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首页 机械英语文章中英文对照(可编辑).doc

机械英语文章中英文对照(可编辑).doc

机械英语文章中英文对照(可编辑).doc

上传者: June妮妮 2018-07-12 评分 0 0 0 0 0 0 暂无简介 简介 举报

简介:本文档为《机械英语文章中英文对照(可编辑)doc》,可适用于工程科技领域,主题内容包含机械英语文章中英文对照(可编辑)机械英语文章中英文对照CeramicsandGlasses陶瓷和玻璃Aceramicisoftenbroadlyde符等。

机械英语文章中英文对照(可编辑)机械英语文章中英文对照CeramicsandGlasses陶瓷和玻璃AceramicisoftenbroadlydefinedasanyinorganicnonmetallicmaterialBythisdefinition,ceramicmaterialswouldalsoincludeglasseshowever,manymaterialsscientistsaddthestipulationthat“ceramic”mustalsobecrystalline陶瓷通常被概括地定义为无机的非金属材料。照此定义,陶瓷材料也应包括玻璃然而许多材料科学家添加了“陶瓷”必须同时是晶体物组成的约定。AglassisaninorganicnonmetallicmaterialthatdoesnothaveacrystallinestructureSuchmaterialsaresaidtobeamorphous玻璃是没有晶体状结构的无机非金属材料。这种材料被称为非结晶质材料。PropertiesofCeramicsandGlassesSomeoftheusefulpropertiesofceramicsandglassesincludehighmeltingtemperature,lowdensity,highstrength,stiffness,hardness,wearresistance,andcorrosionresistance陶瓷和玻璃的特性高熔点、低密度、高强度、高刚度、高硬度、高耐磨性和抗腐蚀性是陶瓷和玻璃的一些有用特性。ManyceramicsaregoodelectricalandthermalinsulatorsSomeceramicshavespecialproperties:someceramicsaremagneticmaterialssomearepiezoelectricmaterialsandafewspecialceramicsaresuperconductorsatverylowtemperaturesCeramicsandglasseshaveonemajordrawback:theyarebrittle许多陶瓷都是电和热的良绝缘体。某些陶瓷还具有一些特殊性能:有些是磁性材料,有些是压电材料,还有些特殊陶瓷在极低温度下是超导体。陶瓷和玻璃都有一个主要的缺点:它们容易破碎。CeramicsarenottypicallyformedfromthemeltThisisbecausemostceramicswillcrackextensivelyieformapowderuponcoolingfromtheliquidstate陶瓷一般不是由熔化形成的。因为大多数陶瓷在从液态冷却时将会完全破碎即形成粉末。Hence,allthesimpleandefficientmanufacturingtechniquesusedforglassproductionsuchascastingandblowing,whichinvolvethemoltenstate,cannotbeusedfortheproductionofcrystallineceramicsInstead,“sintering”or“firing”istheprocesstypicallyused因此,所有用于玻璃生产的简单有效的诸如浇铸和吹制这些涉及熔化的技术都不能用于由晶体物组成的陶瓷的生产。作为替代,一般采用“烧结”或“焙烧”工艺。Insintering,ceramicpowdersareprocessedintocompactedshapesandthenheatedtotemperaturesjustbelowthemeltingpointAtsuchtemperatures,thepowdersreactinternallytoremoveporosityandfullydensearticlescanbeobtained在烧结过程中,陶瓷粉末先挤压成型然后加热到略低于熔点温度。在这样的温度下,粉末内部起反应去除孔隙并得到十分致密的物品。Anopticalfibercontainsthreelayers:acoremadeofhighlypureglasswithahighrefractiveindexforthelighttotravel,amiddlelayerofglasswithalowerrefractiveindexknownasthecladdingwhichprotectsthecoreglassfromscratchesandothersurfaceimperfections,andanoutpolymerjackettoprotectthefiberfromdamage光导纤维有三层:核心由高折射指数高纯光传输玻璃制成,中间层为低折射指数玻璃,是保护核心玻璃表面不被擦伤和完整性不被破坏的所谓覆层,外层是聚合物护套,用于保护光导纤维不受损。Inorderforthecoreglasstohaveahigherrefractiveindexthanthecladding,thecoreglassisdopedwithasmall,controlledamountofanimpurity,ordopant,whichcauseslighttotravelslower,butdoesnotabsorbthelight为了使核心玻璃有比覆层大的折射指数,在其中掺入微小的、可控数量的能减缓光速而不会吸收光线的杂质或搀杂剂。