.1 let us begin by concentrating on fiberglass, or glass fiber reinforced ploymer. This is a classic example of a modern composite system. A typical fracture surface of a composite shows fibers embedded in the ploymeric matrix, such fibers may have different composition since each is the result of substantial development that has led to optimal suitability for specific applications. For example, the most generally used glass fiber composition is E glass, in which E stands for its especially low electrical conductivity and its attractiveness as a dielectric. Its popularity in structural composites is related to the chemical durability of the borosilicatecomposition. We should note that optimal strengh is achieved by the aligned, continuous fiber reinforcement. In other words, the strength is highly anisotropic.The fiber reinforced composites include some of the most sophisticated materials developed by man for some of the most demanding engineering applications. Important examples include boron reinforced aluminum, graphite epoxy, and al reinforced aluminum. Metal fibers are frequently small diameter wires. Especially high strength reinforcement come from “whiskers” which are small, single crystal fibers that can be grown with a nearly perfect crystalline structure. Unfortunately , whiskers cannot be grown as continuous filaments in the manner of glass fibers or metal wires.2.5polymerpolymers are chemical compounds that consist of long,chainlike molecules made up of multiple repeatinf units.The term polyner was coined in 1832 by the Swedish chemist Jins Jacob Berzelius from the Greek pols,or "many" and meros,or "parts."Polymers are also referred to as macromolecules,or "gaint molecules"-a term introduced by the German chemist Hermann Staudinger in 1992.Some gaint molecules occur maturally.Proteins ,for example ,are natural polymers of amino acids that make up muchof the structural material of animals;and the polymers deoxyribonucleic acid(DNA) and ribonucleic acid(RNA) are liner strands of nucleotides that define the genetic make up of living organisms.Other examples of natural polmers are silk ,wool.natural rubber,cellulose ,and shellac.There materials have been known and exploited since ancient times.Indeed,people in what is now Switzerland cultivates flax,a source of polymeric cellulose fibres,during the Neolithic Period,or New Stone Age,some 10 000 years ,while other ancients collected proteinaceous wool fibers from sheep and silk fibers from silkworms.About five millennia ago,tanners produced leather through the cross linking of proteins by gallic acid forming the basis of the oldest industry in continuous production.Even embalming,the art for which ancient Egypt is famous is based on the condensation and cross linking of proteins with form aldehyde.Early developments in polymer technology,taking place in the 19th century,involved the conversion of natural polymers to more useful products-for example,the conversion of cellulose,obtained from cotton or wood,into celluloid,one of the first plastic.Before the 1930s only a small number of synthetically produced polymers were availablecommercially,but after that period and especially after World War II,synthetic compounds came to dominance.Derived principally from the refining of petroleum and natural gas,synthetic polymers are made into the plastics,rubbers,man-made fibres,adhesives,and surface coatings that have become so ubiquitous in modern life.As an important materials,the polymers are available in a wide variety of commercial forms:fibers,thin films and sheets,foams and in bulk.A common synonym for polymers is "plastic",a name derived from the deformability associated with the fabrication of most polymeric products.To some critics,"plastic" is a synonym for modern culture.Accurate or not,it represents the impact that this complex family of engineering materials has had on our society.Polymers are distinguished from our previous types of materials by chemistry.Metal,ceramics.and glasses are inorganic materials.The polymers discussed here are organic.The student should not be concerned about a lack of background in organic chenistry.This passage is intended to provide any of the fundamentals of organic chemistry needed to appreciate the unique nature of polymeric materials.We begin our discussion of polymers by investigating polymerization,theprocess by which long chain or network molecules are made from relatively small organic molecules.The structural features of the resulting polymers are rather unique compared to the inorganic materials.Ingeneral,the ,elting point and rigidity of polymers increase with the extent of plymerization and with the complexity of the molecular structure.We shall find that polymers fall into one of two main categories.Thermoplastic polymers are materials that become less rigid upon heating,and thermosetting polymers become more rigid upon heating.For both categories,it is important to appreciate the roles played by additives,which provide important features such as color and resistance to combustion.As with ceramics and glasses,we shall discuss important mechanical and optical properties of polymers.Mechanically,polymers exhibit behavior associated with their long chain molecular structure.Examples include viscoelastic and elastomeric deformation .Optical properties such as transparency and color,so important in ceramic technology,are also significant in the selection of polymers.2.5.1 PolymerizationThe term polymer simply means "many mers" where mer is thebuilding block of the long chain or network molecule.There are two distinct ways in which a poly merization reaction can take place.Chain growth(also known as addition polymerization)involves a rapid "chain reaction" of chemically activated monomers.Step growth(also known as condensation polymerization)involves individual chemical reactions between pairs of reactive monomers and is a much slower process.In either case,the critical feature of a monomer,which permits it to join with similar molecules and form a polymer,is the presence of reactive sites,that is double bonds(chain growth) or reactive functional groups (step geowth).Each covalent bond is a pair of electrins shared between adjacent atoms.The double bond is two such pairs.The chain growth reaction converts the double bond in the monomer to a single bond in the mer.The remaining two electrons become parts of the single bonds joining adjacent mers.2.5.2 Thermal Plastic PolymersThermoplastic polymers become soft and deformable upon heating.This is characteristic of linear polymeric molecules.The high temperature plasticity is due to the ability of the molecules to slide past one another.This is anotherexample of a thermally activated,or Arrhenius process.In this sence ,thermoplastic materials are similar to metals that gain ductility at high temperatures.The key distinction between thermoplastics and metals is what we mean by "high" temperatures.The secondary bonding,which must be overcome to deform thermoplastics,may allow substantial deformation around 100,whereas metallic bonding generally restricts