Becausetherefractiveindexofthecoreglassisgreaterthanthatofthecladding,lighttravelinginthecoreglasswillremaininthecoreglassduetototalinternalreflectionaslongasthelightstrikesthecorecladdinginterfaceatananglegreaterthanthecriticalangle由于核心玻璃的折射指数比覆层大,只要在全内反射过程中光线照射核心覆层分界面的角度比临界角大,在核心玻璃中传送的光线将仍保留在核心玻璃中。Thetotalinternalreflectionphenomenon,aswellasthehighpurityofthecoreglass,enableslighttotravellongdistanceswithlittlelossofintensity全内反射现象与核心玻璃的高纯度一样,使光线几乎无强度损耗传递长距离成为可能。Composites复合材料CompositesareformedfromtwoormoretypesofmaterialsExamplesincludepolymerceramicandmetalceramiccompositesCompositesareusedbecauseoverallpropertiesofthecompositesaresuperiortothoseoftheindividualcomponents复合材料由两种或更多材料构成。例子有聚合物陶瓷和金属陶瓷复合材料。之所以使用复合材料是因为其全面性能优于组成部分单独的性能。Forexample:polymerceramiccompositeshaveagreatermodulusthanthepolymercomponent,butaren’tasbrittleasceramicsTwotypesofcompositesare:fiberreinforcedcompositesandparticlereinforcedcomposites例如:聚合物陶瓷复合材料具有比聚合物成分更大的模量,但又不像陶瓷那样易碎。复合材料有两种:纤维加强型复合材料和微粒加强型复合材料。FiberreinforcedCompositesReinforcingfiberscanbemadeofmetals,ceramics,glasses,orpolymersthathavebeenturnedintographiteandknownascarbonfibersFibersincreasethemodulusofthematrixmaterial纤维加强型复合材料加强纤维可以是金属、陶瓷、玻璃或是已变成石墨的被称为碳纤维的聚合物。纤维能加强基材的模量。Thestrongcovalentbondsalongthefiber’slengthgivethemaveryhighmodulusinthisdirectionbecausetobreakorextendthefiberthebondsmustalsobebrokenormoved沿着纤维长度有很强结合力的共价结合在这个方向上给予复合材料很高的模量,因为要损坏或拉伸纤维就必须破坏或移除这种结合。Fibersaredifficulttoprocessintocomposites,makingfiberreinforcedcompositesrelativelyexpensive把纤维放入复合材料较困难,这使得制造纤维加强型复合材料相对昂贵。Fiberreinforcedcompositesareusedinsomeofthemostadvanced,andthereforemostexpensivesportsequipment,suchasatimetrialracingbicycleframewhichconsistsofcarbonfibersinathermosetpolymermatrix纤维加强型复合材料用于某些最先进也是最昂贵的运动设备,例如计时赛竞赛用自行车骨架就是用含碳纤维的热固塑料基材制成的。Bodypartsofracecarsandsomeautomobilesarecompositesmadeofglassfibersorfiberglassinathermosetmatrix竞赛用汽车和某些机动车的车体部件是由含玻璃纤维或玻璃丝的热固塑料基材制成的。Fibershaveaveryhighmodulusalongtheiraxis,buthavealowmodulusperpendiculartotheiraxisFibercompositemanufacturersoftenrotatelayersoffiberstoavoiddirectionalvariationsinthemodulus纤维在沿着其轴向有很高的模量,但垂直于其轴向的模量却较低。纤维复合材料的制造者往往旋转纤维层以防模量产生方向变化。ParticlereinforcedcompositesParticlesusedforreinforcingincludeceramicsandglassessuchassmallmineralparticles,metalparticlessuchasaluminum,andamorphousmaterials,includingpolymersandcarbonblack微粒加强型复合材料用于加强的微粒包含了陶瓷和玻璃之类的矿物微粒,铝之类的金属微粒以及包括聚合物和碳黑的非结晶质微粒。Particlesareusedtoincreasethemodulusofthematrix,todecreasethepermeabilityofthematrix,todecreasetheductilityofthematrixAnexampleofparticlereinforcedcompositesisanautomobiletirewhichhascarbonblackparticlesinamatrixofpolyisobutyleneelastomericpolymer微粒用于增加基材的模量、减少基材的渗透性和延展性。微粒加强型复合材料的一个例子是机动车胎,它就是在聚异丁烯人造橡胶聚合物基材中加入了碳黑微粒。Polymers聚合材料Apolymerhasarepeatingstructure,usuallybasedonacarbonbackboneTherepeatingstructureresultsinlargechainlikemoleculesPolymersareusefulbecausetheyarelightweight,corrosionresistant,easytoprocessatlowtemperaturesandgenerallyinexpensive聚合物具有一般是基于碳链的重复结构。这种重复结构产生链状大分子。由于重量轻、耐腐蚀、容易在较低温度下加工并且通常较便宜,聚合物是很有用的。Someimportantcharacteristicsofpolymersincludetheirsizeormolecularweight,softeningandmeltingpoints,crystallinity,andstructureThemechanicalpropertiesofpolymersgenerallyincludelowstrengthandhightoughnessTheirstrengthisoftenimprovedusingreinforcedcompositestructures聚合材料具有一些重要特性,包括尺寸或分子量、软化及熔化点、结晶度和结构。聚合材料的机械性能一般表现为低强度和高韧性。它们的强度通常可采用加强复合结构来改善。ImportantCharacteristicsofPolymersSizeSinglepolymermoleculestypicallyhavemolecularweightsbetween,and,,gmolthatcanbemorethan,repeatingunitsdependingonthepolymerstructure!聚合材料的重要特性尺寸:单个聚合物分子一般分子量为,到,,gmol之间,具体取决于聚合物的结构这可以比,个重复单元还多。Themechanicalpropertiesofapolymeraresignificantlyaffectedbythemolecularweight,withbetterengineeringpropertiesathighermolecularweights聚合物的分子量极大地影响其机械性能,分子量越大,工程性能也越好。ThermaltransitionsThesofteningpointglasstransitiontemperatureandthemeltingpointofapolymerwilldeterminewhichitwillbesuitableforapplicationsThesetemperaturesusuallydeterminetheupperlimitforwhichapolymercanbeused热转换性:聚合物的软化点玻璃状转化温度和熔化点决定了它是否适合应用。这些温度通常决定聚合物能否使用的上限。Forexample,manyindustriallyimportantpolymershaveglasstransitiontemperaturesneartheboilingpointofwater,,andtheyaremostusefulforroomtemperatureapplicationsSomespeciallyengineeredpolymerscanwithstandtemperaturesashighas例如,许多工业上的重要聚合物其玻璃状转化温度接近水的沸点,,它们被广泛用于室温下。而某些特别制造的聚合物能经受住高达的温度。CrystallinityPolymerscanbecrystallineoramorphous,buttheyusuallyhaveacombinationofcrystallineandamorphousstructuressemicrystalline结晶度:聚合物可以是晶体状的或非结晶质的,但它们通常是晶体状和非结晶质结构的结合物半晶体。InterchaininteractionsThepolymerchainscanbefreetoslidepastoneanotherthermoplasticortheycanbeconnectedtoeachotherwithcrosslinksthermosetorelastomerThermoplasticscanbereformedandrecycled,whilethermosetsandelastomersarenotreworkable原子链间的相互作用:聚合物的原子链可以自由地彼此滑动热可塑性或通过交键互相连接热固性或弹性。热可塑性材料可以重新形成和循环使用,而热固性与弹性材料则是不能再使用的。IntrachainstructureThechemicalstructureofthechainsalsohasatremendouseffectonthepropertiesDependingonthestructurethepolymermaybehydrophilicorhydrophobiclikesorhateswater,stifforflexible,crystallineoramorphous,reactiveorunreactive链内结构:原子链的化学结构对性能也有很大影响。根据各自的结构不同,聚合物可以是亲水的或憎水的喜欢或讨厌水、硬的或软的、晶体状的或非结晶质的、易起反应的或不易起反应的。