creep deformation to temperature closer to 1000 in typical alloys.It should be noted that,as with metals,the ductility of thermoplastic polymers is lost upon cooling.2.5.3 Thermal Setting PolymersThermosetting polymers are the opposite of the thermoplastics.They become hard and rigid upon heating.Unlike thermoplastic polymers,this phenomenon is not lost upon cooling.This is characteristic of network molecular structures formed by the step growth mechanism.The chemical reaction "steps" are enhanced by higher temperatures and are irreversible,that is,the polymerization remains upon cooling.In fabricating thermosetting products,they can be removed from the mold at the fabrication temperature (typically 200 to 300).By contrast,thermoplastics must be cooled in themokd to prevent distortion.It might also be noted that network copolymers can be formed similar to be the block and graft copolymers.The network copolymer will result from polymerization of a combination of more than one species of polyfunctional monomers.2.5.4 AdditivesCopolymers and blends were discussed above as analogs of metallic alloys.There are aeveral other alloylike additives that traditionally have been used in polymer technology to provide specific characteristics to the polymers .A plasticizer is added to soften a polymer.This addition is essentially blending with a low molecular weight (approximately 300 amu) polymer.A filler ,on the other hand .is added to strengthen a polymer primarily by restricting chain mobility.it also provides dimensional stability and reduced cost.Relatively inert materials are used.Examples include shortchanger cellulose (and organic filler) and asbestos (and inorganic filler).Roughly one third of the typical automobile tire is a filler (i.e.,carbon black).Reinforcements such as glass fibers are also categorized as additives but produce suchfundamentally different materials (e.g.,fiberglass) that they are properly discussed later on composites.Stabilizers are additives used to reduce polymer degradtion.They represent a complex set of materials because of the large variety of degradation mechanisms(oxidation,thermal,and ultraviolet).As an example,polyisoprene can absorb up to 15% oxygen at room temperature with its elastic properties being destoryed by the first 1%.Natural rubber latex contains complex phenol groups that retard the room temperature oxidation reactions.However,these naturally occurring antioxidants are not effective at elevated temperatures.Therefore ,additional stabilizers(e.g.,other phenols,amines,sulphur compounds,etc.)are added to rubber intended for tire applications.Flame retardant are added to reduce the inherent combustibility of certain polymers such as bustion is simply the reaction of a hydrocarbon with oxygen accompanied by substantial heat evolution.Many polymeric hydrocarbons exhibit combustibility.Others,such as polyvinylchloride(PVC),donot.The resistance of PVC to combustion appears to come from the evolution of the chlorine atoms from the polymeric chaim.These halogens hinder the process of combustion by terminating free radical chain reactions.Additives that provide this function for halogen free polymers include chlorine,bromine,and phosphorus containing reactants.Colorant are additions to provide color to a polymer where appearance is a factor in materials selection.Two types of colorants are used,pigments and dyes.A pigment is an insoluble,colored material added in powered form.Typical examples are crystalline ceramics such as titanium oxide and aluminum silicate,although organic pigments are availble.Dyes are soluble,organic colorants that can provide transparent colors.2.5.5 Viscoelastic DeformationAt relatively low temperature,polymers are rigid solids and deform elastically.At relatively high temperatures,they are liquidlike and deform viscously.The boundary between elastic and viscous behavior is again known as the glass transition temperature,Tg.However,the variation in polymer deformation with temperature is not demonstrated in the sameway.For glassws,the variation in viscosity was plotted against temperature.For polymers,the modulus of elasticity is plotted instead of viscosity.There is a drastic and complicated drop in modulis with temperature for a typical,commercial thermoplastic with approxinately 50% crystallinity.THe magnitude of the drop is illustrated by the use of a logarithmic scale for modulus.At "low" temperatures (well below Tg),a rigid modulus occurs corresponding to mechanical behavior reminiscent of metals and ceramics.However,the substantial component of secondary bonding in the polymers cause the modulus for these materials to be substantially lower than the ones found for metals and ceramics,which were fully bonded by primary chemical bonds (metallic,ionic,and covalent).In the glass transition temperature (Tg) range,the modulus drops precipitously and the mechanical behavior is leathery.The polymer can be extensively deformed and slowly returns to itTys original shape upon stress removal.Just above Tg,a rubbery plateau is observed.In this region,extensive deformation is possible with rapid spring back to the original shape when stress is removed.These last two regions(leathery and rubbery) extend our understanding of elastic deformation.Sometimes the elastic deformation meant a relatively small strain directlyproporyional to applied stress.For polymers,extensive,non-linear deformationcan be fully recovered and is ,by definition,elastic.This concept will be explored shortly when we discuss elastomers,those polymers with predominant rubbery region.2.5.6 ElastomersTypical linear polymers exhibits a rubbery deformation region.For certain polymers known as elastomers,the rubbery plateau is pronounced and establishes the normal room temperature behavior of these materials.(For these materials,the glass transition temperature is below room temperture.)This subgroup of thermoplastic polymers includes the natural and synthetic rubbers (such as polyisoprene).These materials provide a dramatic example of the uncoiling of a linear polymer.As a practical matter,the complete uncoiling of the molecule is not achieved,but huge elastic strains do occur.The stress-strain curve for the elastic deformation of an elastomer shows dramatic contrast to the stress-strain curve for a common metal.In that case,the elastic modulus was constant throughout the elastic region (stress was directly proportional to strain).While the clastic modulus (slope of thestress-strain curve) increases with increasing strain.For low strains,the modulus is low corresponding to the small forces needed to overcome secondary bonding and to uncoil the molecules.For high strains,the modulus rises sharply,indicating the greater force needed to stretch the primary bonds along themolecular "backbone".In both region,however,there is a significant componrnt of secondary bonding involved in the deformation mechanism,and the moduli are much lower than those for common metals and ceramics.Tabulated values of moduli for elastomers are generally for the low strain region in which the materials are primarily used.Finally,it is important to emphasize that we are talking about elastic or temporary deformation.The uncoiled polymer molecules of an elastomer recoil to their original length upon removal of stress.2.5.7 Stress RelaxationFor metals and ceramics,we found creep deformation to be an important phenomenon at high temperatures (greater than one half the absolute melting point).A similar phenomenon,termed stress relaxation,occurs in polymers.This is perhaps moresignificant to polymers.Because of their loe melting points,stress relaxation can occur at room temperature.A familar example is the rubber band,understress for a long period of time,which does not snap back to its original size upon stress removal.2.4（88）Chemical substitutions in the BaTio3 structure can alter a number of ferro electric properties.For example,BaTio3 exhibits a large peak in dielectric constant near the Curie point-a property that is undesirable for stable capactior applications.This problem may be addressed by the substitution of lead (**) for (**),which increases the Curie point;by the substitutionof strontium,which lowers the Curie point;or by substituting Ba with calcium,which broadens the temperature range at which the peak occurs.Barium titanate can be produced by mixing and firing barium carbonate and titanium dioxide,but liquid-mix techniques are increasingly used in order to achieve better mixing,precise control of the barium titanium ratio,high purity,and submicrometre particle size.Processing of the resulting powder varies according to whether the capacitor isto be of the disk or multilayer type.Disks are dry pressed or punched from tape and then fired at temperatures between 1250 and 1350.Silver-paste screen printed electrodes are bonded to the surfaces at 750.Leads are soldered to the electrodes,and the disks are epoxy coated or wax impregnated for encapsulation.The capacitance of cermic disk capacitors can be increased by using thinner capacitors;unfortunately,fragility result.Multilayer capacitors overcome this problem by interleaving dielectric and electrode layers.The electrode layers are usually palladium or a palladium-silver alloy.These metals have a melting point that is higher than the sintering temperature of the ceramic,allowing the two materials to be cofired.By connecting alternate layers in paralled,large capacitance can be realized with the MLC.The dielectric layers are processed by tape casting or doctor blading and then yer thickness as small as 5 micrometres have been achieved.Finished "build" of dielectric and electrode layers are then diced into cubes and cofired.MLCs have the advantages of small size,low cost ,and good mounting on circuit boards.They are increasingly used in palce of disk capacitors in most electronic circuitry.Where monolithic units are still。
材料科学与工程-专业英语-Unit--Classification-of-Materials译文
材料科学与工程-专业英语-Unit--Classification-of-Ma terials译文————————————————————————————————作者：————————————————————————————————日期：Classification of Materials（材料分类）Solid materials have been conveniently grouped into three basic classifications: metals, 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 three other groups of important engineering materials—composites, semiconductors, and biomaterials.译文：固体材料被便利的分为三个基本的类型：金属，陶瓷和聚合物。
这个分类是首先基于化学组成和原子结构来分的，大多数材料落在明显的一个类别里面，尽管有许多中间品。
除此之外，有三类其他重要的工程材料－复合材料，半导体材料和生物材料。
Composites consist of combinations of two or more different materials, whereas semiconductors are utilized because of their unusual electrical characteristics; biomaterials are implanted into the human body. A brief explanation of the material types and representative characteristics is offered next.译文：复合材料由两种或者两种以上不同的材料组成，然而半导体由于它们非同寻常的电学性质而得到使用；生物材料被移植进入人类的身体中。
【精品】材料科学与工程(Materials Science and Engineering)专业英语讲义word版
材料科学与工程专业英语Materials Science and EngineeringUnit1Materials Science and EngineeringMaterials are properly more deep-seated in our culture than most of us realize. 材料可能比我们大部分人所意识到的更加深入地存在于我们的文化当中。
Transportation, housing, clothing, communication, recreation and food production－virtually every segment of our lives is influenced to one degree or another by materials.运输、住房、衣饰、通讯、娱乐，还有食品生产——实际上我们日常生活的每个部分都或多或少地受到材料的影响。
Historically, the development and advancement of societies have been int imately tied to the members’ abilities to produce and manipulate materials to fill their needs. 从历史上看，社会的发展和进步已经与社会成员生产和利用材料来满足自身需求的能力紧密地联系在一起。
In fact, early civilizations have been designated by the level of their materials development.事实上，早期文明是以当时材料的发展水平来命名的。
（也就是石器时代，青铜器时代）The earliest humans has access to only a very limited number of materials, those that occur naturally stone, wood, clay, skins, and so on. 最早的人类只能利用非常有限数量的材料，象那些自然界的石头，木头，黏土和毛皮等等。
MaterialScienceengineering材料科学与工程英文课件
magnetic behavior
Ceramic Objects
3. POLYMERS
A polymer is a large molecule (macromolecule) composed of repeating structural units typically connected by covalent chemical bonds
(distinguishing feature) in terms of the kind and magnitude of response to a specific imposed stimulus Six categories of properties -> mechanical, electrical, thermal, magnetic, optical, and deteriorative
Polymer Objects
COMPOSITES
Composites are engineered materials made from two or more constituent materials with significantly different physical or chemical properties, which remain separate and distinct on a macroscopic level within the finished structure
Material Science & Engineering
材料科学与工程专业英语课件
材料科学与工程专业英语课件
材料科学与工程专业的英语课件通常涵盖材料科学的基本理论、工程应用以及相关领域的最新进展。
课件内容可能涉及材料分类、
性能、加工工艺、测试方法等方面。
在教学中，课件可能会包括各
种图表、数据、案例分析等，以便帮助学生更好地理解和应用所学
知识。
从基础知识的角度来看，英语课件可能会介绍材料的原子结构、晶体结构、缺陷理论等基本概念，并通过英文文献、案例分析等方
式展示相关知识点。
在工程应用方面，课件可能会涉及材料的设计、选择、性能优化等内容，以及材料在航空航天、汽车制造、能源领
域等工程中的应用。
此外，课件可能还会介绍材料科学与工程领域的最新研究成果、前沿技术和发展趋势，以帮助学生了解行业动态，培养他们的创新
意识和解决问题的能力。
总之，材料科学与工程专业的英语课件应该全面覆盖材料科学
与工程领域的基础知识、工程应用和最新研究成果，以促进学生对
该领域的全面理解和应用能力的培养。
材料科学与工程专业英语课程教学大纲
专业英语课程教学大纲课程名称：专业英语课程编号：16118231学时/学分：24/1.5开课学期：6适用专业：材料科学与工程专业课程类型：院系选修课一、课程说明本课程是材料科学与工程专业的一门院系选修课。
专业英语是大学英语的后续课程，通过本课程的学习，同学们应该大致了解专业英语的文章的结构、词汇、写作方法及其与公共英语的异同点。
掌握材料专业常用的英语词汇，能较顺利的阅读、理解和翻译有关的科技英文文献和资料并掌握英文论文的书写格式及英文论文摘要的写作技巧，从而使同学们进一步提高英语能力，并能在今后的生产实践中有意识地利用所学知识，通过阅读最新的专业英语文献，能跟踪学科的发展动态，同时能与外国专家进行交流，为从事创新性的工作打下基础。
二、课程对毕业要求的支撑毕业要求10沟通：能够就本专业复杂工程问题与业界同行及社会公众进行有效沟通和交流，包括撰写报告和设计文稿、陈述发言、清晰表达或回应指令。
并具备一定的国际视野，能够在跨文化背景下进行沟通和交流。
指标点10.2：具备一定的国际视野，能够在跨文化背景下进行沟通和交流。
三、课程的教学目标1.掌握材料科学专业要求的基本专业英语词汇以及阅读、翻译、写作的技巧和方法。
2.能够理解阅读、翻译、写作对材料科学研究的意义以及培养专业学习兴趣，了解文化差异。
3.具备运用英语结合实际在涉外交际的日常活动和业务活动中进行简单的口头和书面交流能力。
四、课程基本内容和学时安排PartⅠIntroduction to materials science and engineering（10学时）知识点：Materials science and engineering(2学时)，Classification of materials(2学时)，Atomic structure of materials(2学时)，Physical and chemical properties of materials(2学时)，Mechanical properties of materials(2学时)；重点：Classification of materials，Mechanical properties of materials。
材料科学与工程专业英语2【手工输入,按章节】
Composite materials复合材料Ferroconcrete钢筋混凝土Steel reinforcement钢筋Civil engineering土木工程Polymeric materials聚合物材料Structural properties结构性能Tailor structure performance调整结构Thermal expansion热膨胀Fatigue resistance耐疲劳Science efforts科研工作Comprehension综合理解Optimization最佳化Structural composite materials结构复合材料Component部件Economic经济上State of the art技术水平Satisfy specific requite满足特殊需求Thermoplastic based composite热塑性塑料基复合材料Composites based on Natural occurring materials天然存在材料为基体的复合材料Resin树脂Cost-efficient合算Biomedical生物医学Concurrent engineering methodology并存的工程方法论Natural tissues天然组织College of material science and engineering材料科学与工程学院Cross-disciplinary strategies交叉学科策略National institute for advanced interdisciplinary research国家先进跨学科研究院Combining element综合元素Tissue engineering组织工程Trend趋势Quality assurance质量保证Specific functional properties功能特性The principal requirement最主要的要求Filler size填料大小Surface chemical nature表面化学特性Magnetic-elastic磁致弹性Significantly enhance明显提高Elasto-dynamic response弹性动力学响应Atoms原子Electrons电子Mature manufacturing technology成熟加工技术Set at design level处于设计水平Expectation期望Sensor传感器Actuators调节器Organ器官Artificial prosthesis人造假肢Muscle肌肉Cartilage软骨Soft tissue软组织Composite structure复合结构Biohybrid technology生物杂化技术Culture cells培养细胞Delivery vehicle运载工具Polymeric biodegradable scaffold可降解的聚合物支架纳米材料Nanostructured materials纳米材料Categories种类Chemical composition化学组成The arrangement of the atoms原子排列Atomic structure原子结构Solid state physics固体物理Inert gas惰性气体Condensation冷凝Amorphous无固定形状的Precipitation沉降Crystalline结晶Devices器件装备Multilayer quantum多层量子Nanometer-sized纳米尺寸Bulk块状Ion implantation离子植入Laser beam激光束Supersaturated liquid饱和液体Atomic structure of solid surface固体表面的原子结构Hardness硬的Modify修改修饰Corrosion resistance抗腐蚀Wear resistance耐磨损Protective coating保护层Subgroup分枝Free surface自由表面Pattern模型Lithograph光蚀刻Local probes局部探测Near-field近场Focused聚焦的Beams电流能量Integrated circuit集成电路Single electron transistor单电子晶体管Building blocks构筑模型Gels胶体Supersaturated solid solutions过饱和固溶体Nano-length scale纳米尺度Implanted materials植入材料Quenching淬火Annealing退火Assembled装配Incoherent非共格Coherent interface共格晶面Heterogeneous非均质的Grain boundaries晶界Inherently天生的，固有的Synonymous同义的Exclusively专有的，表征Concept概念Industrial society工业社会Triggered引发Technological revolution科技发展Steam engine蒸汽机Initiated开创Industrial era工业时代Silicon technology硅技术Phase阶段Embryonic胚胎Intergration集成Illustrate说明Chemical systems化学物系Monomer单体Block模板Backbone主链Organism有机体Life science生命科学Macroscopic design宏观设计Molecular application of synthetic materials合成材料的结构应用Reshuffle重组Buzz Word术语Phenomena现象Scientific environment科学环境Microscopy显微技术Determine确定Characterize表征Architecture结构Fullerenes富勒烯Nanotube纳米管Dendritic枝状Hyperbranched超支化Promising希望Milestone里程碑Dendrimers枝状单体Multifunctional macromolecular多功能大分子Non-covalent非共价Covalent compound共价化合物Ionic compound离子化合物Organic compound有机化合物Supramolecular超分子Mimicking模拟Potential关键Sustainable民用Modify改变Concept of life生活观念Thorough彻底Chemical industry化学工业Merger合并Fusion融合Life cycle生命周期S-curve S曲线Cracker裂化装置Bulk polymer本体聚合物Synergy协同作用Solution provider决策者Principal原理Spin-off company派生公司Pronounced明确的Polymeric materials高分子材料Co-operation合作Venture capital风险投资Entrepreneurial spirit企业家精神Crucial至关重要Capacitor电容器Water purification systems水纯化装置Solid-solubility固熔度Electronegativity电负性Chemical formula化学式Stainless steels不锈钢Transition metal过渡金属Copolymer共聚物Homopolymer均聚物Cells in parallel并联Cells in series串联Inorganic nomatallic material无机非金属Wavelength波长Dielectric constant介电常数Adverse effect副作用Fatigue resistance抗疲劳性Defect缺陷Photovoltaic cell光生伏打灯Biomimetic仿生Uniform均一的Dispersion分散Short circuit短路Battery shot电池短路Open circuit开路Environmental friendly环境友好Interdisciplinary各学科间的Mechanical机械的、力学的Magnetic磁力的Optical视觉的Deteriorative变化的Van der waals bonds范德瓦耳斯力TEM电子透射显微镜。
材料科学导论英文阅读
Chapter 1 An Overview第一章概述1.1 Introduction1.1介绍Materials are the matter of the universe. These substances have properties that make them useful in structures, machines, devices, products, and systems. The term properties describe behavior of materials when subjected to some external force or condition. For example, the tensile strength of a metal is a measure of the material's resistance to a pulling force. The Family of Materials consists of four main groups of materials: Metals (e.g., steel), Polymers (e.g., plastics), Ceramics (e.g., porcelain), and Composites (e.g., glass-reinforced plastics). The materials in each group have similar properties and/or structures, as will be described later.材料是宇宙的物质。
这些物质的特性使其有用的结构、机器设备、产品和系统。
这个术语属性描述材料的行为时,受到一些外部力量或状态。
例如,抗拉强度的金属是测量的材料抵抗了拉力。
这个家庭的材料由四个主要群体的材料:金属(如钢)、高分子材料(例如:塑料)、陶瓷(如瓷),复合材料(例如,增强塑料)。
材料科学与工程专业英语
Microstructure and properties of Mg–5.6%Sn–4.4%Zn–2.1%Al alloyS.Harosh Æler ÆG.Levi ÆM.BambergerReceived:26April 2007/Accepted:25July 2007/Published online:6September 2007ÓSpringer Science+Business Media,LLC 2007Abstract In a previous study,Mg–Sn–Zn-based alloys showed insufficient structural stability at elevated tempera-tures.In order to improve the castability and corrosion resistance 2.1%wt Al was added to the Mg–5.6%Sn–4.4%Zn base alloy.At the as-cast condition,SEM micrographs indicate a very fine microstructure (Dendritic Arm Spac-ing—DAS—smaller than 17l m).The study focuses on precipitation hardening,phase formation and structural stability,during the aging of solution treated samples at elevated temperatures.After solution treatment and aging at 225°C,Vickers hardness measurements show that this alloy maintains a constant increase of 30%in hardness for periods of up to 32days.EDS (SEM &STEM),XRD,and Auger characterization methods were applied to identify the phases presented in the alloy.There is no evidence for the presence of the deleterious c -Al 12Mg 17phase.SAXS measurement and STEM micrographs reveal very fine precipitations (less than 100nm)after 32days of aging,along with homogenously distributed larger precipitations (up to 500nm).IntroductionMagnesium alloys are known for their lightweight,high-specific stiffness,and very good castability and workabil-ity.Therefore,due to the demand for weight reduction of automotive components,the use of Mg alloys has signifi-cantly increased in recent years.A commercial alloy,suchas AZ91,contains high amounts of Al and some Zn.Al improves the castability,corrosion resistance,and strength at room temperature,however,this alloy exhibits poor creep resistance at elevated temperatures [1–3].The main reason for the poor creep resistance is the precipitation of the c -Mg 17Al 12phase at grain boundaries.In order to exploit the positive effect of Al,while avoiding its harmful influence at elevated temperatures,it was decided to reduce the amount of Al to 2wt%.Based on previous research [4,5],the main alloying elements were chosen to be Zn and Sn.Zn has several benefits in Mg based alloys [6,7].It increases the creep resistance,and forms several stable intermetallic phases with Mg.At the eutectic temperature,6.2%wt of Zn can be dissolved into Mg [8].At room temperature,the maximum solubility drops to 2%wt.In a similar way,Mg can dissolve 14.6%wt Sn at the eutectic temperature [8].Sn can form stable Mg 2Sn particles.During the aging of an Mg–Sn–Zn based alloy,firstly semi-coherent MgZn 2particles precipitate,which later transform into an incoherent MgZn phase,and secondly Mg 2Sn precipitates are formed [5].The precipi-tation mechanism is diffusion controlled.The precipitates are uniformly distributed in the Mg-matrix