第二单元TheunderstandingofheattreatmentisembracedbythebroaderstudyofmetallurgyMetallurgyisthephysics,chemistry,andengineeringrelatedtometalsfromoreextractiontothefinalproduct对热处理的理解包含于对冶金学较广泛的研究。冶金学是物理学、化学和涉及金属从矿石提炼到最后产物的工程学。HeattreatmentistheoperationofheatingandcoolingametalinitssolidstatetochangeitsphysicalpropertiesAccordingtotheprocedureused,steelcanbehardenedtoresistcuttingactionandabrasion,oritcanbesoftenedtopermitmachining热处理是将金属在固态加热和冷却以改变其物理性能的操作。按所采用的步骤,钢可以通过硬化来抵抗切削和磨损,也可以通过软化来允许机加工。Withtheproperheattreatmentinternalstressesmayberemoved,grainsizereduced,toughnessincreased,orahardsurfaceproducedonaductileinteriorTheanalysisofthesteelmustbeknownbecausesmallpercentagesofcertainelements,notablycarbon,greatlyaffectthephysicalproperties使用合适的热处理可以去除内应力、细化晶粒、增加韧性或在柔软材料上覆盖坚硬的表面。因为某些元素尤其是碳的微小百分比极大地影响物理性能,所以必须知道对钢的分析。Alloysteelowetheirpropertiestothepresenceofoneormoreelementsotherthancarbon,namelynickel,chromium,manganese,molybdenum,tungsten,silicon,vanadium,andcopperBecauseoftheirimprovedphysicalpropertiestheyareusedcommerciallyinmanywaysnotpossiblewithcarbonsteels合金钢的性质取决于其所含有的除碳以外的一种或多种元素,如镍、铬、锰、钼、钨、硅、钒和铜。由于合金钢改善的物理性能,它们被大量使用在许多碳钢不适用的地方。ThefollowingdiscussionappliesprincipallytotheheattreatmentofordinarycommercialsteelsknownasplaincarbonsteelsWiththisprocesstherateofcoolingisthecontrollingfactor,rapidcoolingfromabovethecriticalrangeresultsinhardstructure,whereasveryslowcoolingproducestheoppositeeffect下列讨论主要针对被称为普通碳钢的工业用钢而言。热处理时冷却速率是控制要素,从高于临界温度快速冷却导致坚硬的组织结构,而缓慢冷却则产生相反效果。ASimplifiedIroncarbonDiagram简化铁碳状态图Ifwefocusonlyonthematerialsnormallyknownassteels,asimplifieddiagramisoftenused如果只把注意力集中于一般所说的钢上,经常要用到简化铁碳状态图。ThoseportionsoftheironcarbondiagramnearthedeltaregionandthoseabovecarboncontentareoflittleimportancetotheengineerandaredeletedAsimplifieddiagram,suchastheoneinFig,focusesontheeutectoidregionandisquiteusefulinunderstandingthepropertiesandprocessingofsteel铁碳状态图中靠近三角区和含碳量高于的那些部分对工程师而言不重要,因此将它们删除。如图所示的简化铁碳状态图将焦点集中在共析区,这对理解钢的性能和处理是十分有用的。Thekeytransitiondescribedinthisdiagramisthedecompositionofsinglephaseausteniteγtothetwophaseferritepluscarbidestructureastemperaturedrops在此图中描述的关键转变是单相奥氏体γ随着温度下降分解成两相铁素体加渗碳体组织结构。Controlofthisreaction,whicharisesduetothedrasticallydifferentcarbonsolubilityofausteniteandferrite,enablesawiderangeofpropertiestobeachievedthroughheattreatment控制这一由于奥氏体和铁素体的碳溶解性完全不同而产生的反应,使得通过热处理能获得很大范围的特性。Tobegintounderstandtheseprocesses,considerasteeloftheeutectoidcomposition,carbon,beingslowcooledalonglinexx’inFigAttheuppertemperatures,onlyausteniteispresent,thecarbonbeingdissolvedinsolidsolutionwiththeironWhenthesteelcoolsto,severalchangesoccursimultaneously为了理解这些过程,考虑含碳量为的共析钢,沿着图的xx’线慢慢冷却。在较高温度时,只存在奥氏体,的碳溶解在铁里形成固溶体。当钢冷却到时,将同时发生若干变化。