with two mor-phologies:needle-and plate–like shapes [4,5].However,limited structural stability during aging at 175°C of the alloys investigated in [4,5]was found,due to characteristic rapid precipitation.The main goal of the current study was to investigate microstructural stability of the alloy Mg–Sn–Zn–Al,com-pared to the base alloy studied earlier:Mg–3.8%Sn–4.5%Zn.The investigated alloy was characterized in the as-cast,solution treated state,and after aging and exposure to 225°C for up to 32days.The precipitation hardening was studied by Vickers hardness measurements and the microstructure by XRD,SEM,STEM,SAXS,DSC andS.Harosh Áler ÁG.Levi ÁM.Bamberger (&)Department of Material Engineering,Technion IIT,Haifa 32000,Israele-mail:mtrbam@tx.technion.ac.ilJ Mater Sci (2007)42:9983–9989DOI 10.1007/s10853-007-2059-yAuger spectroscopy.In order tofind the controlling mechanism in each precipitation stage,the activation energy of the process was calculated.Material and experimental procedureMelting and castingTable1lists the composition of the alloy investigated in this research;Pure Magnesium of99.98%and aluminum of 99.95%were melted in a cemented graphite crucible under protective atmosphere of60cc/min CHF134A+1L/min CO2gas mixture.When the magnesium and aluminum were completely melted,99.8%pure zinc and99.95%pure Sn were added into the melt at about720°C.After20min, the melt was poured at a temperature of720°C into a steel disc shaped mold of60mm in diameter and9mm thick. Solution treatmentSlices from the as-cast alloys were cut and encapsulated in quartz ampoules under400mm Hg Argon atmosphere,to prevent oxidation during solution treatment.The solution treatment was conducted in a Lindberg resistance furnace. This treatment included fast heating to350°C,holding for 48h,and slow heating at a rate of1°C per hour up to 450°C and holding at that temperature for additional96h. Finally the samples were quenched into water.This solution treatment is aimed to ensure complete dissolution of the alloying elements in the a-Mg matrix without any grain boundary melting.The solution treat-ment temperature was based on thermodynamic calculations using the Thermo-Calc software package. Precipitation hardeningSolution treated samples(10·10·5mm3)were put into a molten salt bath(sodium nitrate50%and potassium nitrate50%)at225°C for different time periods up to 32days.The molten salt was stirred and temperature controlled to ensure uniform and stable temperature of the salt during the experiments.For the purpose offinding the activation energy in the investigated alloy,aging for2h at different temperatures ranging from150°C to275°C was carried out.At the end of treatment the samples were quenched in water.Exposure to elevated temperaturesSamples(10·10·5mm3)in the as-cast state were put into the molten salt bath at225°C for different time periods up to32days.At the end of treatment the samples were quenched in water.Characterization and measurementsSpecimens for optical and electron microscopy were pol-ished with a320–1200mesh papers andfinally with an oil-based suspension of0.05l m alumina.The samples’microstructure,morphology and chemistry were investi-gated by SEM,XRD,EDS,Auger,and SAXS.TEM investigation was also carried out on samples20nm thick in the center(after polishing,dimpling and PIPS).Micro-hardness measurements were conducted using the Vickers method(1kg and100g loads),in order to monitor the precipitation strengthening process.DSC scans of samples in the as-cast state were taken for acquiring thermodynamic data and were compared with the calculated results. ResultsAs-cast stateSEM micrograph taken from thefirst third of the speci-mens,perpendicular to the solidification direction of the investigated alloy is shown in Fig.1.The microstructure of the as-cast state consists of a dendritic a-Mg matrix(dark phase)with thick bright boundaries reflecting the high concentration of alloying elements at grain boundaries.Similar coring effect hasTable1The chemical composition of the investigated alloy(deter-mined by DIRATS Lab USA)Mg Sn Zn Al %Wt87.9 5.6 4.42.1Fig.1SEM micrograph of the investigated alloy in as-cast conditionbeen previously shown[4,5].The chemical composition (EDS measurements)of a-Mg phase and the gray area neargrain boundaries are given in Table2.This alloy shows a veryfine morphology with DAS of16.6±3.5l m.The alloy microstructure contains an Mg2Sn phase and eutectic a-Mg+Mg32(Al,Zn)49phase,which was verified by XRD(shown in Fig.2)and TEM electron diffraction given in Fig.3,as well compositional analysis utilizing STEM+EDS(Table3).The presence of c-Mg17Al12could not be proven either by elements mapping by EDS,Auger analysis or by XRD.Thermodynamic data of the investigated alloy was found by DSC scans at a heating rate of10°C/min(shown in Fig.4).The melting temperature of each phase, noticeable by its characteristic endothermic peak,corre-sponds quite well with published data and Thermo-Calc calculations:348°C for the eutectic reaction,563°C of Mg2Sn and615°C is the liquidus temperature.The total enthalpy of melting is214.9J/g as against246.1J/g calcu-lated by Thermo-Calc software package.Table2Mean composition at grain boundaries and within the a-Mg matrix[%wt]a-Mg At grain boundariesMean Std Mean StdMg93.90.788.1 1.6Al 1.70.5 2.70.7Zn 1.50.2 3.4 1.3Sn 2.90.6 5.70.6 Fig.2X-ray diffraction spectra for the as-castcondition Fig.3Electron diffraction taken from zone axis[111]of Mg32(Al,Zn)49phase.The transmitted beam is marked X.The pattern of the cubic Mg32(Al,Zn)49precipitate(JCPDS19–29)isindexedFig.4DSC scan at as-cast condition Table3Chemical composition of Mg32(Al,Zn)49phase(%at)Mean stdMg40.20.3 Al16.20.3 Zn43.60.4Solution treatmentMost of the phases composing the alloy were dissolved into the a -Mg phase,and only a few (about 0.5%area)Mg 2Sn precipitations (size up to 5l m)remained after the solution treatment.XRD analysis and EDS measurements con-firmed that the only phases present after the solution treatment are a -Mg and Mg 2Sn.Precipitation hardeningSolution treated samples were aged at 225°C for different periods of time up to 32days.Figure 5a,b show the Vickers hardness for the complete aging period and for the first 48h,respectively.These values were taken using a 1kg load on the Vickers’hardness indenter.Repeating this experiment using a 100g load gave similar results.Based on the hardness (Fig.5a,b),it can be concluded that the investigated alloy is stable at elevated temperatures for at least 32days.The hardness values become constant after 24h of aging at 225°C,and overaging did not occur during the entire testing period.The constant hardness is about 67Hv (increase of 19.6%compared withtheFig.5Vickers hardness after aging at 225°C for (a )32days,(b )the first 50hFig.7STEM micrographs after (a )1day of aging,(b )32days of aging at 225°CFig.6SEM micrographs after aging at 225°C for:(a )1day;(b )32dayshardness of solution treated sample).Two hardness peaks are discernible—The first peak after 1h and the second after 24h.As shown before by HRTEM analysis [4,5],the first peak is correlated to the precipitation of the MgZn 2phase,whereas the second is correlated to the precipitation of the Mg 2Sn phase.Current EDS (in STEM)measure-ments are in accord with this precipitation sequence,but it could not be verified by electron diffraction due to the very small size of the precipitations (Figs.6and 7).STEM micrographs (Fig.7a–b)taken after aging reveal that the precipitates can be grouped into two populations—one less than *1l m and the other less than *100nm.SAXS results reveal that the smaller precipitates have either spherical or needle-like shape,and that in the initial stages of aging they are aligned with respect to the matrix.The aligned phenomenon can also be seen after 1day of aging in SEM (Fig.6a)and STEM (Fig.7a)micrographs.Based on [5,9]it can be assumed that the precipitates are MgZn 2.According to SEM micrographs (Fig.6a,b),these precipitates are uniformly distributed in the matrix without any change in the alloy’s microstructure during aging,besides loosing their alignment (compare Fig.6a,b).In addition,SAXS results show that after 4days of aging (the beginning of the constant hardness value of the alloys)the size of round particles (*48nm)hardly chan-ged with aging times.STEM bright field micrograph (Fig.7b)shows that some of the precipitates’size remained below 100nm.The dimensions of the needle-like precipitates are *250nm in length and *25nm in width (10:1ratio).The mean grain size of the investigated alloy after aging was 78.1±14.3l m.These findings confirm the assumption that the microstructure of the alloy is very stable,although the relatively high aging temperature,which explains the constant micro-hardness values.Activation energy for agingThe variation of hardness after 2h of aging at different temperatures is presented in Fig.8.Two hardness slopes are discernible.Assuming an Arrhenius type formulationfor the dependence of the hardness on the aging tempera-ture [10,11],the empirical activation energy for each hardness peak was calculated from the slopes in Fig.9a,b.The values are 5.7kJ/mol and 3.3kJ/mol,respectively.Exposure to elevated temperatureAs-cast samples were exposed to 225°C for different periods of time up to 32days.The hardness values (Fig.10)are stable at about 59Hv.SEM micrographs (Fig.11a,b)reveal very fine precipitates in the regions of high solutes content close to the grain boundaries.The fine precipitates show two morphologies,round and needle-like,similar to those in the aged samples.This fact indi-cates that the fine precipitates are the same as those found in the aged specimens,namely MgZn 2/MgZn and Mg 2Sn.DiscussionThe investigated alloy,Mg–5.6%Sn–4.4%Zn–2.1%Al has a fine microstructure:DAS of 17l m as against 44l minFig.8Vickers hardness values vesus temperature after 2h ofagingFig.9Calculating the empirical activation energy related to the (a )first peak (b )second peak of the hardness processthe basic alloy [4,5].Furthermore,after solution treatment and aging,the mean grain size was 78l m,which is smaller than that of typical gravity die cast Mg alloys [12].Solu-tion treatment at 450°C dissolved uniformly most of the as-cast phases.The precipitate distribution after aging (Fig.6)confirms this.The two hardness peaks found during aging correspond with two types of precipitates found in the Mg–Sn–Zn base alloy,namely the precipitation of MgZn 2followed by the precipitation of Mg 2Sn [4,5].This sequence resulted from the higher diffusion coefficient of Zn in Mg and the coherency between the MgZn 2and the Mg matrix.The MgZn 2coherency with the matrix is also reflected in the alignment of the precipitates during the earlier stages of aging (Figs.6a and 7a).SAXS measurements revealed that these particles are either round (mean size of *48nm)or plate-like (mean length of *250nm)throughout the complete test period of 32days.This explains the constant high hardness found in the addressed alloy as against rapid overaging observed in the Al-free base alloy.The different hardening mechanisms,i.e.,the two types of precipitates responsible for hardening,find their expression in the two distinct activation energies found at low and high temperatures.At low temperatures and after 2h of aging,only MgZn 2precipitates exist,hence the activation energy in this temperature range (5.7kJ/mole)corresponds to this type of precipitates.At higher tem-peratures,the precipitation of Mg 2Sn determines the hardness,hence its activation energy is 3.3kJ/mole.The value for the precipitation of MgZn 2is close to the one found for Mg–Ca–Zn [10]and ZA84Mg–alloy [12].Since the activation energy for bulk diffusion of Zn in Mg is 120kJ/mole and for Sn it is 150kJ/mole [13],it can be concluded that the precipitation is grain boundary diffu-sion-dependent rather than bulk diffusion dependent.The benefit of adding 2%wtAl is quite obvious;com-pared with the Al-free base alloy the Al addition seems to slow down the precipitation of MgZn 2and Mg 2Sn.Therefore,the hardness peaks in the investigated alloy took place after 1h and 24h,whereas for the basic alloy only the second peak was discernible after aging for 1h at 225°C,and overaging took place already after 16h [4].The slow precipitation can be attributed to the presence of Al at the precipitate/matrix interface or to the fact that the Al atoms dissolved in the a -Mg matrix serve as a diffusion barrier to the Sn and Zn atoms.The addition of Al,at the low level examined in the current study,resulted in Mg and Mg 32(Al,Zn)49eutectic rather than Mg and MgZn,which was found in Mg–Sn–Zn base alloy [5].This is in accord with the formation of s -Mg 32(Al,Zn)49in Mg–Zn–Al alloys with a Zn:Al ratio of about 2:1[12].The formation of the apparently more stable Mg 32(Al,Zn)49suppressed the formation of c -Al 12Mg 17,which soften at elevated temperatures and hence is deleterious for applications at elevated temperatures.Therefore,Mg–5.6%Sn–4.4%Zn–2.1%Al,which exhibits stable structure and mechanical (hardness)properties at 225°C,is a very promising Mg–alloy for high temperature applications.Conclusions •The investigated alloys show stable microstructure that is reflected in stable hardness values at 225°C for 32days.Fig.10Micro-hardness results during temperature exposure at 225°CFig.11SEM micrographs after exposure to 225°C for (a )1day;(b )32days•The eutectic is composed of Mg and Mg32(Al,Zn)49 rather than Mg and MgZn found in Mg–Sn–Zn alloys.•c-Mg17Al12phase does not form because Al is consumed by the Mg32(Al,Zn)49phase.•Al addition delayed the precipitation of MgZn2and Mg2Sn,in comparison with Al-free Mg–Sn–Zn alloys.•The investigated Mg–Zn–Sn–Al alloy is a promising candidate for future commercial applications at ele-vated temperatures.References1.Regev M,Rosen A,Bamberger M(1999)In:Froes FH,Ward-Close CM,Eliezer D,McCormick P(ed)Synthesis of lightweight metals III,TMS1632.Zhang Z,Couture A(1998)Scripta Mater39:453.Blum W,Zhang P,Watzinger B,Grossmann BV,HaldenwangerH(2001)Mater Sci Eng A319–321:7354.Cohen S,Goren-Muginstein GR,Abraham S,Dehm G,Bam-berger M(2004)In:Luo AA(ed)Mg Technology2004,TMS2004annual meeting,Charlotte,USA,14–18March2004, p3015.Cohen S,Goren-Muginstein G,Avraham S,Rashkova B,DehmG,Bamberger M(2005)Zeitschrift fu¨r Metasllkunde96:1081 6.Horie T,Iwahori H,Seno Y,Awano Y(2000)In:Kaplan HI,Hyrn JN,Clow BB(eds)Mg Technology2000,TMS2000 annual meeting,Nashville,USA,12–15March2000,p261 7.Maeng D,Kim T,Lee J,Hong S,Seo S,Chun B(2000)ScriptaMater43:3858.Massalski T(1992)Binary alloy phase diagrams,2nd edn.ASMInt9.Gorny A,Katsman A,Popov I,Bamberger M(2007)In:BealsRS,Lou AA,Neelameggham NR,Pekguleryuz MO(eds)Mg Technology2007,TMS2007annual meeting,Orlando,USA,26 February,1March2007,p30710.Reed-Hill RE,Abbaschian R(1992)Physical metallurgy princi-ples.PWS-KENT Publishing Co.,Boston,MA,USA,pp677–67811.Bamberger M,Levi G,Vander Sande JB(2006)Metall MaterTrans A37:48112.Wang Y,Guan S,Zeng X,Ding W(2006)Mater Sci EngA416:10913.Smithells CJ(1970)Metals reference book,5th edn。