TheironwantstochangefromtheFCCaustenitestructuretotheBCCferritestructure,buttheferritecanonlycontaincarboninsolidsolution铁需要从面心立方体奥氏体结构转变为体心立方体铁素体结构,但是铁素体只能容纳固溶体状态的的碳。TherejectedcarbonformsthecarbonrichcementiteintermetallicwithcompositionFeCInessence,thenetreactionattheeutectoidisausteniteCferriteCcementiteC被析出的碳与金属化合物FeC形成富碳的渗碳体。本质上,共析体的基本反应是奥氏体的碳铁素体的碳渗碳体的碳。Sincethischemicalseparationofthecarboncomponentoccursentirelyinthesolidstate,theresultingstructureisafinemechanicalmixtureofferriteandcementiteSpecimenspreparedbypolishingandetchinginaweaksolutionofnitricacidandalcoholrevealthelamellarstructureofalternatingplatesthatformsonslowcooling由于这种碳成分的化学分离完全发生在固态中,产生的组织结构是一种细致的铁素体与渗碳体的机械混合物。通过打磨并在弱硝酸酒精溶液中蚀刻制备的样本显示出由缓慢冷却形成的交互层状的薄片结构。Thisstructureiscomposedoftwodistinctphases,buthasitsownsetofcharacteristicpropertiesandgoesbythenamepearlite,becauseofitsresemblancetomotherofpearlatlowmagnification这种结构由两种截然不同的状态组成,但它本身具有一系列特性,且因与低倍数放大时的珠母层有类同之处而被称为珠光体。SteelshavinglessthantheeutectoidamountofcarbonlessthanareknownashypoeutectoidsteelsConsidernowthetransformationofsuchamaterialrepresentedbycoolingalonglineyy’inFig含碳量少于共析体低于的钢称为亚共析钢。现在来看这种材料沿着图中yy’线冷却的转变情况。Athightemperatures,thematerialisentirelyaustenite,butuponcoolingentersaregionwherethestablephasesareferriteandausteniteTielineandlevellawcalculationsshowthatlowcarbonferritenucleatesandgrows,leavingtheremainingaustenitericherincarbon在较高温度时,这种材料全部是奥氏体,但随着冷却就进入到铁素体和奥氏体稳定状态的区域。由截线及杠杆定律分析可知,低碳铁素体成核并长大,剩下含碳量高的奥氏体。At,theausteniteisofeutectoidcompositioncarbonandfurthercoolingtransformstheremainingaustenitetopearliteTheresultingstructureisamixtureofprimaryorproeutectoidferriteferritethatformedabovetheeutectoidreactionandregionsofpearlite在时,奥氏体为共析组成含碳量,再冷却剩余的奥氏体就转化为珠光体。作为结果的组织结构是初步的共析铁素体在共析反应前的铁素体和部分珠光体的混合物。HypereutectoidsteelsaresteelsthatcontaingreaterthantheeutectoidamountofcarbonWhensuchsteelcools,asshowninzz’ofFigtheprocessissimilartothehypoeutectoidcase,exceptthattheprimaryorproeutectoidphaseisnowcementiteinsteadofferrite过共析钢是含碳量大于共析量的钢。当这种钢冷却时,就像图的zz’线所示,除了初步的共析状态用渗碳体取代铁素体外,其余类似亚共析钢的情况。Asthecarbonrichphaseforms,theremainingaustenitedecreasesincarboncontent,reachingtheeutectoidcompositionatAsbefore,anyremainingaustenitetransformstopearliteuponslowcoolingthroughthistemperature随着富碳部分的形成,剩余奥氏体含碳量减少,在时达到共析组织。就像以前说的一样,当缓慢冷却到这温度时所有剩余奥氏体转化为珠光体。Itshouldberememberedthatthetransitionsthathavebeendescribedbythephasediagramsareforequilibriumconditions,whichcanbeapproximatedbyslowcoolingWithslowheating,thesetransitionsoccurinthereversemanner应该记住由状态图描述的这种转化只适合于通过缓慢冷却的近似平衡条件。如果缓慢加热,则以相反的方式发生这种转化。