材料科学与工程-专业英语-Unit-2-Classification-of-Materials译文
Classification of Materials（材料分类）Solid materials have been conveniently grouped into three basic classifications: metals, 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 three other groups of important engineering materials—composites, semiconductors, and biomaterials.译文：固体材料被便利的分为三个基本的类型：金属，陶瓷和聚合物。
这个分类是首先基于化学组成和原子结构来分的，大多数材料落在明显的一个类别里面，尽管有许多中间品。
除此之外，有三类其他重要的工程材料－复合材料，半导体材料和生物材料。
Composites consist of combinations of two or more different materials, whereas semiconductors are utilized because of their unusual electrical characteristics; biomaterials are implanted into the human body. A brief explanation of the material types and representative characteristics is offered next.译文：复合材料由两种或者两种以上不同的材料组成，然而半导体由于它们非同寻常的电学性质而得到使用；生物材料被移植进入人类的身体中。
材料科学与工程专业英语
1.Materials have always been important to the advance of civilization..P1 材料一直在（人类）文明的前进中起到重要的作用，所有的时代都以他们的名字来命名，从石器时代开始经历了铜器时代和铁器时代发展到现在，我们仍有大量的特制的材料去使用，我们的确是生活在一个材料的时代。
2.Metals and alloys generally have the characteristics of good electrical…….P4金属以及合计一般来说都有以下的一些特性：了好的导电和导热能力，相对高的强度，高刚度，延展性(塑性)以及成型性，和抗冲击性，他们对于结构件和受载荷件是特别的有用处的。
尽管纯金属很少被使用，然而把金属组合起来可以获得更好的性能组合，可以使需要的某一特定性能获得提高，这种金属组合称为合金。
3.Much of the information about the control of microstructure or phase structure……P25 相图，它可以方便的，简洁的去展示大多数的关于特定的合金系统的微观结构和相结构方面的控制信息，它也叫做平衡或者组分相图。
当(一种金属的)相发生转变时，许多的微观结构也会发展（变化），这个转变会会在温度被改变时（通常是在冷却时）的两相中。
（这种变化）可能包含了一种相向另外一种相的转变，或者是一种相的出现或者消失。
相图对于预测相的转变和最终的微观结构是很有帮助的，并且有平衡与非平衡的特性。
4.The first step in the determination of phase composition is to located the……P27 确定相图的组成成分的第一步就是要去找到在相图中的温度—成分点，对于单相区和双相区有不同的方法被使用。
如果是单相区，过程是很简单的：这个相的成分就和这个合金的总的成分相同。
材料科学与工程专业英语
材料科学与工程专业英语Material Science and Engineering Major English。
Material science and engineering is a multidisciplinary field that involves the study of the structure, properties, and performance of materials. It plays a crucial role in the development of new materials and technologies that are essential for various industries, including aerospace, automotive, electronics, and healthcare. As a material science and engineering major, it is important to have a strong command of English, as it is the primary language of communication in the global scientific community.One of the key aspects of studying material science and engineering in English is the ability to understand and communicate complex technical concepts. This includes being able to read and comprehend scientific papers, write research reports, and present findings at conferences. In addition, having a good grasp of English will also enable material science and engineering professionals to collaborate with colleagues from around the world, participate in international research projects, and contribute to the advancement of the field.Furthermore, being proficient in English is essential for accessing and understanding the latest developments in material science and engineering. Many of the most influential scientific journals and conferences are published in English, and a significant portion of the cutting-edge research in the field is conducted in English-speaking countries. By being able to read and understand these resources, material science and engineering students and professionals can stay up to date with the latest advancements and incorporate them into their own work.In addition to technical proficiency, strong English skills are also important for career advancement in material science and engineering. Many multinational companies and research institutions require employees to have a high level of English proficiency, particularly for positions that involve collaboration with international partners or clients. Moreover, being able to effectively communicate in English can open up opportunitiesfor material science and engineering professionals to work and study abroad, further expanding their knowledge and expertise in the field.To excel in material science and engineering, students should actively seek opportunities to improve their English skills. This may include taking English language courses, participating in language exchange programs, and practicing technical writing and presentation skills in English. Additionally, staying informed about the latest developments in the field through English-language resources such as scientific journals, conferences, and online forums can also help students develop their language proficiency and technical knowledge simultaneously.In conclusion, proficiency in English is essential for success in the field of material science and engineering. By mastering the language, students and professionals can effectively communicate complex technical concepts, stay informed about the latest developments in the field, and access global opportunities for collaboration and career advancement. Therefore, material science and engineering students should prioritize developing their English skills alongside their technical expertise to thrive in this dynamic and impactful field.。
材料专业英语文献选读
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The solid must achieve a certain minimum critical size before it is stable. Growth of the solid occurs as atoms from the liquid are attached to the tiny solid until no liquid remains.
together to produce a small region that
resembles the solid material.
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This small solid particle is called an embryo. The total change in free energy produced when the embryo forms is the sum of the decrease in volume free energy and the increase in surface free energy.
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We expect a material to solidify when the
liquid cools to just below the freezing
temperature because the energy associated with the crystalline structure of the solid is then less than the energy of the liquid.
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Only a few atoms must cluster together to produce a solid particle that has the required radius of curvature. Much less undercooling is required to achieve the critical size, so nucleation occurs more readily. Nucleation on impurity surfaces is known as heterogeneous nucleation. All engineering metals and alloys nucleate heterogeneously during solidification.
材料科学与工程专业英语-刘爱国主编
2.2虽然有色合金在当前工程设计中的应用大部分采用金属，有色金属合金中发挥我们的技术大和不可或缺的作用。
至于铁合金，非铁合金名单，当然是长期和复杂的。
至于铁合金，非铁合金名单，当然是长期和复杂的。
铝合金是最知名的低密度和耐腐蚀性。
导电性，易于制造，外观也引人注目的特色。
因为这些，世界的铝生产大约一倍，一近10年。
铝矿石储量大，铝可方便地回收利用。
镁合金具有更低的密度比铝作为一个结果，，航空航天等许多结构设计应用apper。
•铝是一种催化裂化物质，因此有很多支路系统，从而导致良好的延展性。
相比之下，镁是只有三个滑移系和特色脆性赛。
钛合金已成为第二次世界大战以来广泛使用。
在此之前，从被动的分离钛金属氧化物和氮化物的实用方法不详。
一旦形成，钛的反应工程，它的优势。
薄，顽强氧化物的形式在其表面涂层，使优良的耐腐蚀性能。
这种“钝化”将在后面详细讨论。
钛的合金，如铝，镁，铁是低于密度。
虽然越来越多的密度大于铝或毫克，钛合金有保留在温度适中的服务实力明显的优势，导致许多航空航天设计应用。
钛股份以特有的与领先的低塑性镁HCP结构。
不过，高温度bcc结构，可在室温稳定，如钒合金添加一定的温度。
铜合金具有优良性能的数目。
其优异的导电性，使铜合金为主要材料的电线。
其优良的热导率导致对散热器andheat热交换器中的应用。
优越的耐腐蚀性是展出海洋和其他腐蚀性环境。
thefcc结构有助于他们的韧性和成形性普遍较高。
其着色是经常用于建筑的外观。
铜合金广泛使用，导致通过历史的描述性词语有点困惑的集合。
这些合金的力学性能的竞争对手在他们变异的钢材。
高纯度铜是一个非常柔软的材料。
铍的2瓦特另外一个热处理后，产生立方体沉淀足以推动超过1000兆帕斯卡的拉伸强度。
镍合金与铜合金在许多共同之处。
我们已经使用的经典examp铜镍系统完整的固体溶解度é。
蒙乃尔是给予重量约为2:1镍铜合金比钛的商业名称。
这些都是解决硬化很好的例子。
材料科学与工程专业外语文章39页PPT
谢谢！
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材料科学与工程专业外语文章
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46、寓形宇内复几时，曷不委心任去 留。
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4得此生。
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49、勤学如春起之苗，不见其增，日 有所长 。
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50、环堵萧然，不蔽风日；短褐穿结 ，箪瓢 屡空， 晏如也 。
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26、要使整个人生都过得舒适、愉快，这是不可能的，因为人类必须具备一种能应付逆境的态度。——卢梭
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27、只有把抱怨环境的心情，化为上进的力量，才是成功的保证。——罗曼·罗兰
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28、知之者不如好之者，好之者不如乐之者。——孔子
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29、勇猛、大胆和坚定的决心能够抵得上武器的精良。——达·芬奇
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30、意志是一个强壮的盲人，倚靠在明眼的跛子肩上。——叔本华
材料科学与工程基础大纲(英文)
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3-2 Binary System Phase Diagrams
1、Binary Isomorphous System 2、Binary Eutectic System 3、Binary Peritectic System 4、Binary Equilibrium Diagrams Having Intermediate Phase or Compounds
•
Chapter 1 Crystallography
• 0-0 Introduction
• 0-1、Historical Perspective • 0-2、Materials Science and Engineering
• 0-3、Classification of Materials
• 0-4、Crystallography and Crystal Structures
Chapter 2
1、Vacancy Mechanisms
Diffusion
2-1 Diffusion Mechanisms
2、Interstitial Mechanisms
2-2 Macroscopic Theory of Diffusion
1、Steady-State Diffusion a、Fick`s First Law b、Example Problem 2、Nonsteady-State Diffusion a、Fick`s Second Law b、Example Problem
1-3 Crystallographic Directions
【专业英语】材料科学与工程
Part 1 Introduction to materials science and engineering
• Unit 1 Physical and chemical properties of materials
• Unit 2 Mechanical properties of materials
材料科学与工程专业英语
Unit 1 Physical and chemical properties of materials
• Physical properties are those that can be observed without changing the identity of the substance. The general properties of matter such as color, density, hardness, are examples of physical properties. Properties that describe how a substance changes into a completely different substance are called chemical properties. Flammability and corrosion/oxidation resistance are examples of chemical properties.
材料科学与工程专业英语
材料科学与工程专业英语
ห้องสมุดไป่ตู้
• In general, some of the more important physical and chemical properties from an engineering material standpoint include phase transformation temperatures, density, specific gravity, thermal conductivity, linear coefficient of thermal expansion, electrical conductivity and resistivity, magnetic permeability, and corrosion resistance, and so on. 磁导率
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However, graphite has an inherent limitation with a theoretical gravimetric capacity estimated at 370 mAh/g. For the purpose of improving the energy density of batteries, scientists have made great efforts to explore alternative anode materials with higher capacity.
Lithium ion batteries using the lithium transition metal oxide cathode and graphite anode have been the power sources for various mobile communication devices, portable electronic devices, and electric/hybrid vehicles.
oxidation–reduction reaction between graphene oxide and SnCl2•2H2O. The SnO2/graphene composite showed a superior rate capability and
cycling performance.
There are two electrochemical processes in the SnO2-based lithium ion batteries:
As the reaction (2) demonstrates, a volume change of 200–300% occurs during lithiation/delithiation process between Sn and Li4.4Sn. This reaction can generate a large internal stress, leading to cracking of electrode, loss of electrical contact, large initial irreversible capacity, and eventually quick fading of capacity.
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To overcome the internal stress problem, great attention has
been paid to nano-structured SnO2 and SnO2/carbon composite electrodes. Graphene, a monolayer of graphite, exhibits a number of intriguing unique properties such as high surface area of over
2600m2/g, large surface-to-volume ratio, high room temperature
(RT) carrier mobility, conductance quantization
Therefore, graphene has been regarded as an ideal carbon nanostructure which can be used to design high performance SnO2/carbon composite electrodes.
capacity could remain 570 mAh/g after 30 cycles at a current density of 50 mA/g.
Yao et al. [22] synthesized SnO2/graphene composite by direct oxidation of a Sn– graphene composite (which were prepared by coreduction of graphene oxide and Sn2+ with NaBH4) at 120 C in atmosphere. The obtained SnO2/graphene composite had a capacity of 765 mAh/g at the first cycle at a current density of 55 mA/g. Besides, Wang et al. prepared SnO2-graphene composite using a ternary self-assembly
专业英文文献选读
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A Stability electrode for lithium ion batteries
Carbon Volume 49, Issue 1, January 2011：133–139
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Introduction
of SnO2/graphene composite in these reports. In addition, more efforts are needed to improve the cycling performance of the composite.
In this paper, we prepared a SnO2/graphene composite through an
approach. The composite delivered a specific capacity of 625 mAh/g after 10 cycles at
a current density of 0.01 A/g.
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However, it is a pity that there are no studies about high rate performance
3
As a large band gap semiconductor, SnO2 has attracted a lot of attention
due to its relatively high theoretical reversible capacity (790 mAh/g), which is more than twice that of the currently used graphite.
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Up to date, there have been a few reports about the preparation of SnO2/graphene composite.
Paek et al. [2] synthesized a SnO2/graphene composite with three-dimensionally delaminated flexible structure by mechanical mixing SnO2 nanoparticles with graphene nanosheets. The as-prepared SnO2/graphene electrode material exhibited an enhanced cyclic performance and lithium storage capacity. As claimed, the charge
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