However,whenalloysarecooledrapidly,entirelydifferentresultsmaybeobtained,becausesufficienttimeisnotprovidedforthenormalphasereactionstooccur,insuchcases,thephasediagramisnolongerausefultoolforengineeringanalysis然而,当快速冷却合金时,可能得到完全不同的结果。因为没有足够的时间让正常的状态反应发生,在这种情况下对工程分析而言状态图不再是有用的工具。Hardening淬火Hardeningistheprocessofheatingapieceofsteeltoatemperaturewithinoraboveitscriticalrangeandthencoolingitrapidly淬火就是把钢件加热到或超过它的临界温度范围,然后使其快速冷却的过程。Ifthecarboncontentofthesteelisknown,thepropertemperaturetowhichthesteelshouldbeheatedmaybeobtainedbyreferencetotheironironcarbidephasediagramHowever,ifthecompositionofthesteelisunknown,alittlepreliminaryexperimentationmaybenecessarytodeterminetherange如果钢的含碳量已知,钢件合适的加热温度可参考铁碳合金状态图得到。然而当钢的成分不知道时,则需做一些预备试验来确定其温度范围。Agoodproceduretofollowistoheatquenchanumberofsmallspecimensofthesteelatvarioustemperaturesandobservetheresult,eitherbyhardnesstestingorbymicroscopicexaminationWhenthecorrecttemperatureisobtained,therewillbeamarkedchangeinhardnessandotherproperties要遵循的合适步骤是将这种钢的一些小试件加热到不同的温度后淬火,再通过硬度试验或显微镜检查观测结果。一旦获得正确的温度,硬度和其它性能都将有明显的变化。InanyheattreatingoperationtherateofheatingisimportantHeatflowsfromtheexteriortotheinteriorofsteelatadefiniterateIfthesteelisheatedtoofast,theoutsidebecomeshotterthantheinterioranduniformstructurecannotbeobtained在任何热处理作业中,加热的速率都是重要的。热量以一定的速率从钢的外部传导到内部。如果钢被加热得太快,其外部比内部热就不能得到均匀的组织结构。Ifapieceisirregularinshape,aslowrateisallthemoreessentialtoeliminatewarpingandcrackingTheheavierthesection,thelongermustbetheheatingtimetoachieveuniformresults如果工件形状不规则,为了消除翘曲和开裂最根本的是加热速率要缓慢。截面越厚,加热的时间就要越长才能达到均匀的结果。Evenafterthecorrecttemperaturehasbeenreached,thepieceshouldbeheldatthattemperatureforasufficientperiodoftimetopermititsthickestsectiontoattainauniformtemperature即使加热到正确的温度后,工件也应在此温度下保持足够时间以让其最厚截面达到相同温度。Thehardnessobtainedfromagiventreatmentdependsonthequenchingrate,thecarboncontent,andtheworksizeInalloysteelsthekindandamountofalloyingelementinfluencesonlythehardenabilitytheabilityoftheworkpiecetobehardenedtodepthsofthesteelanddoesnotaffectthehardnessexceptinunhardenedorpartiallyhardenedsteels通过给定的热处理所得到的硬度取决于淬火速率、含碳量和工件尺寸。除了非淬硬钢或部分淬硬钢外,合金钢中合金元素的种类及含量仅影响钢的淬透性工件被硬化到深层的能力而不影响硬度。SteelwithlowcarboncontentwillnotrespondappreciablytohardeningtreatmentAsthecarboncontentinsteelincreasesuptoaround,thepossiblehardnessobtainablealsoincreases含碳量低的钢对淬火处理没有明显的反应。随着钢的含碳量增加到大约,可能得到的硬度也增加。Abovethispointthehardnesscanbeincreasedonlyslightly,becausesteelsabovetheeutectoidpointaremadeupentirelyofpearliteandcementiteintheannealedstatePearliterespondsbesttoheattreatingoperationsandsteelcomposedmostlyofpearlitecanbetransformedintoahardsteel高于此点,由于超过共析点钢完全由珠光体和退火状态的渗碳体组成,硬度增加并不多。珠光体对热处理作业响应最好基

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