材料科学与工程专业英语

材料科学与工程专业英语,江苏大学材料学院主讲：杨课程简介,共20学时（课堂14学时，课后6学时）考试：开卷，当堂完成教材：材料科学与工程专业英语第二版匡少平、王世颖主编，化学工业出版社.,主要内容和课时安排,Introductiontomaterialsscienceandengineering(4学时)Metallicmaterialsandalloys（4学时）Ceramics（2学时）Polymer（2学时）Composites（2学时）Nanostructuredmaterials（2学时）,Part1Introductiontomaterialsscienceandengineering,Unit1PhysicalandchemicalpropertiesofmaterialsUnit2Mechanicalpropertiesofmaterials,Unit1Physicalandchemicalpropertiesofmaterials,Physicalpropertiesarethosethatcanbeobservedwithoutchangingtheidentityofthesubstance.Thegeneralpropertiesofmattersuchascolor,density,hardness,areexamplesofphysicalproperties.Propertiesthatdescribehowasubstancechangesintoacompletelydifferentsubstancearecalledchemicalproperties.Flammabilityandcorrosion/oxidationresistanceareexamplesofchemicalproperties.,Ingeneral,someofthemoreimportantphysicalandchemicalpropertiesfromanengineeringmaterialstandpointincludephasetransformationtemperatures,density,specificgravity,thermalconductivity,linearcoefficientofthermalexpansion,electricalconductivityandresistivity,magneticpermeability,andcorrosionresistance,andsoon.,磁导率,PhaseTransformationTemperatures,Whentemperaturerisesandpressureisheldconstant,atypicalsubstancechangesfromsolidtoliquidandthentovapor.Transitionsfromsolidtoliquid,fromliquidtovapor,fromvaportosolidandvisaversaarecalledphasetransformationsortransitions.Sincesomesubstanceshaveseveralcrystalforms,technicallytherecanbesolidtoanothersolidfromphasetransformation.,Meltingpoint:thephasetransitiontemperaturewhereasolidchangestoaliquidBoilingpoint:thetemperatureatwhichthevaporpressureofaliquidequals1atm(101.3kPa),Somematerials,suchasmanypolymers,donotgosimplyfromasolidtoaliquidwithincreasingtemperature.Instead,atsometemperaturebelowthemeltingpoint,theystarttolosetheircrystallinestructurebutthemoleculesremainlinkedinchains,whichresultsinasoftandpliablematerial.Thetemperatureatwhichasolid,glassymaterialbeginstosoftenandflowiscalledtheglasstransitiontemperature.,Density,Masscanbethinlydsitrbutedasinapillow,ortightlypackedasinablockoflead.质量可以像枕头似地稀疏地分布，也可以像铅那样紧紧地堆积在一起。Thespacethemassoccupiesisitsvolume,andthemassperunitofvolumeisitsdensity.,Mass(m)isafundamentalmeasureoftheamountofmatter.Weight(w)isameasureoftheforceexertedbyamassandthisforceisproducedbytheaccelerationofgravity.Therefore,onthesurfaceofearth,themassofanobjectisdeterminedbydividingtheweightofanobjectby9.8m/s2(theaccelerationofgravityonthesurfaceoftheearth).,因此，在地球表面，物体的质量由物体的重量和重力加速度所决定。Sincewearetypicallycomparingthingsonthesurfaceoftheearth,theweightofanobjectiscommonlyusedratherthancalculatingitsmass.,Thedensity(r)ofamaterialdependsonthephaseitisinandthetemperature(thedensityofliquidsandgasesisverytemperaturedependent).Waterintheliquidstatehasadensityof1g/cm3at4.Icehasadensityof0.9171g/cm3at0,anditshouldbenotedthatthisdecreaseindensityforthesolidphaseisunusual.Foralmostallothersubstances,thedensityofthesolidphaseisgreaterthanthatoftheliquidphase.Watervaporhasadensityof0.051g/cm3.,SpecificGravity,Specificgravityistheratioofdensityofasubstancecomparedtothedensityoffreshwaterat4.Atthistemperaturethedensityofwaterisatitsgreatestvalueandequalto1g/mL.Sincespecificgravityisaratio,soithasnounits.Anobjectwillfloatinwaterifitsdensityislessthanthedensityofwaterandsinkifitsdensityisgreaterthanthatofwater.,Similarly,anobjectwithspecificgravitylessthan1willfloatandthosewithaspecificgravitygreaterthan1willsink.SpecificgravityvaluesforafewcommonsubstancesareAu,19.3;mercury,13.6;alcohol,0.7893;benzene,0.8786.Notethatsincewaterhasdensityof1g/cm3,thespecificgravityisthesameasthedensityofthematerialmeasureding/cm3.,MagneticPermeability,Magneticpermeabilityorsimplypermeabilityistheeasewithwhichamaterialcanbemagnetized.Itisaconstantofproportionalitythatexistsbetweenmagneticinductionandmagneticfieldintensity.,磁感应强度,磁场强度,Thisconstantisequaltoapproximately1.25710-6Henrypermeter(H/m)infreespace(avacuum).Inothermaterialsitcanbemuchdifferent,oftensubstantiallygreaterthanthefree-spacevalue,whichissymbolized0.其他材料却截然不同，通常远大于真空值。,Materialsthatcausethelinesoffluxtomovefartherapart,resultinginadecreaseinmagneticfluxdensitycomparedwithavacuum,arecalleddiamagnetic.Materialsthatconcentratemagneticfluxbyafactorofmorethanonebutlessthanorequaltotenarecalledparamagnetic;materialsthatconcentratethefluxbyafactorofmorethantenarecalledferromagnetic.Thepermeabilityfactorsofsomesubstanceschangewithrisingorfallingtemperature,orwiththeintensityoftheappliedmagneticfield.,Exercises,TranslatethefollowingintoChinesePhasetransformationtemperaturesSpecificgravityThermalconductivityThemeltingpointTheaccelerationofgravityMagneticpermeabilityMagneticlinesoffluxferromagnetic,TranslatethefollowingintoEnglish相对密度沸点磁感应热导率玻璃转变温度有色金属线性热膨胀系数单位体积质量,Unit2MechanicalPropertiesofMaterials,Themechanicalpropertiesofamaterialarethoseonesthatinvolveareactiontoanappliedload.Thecommonpropertiesconsideredarestrength,ductility,hardness,impactresistance,andfracturetoughness.,强度、延展性、硬度、冲击强度、断裂韧性,Moststructuralmaterialsareanisotropic,whichmeansthattheirmaterialpropertiesvarywithorientation.Thevariationinpropertiescanbeduetodirectionalityinthemicrostructure(texture)fromformingorcoldworkingoperation,thecontrolledalignmentoffiberreinforcementandavarietyofothercauses.Mechanicalpropertiesaregenerallyspecifictoproductformsuchassheet,plate,extrusion,casting,forging,andetc.,Additionally,itiscommontoseemechanicalpropertylistedbythedirectionalgrainstructureofthematerial.Inproductssuchassheetandplate,therollingdirectioniscalledthelongitudinaldirection,thewidthoftheproductiscalledthetransversedirection,andthethicknessiscalledtheshorttransversedirection.longitudinallnditju:dinl轴向Transversetrnsv:s横向,Themechanicalpropertiesofamaterialarenotconstantandoftenchangeasafunctionoftemperature,rateofloading,andotherconditions.Forexample,temperaturesbelowroomtemperaturegenerallycauseanincreaseinstrengthpropertiesofmetallicalloys;whileductility,fracturetoughness,andelongationusuallydecrease.Temperaturesaboveroomtemperatureusuallycauseadecreaseinthestrengthpropertiesofmetallicalloys.Ductilitymayincreaseordecreasewithincreasingtemperaturedependingonthesamevariables,Itshouldbealsobenotedthatthereisoftensignificantvariabilityinthevaluesobtainedwhenmeasuringmechanicalproperties.Seeminglyidenticaltestspecimenfromthesamelotofmaterialswilloftenproducecondsideralbedifferentresults.Therefore,multipletestsarecommonlyconductedtodeterminemechanicalpropertiesandvaluesreportedcanbeanaveragevalueorcalculatedstatisticalminimumvalue.Also,arangeofvaluesissometimesreportedinordertoshowvariability.,loading,Theapplicationofaforcetoanobjectisknownasloading.Materialscanbesubjectedtomanydifferentloadingscenariosandamaterialsperformanceisdepentontheloadingconditions.Therearefivefundamentalloadingconditions:tension,compression,bending,shear,andtorsion.scenarios:情况情节,Tensionisthetypeofloadinginwhichthetwosectionsofmaterialoneithersideofaplanetendtobepulledapartorelongated.Compressionisthereverseoftensileloadingandinvolvespressingthematerialtogether.Loadingbybendinginvolvesapplyingaloadinamannerthatcausesamaterialtocurveandresultsincompressingthematerialononesideandstretchingitontheother.,Shearinvolvesapplyingaloadparalleltoaplanewhichcausedthematerialononesideoftheplanetowanttoslideacrossthematerialontheothersideoftheplane.Torsionistheapplicationofaforcethatcausestwistinginamaterial.,Ifamaterialissubjectedtoaconstantforce,itiscalledstaticloading.Iftheloadingofthematerialisnotconstantbutinsteadfluctuates,itiscalleddynamicorcyclicloading.Thewayamaterialisloadedgreatlyaffectsitsmechanicalpropertiesandlargelydetermineshow,orif,acomponentwillfail;andwhetheritwillshowwarningsignsbeforefailureactuallyoccurs.,Stress,Thetermstress(S)isusedtoexpresstheloadingintermsofforceappliedtoacertaincross-sectionalareaofanobject.Fromtheperspectiveofloading,stressistheappliedforceorsystemofforcesthattendstodeformabody.Fromtheperstectiveofwhatishappeningwithinamaterial,stressistheinternaldistributionofforceswithinabodythatbalanceandreacttotheloadsappliedtoit.Thestressdistributionmayormaynotbeuniform,dependingonthenatureoftheloadingcondition.,Forexample,abarloadedinpuretensionwillessentiallyhaveauniformtensilestressdistribution.However,abarloadedinbendingwillhaveastressdistributionthatchangeswithDistanceperpendiculartothenormalaxis.,垂直的,Strain,Strainistheresponseofasystemtoanappliedstress.Whenamaterialisloadedwithaforce,itproducesastress,whichthencausesamaterialtodeform.Engineeringstrainisdefinedastheamountofdeformationinthedirectionoftheappliedforcedividedbytheinitiallengthofthematerial.Theresultsinaunitlessnumber,althoughitisoftenleftintheunsimplifiedform,suchasinchesperinchormeterspermeter.,工程应变可定义为：所施加力方向上的材料的改变量与材料原始长度的比值,Forexample,thestraininabarthatisbeingstretchedintensionistheamountofelongationorchangeinlengthdividedbyitsoriginallength.Asinthecaseofstress,thestraindistributionmayormaynotbeuniforminacomplexstructuralelement,dependingonthenatureoftheloadingcondition.,Ifthestressissmall,thematerialmayonlystrainasmallamountandthematerialwillreturntoitsoriginalsizeafterthestressisreleased.Thisiscalledelasticdeformation,becauseoflikingelastic,itreturnstoitsunstressedstate.Elasticdeformationonlyoccursinamaterialwhenstressesarelowerthanacriticalstresscalledtheyieldstrength.Ifamaterialisloadedbeyonditelasticlimit,thematerialwillremaininadeformedconditionaftertheloadisremoved.Thisiscalledplasticdeformation.,Tensileproperties,Tensilepropertiesindicatehowthematerialwillreacttoforcesbeingappliedintension.Atensiletestisafundamentalmechanicaltestwhereacarefullypreparedspecimenisloadedinaverycontrolledmannerwhilemeasuringtheappliedloadandtheelongationofthespecimenoversomedistance.Tensiletestsareusedtodeterminethemodulusofelasticity,elasticlimit,elongation,proportionallimit,reductioninarea,tensilestrength,yieldpoint,yieldstrengthandothertensileproperties.,拉伸试验是一种基本的力学测试，它是对所制备好的样品施加一种可以控制的负荷，来测量所施加的负荷和在一段距离内样品的拉长。,Hardness,Hardnessistheresistanceofamaterialtolocalizeddeformation.Thetermcanapplytodeformationfromindentation,scratching,cuttingorbending.Inmetals,ceramicsandmostpolymers,thedeformationconsideredisplasticdeformationofthesurface.Forelastomersandsomepolymers,hardnessisdefinedattheresistancetodeformationofthesurface.,Thelackofafundamentaldefinitionindicatesthathardnessisnotbeabasicpropertyofamaterial,butratheracompositeonewithcontributionsfromtheyieldstrength,workhardening,truetensilestrength,modulus,andotherfactors.Hardnessmeasurementsarewidelyusedforthequalitycontrolofmaterialsbecausetheyarequickandconsideredtobenondestructivetestswhenthemarksorindentationsproducedbythetestareinlowstressareas.,Toughness,Theablityofametaltodeformplasticallyandtoabsorbenergyintheprocessbeforefractureistermedtoughness.Theemphasisofthisdefinitionshouldbeplacedontheablitytoabsorbenergybeforefracture.Recallthatductilityisameasureofhowmuchsomethingdeformsplasticallybeforefracture,butjustbecauseamaterialisductiledoesnotmakeittough.,Thekeytotoughnessisagoodcombinationofstrengthandductility.Amaterialwithhighstrengthandhighductilitywillhavemoretoughnessthanamaterialwithlowstrengthandhighductility.Therefore,onewaytomeasuretoughnessisbycalculatingtheareaunderthestressstraincurvefromatensiletest.Thisvalueissimplycalled“materialtoughness”andithasunitsofenergypervolume.Materialtoughnessequatestoaslowabsorptionofenergybythematerial.,Exercises,TranslatethefollowingintoChinesetheservicelifethelongitudinaldirectionthetransversedirectiondynamicorcyclicloadingtheinitiallengthofthematerialelasticdeformationplasticdeformationlocalizeddoformation,TranslatethefollowingintoEnglish实验样品静负荷作用力垂直轴工程应变临界应力屈服强度应力面积应力-应变曲线,PartMetallicMaterialsandAlloys,Unit3MetalsandTheirApplications,IntroductiontoMetalsandAlloys,Inchemistry,ametalisdefinedasanelementthatreadilyloseselectronstoformpositiveions(cations)andformsmetallicbondsbetweenothermetalatmos(formingionicbondswithnon-metals).,Themetalsoftheperiodictableareformallydefinedaslithium,beryllium,sodium,magnesium,aluminium,potassium,calcium,scandium,titanium,vanadium,chromium,zirconium,niobium,molybdenum,technetium,ruthenium,rhodium,palladium,silver,cadmium,indium,tin,antimony,caesium,barium,lanthanum,hafnium,tantalum,tungsten,rhenium,osmium,iridium,platinum,gold,mercury,thallium,leadandbismuth.,berilim铍,liim锂,sudim钠,mgni:zim镁,.ljuminim铝,ptsim钾,klsim钙,skndim钪,taiteinim钛,vneidim钒,krumim铬,z:kunim锆,naiubim铌,mlibdinm钼,tekni:im锝Tc,ru:i:nim钌,rudim铑,pleidim钯,silv银,kdmim镉,indim铟,tin锡,ntimni锑,si:zim铯,brim钡,lnnm镧,hfnim铪,tntlm钽,tstn钨,ri:nim铼,zmim锇,airidim铱,pltinm铂,m:kjuri汞,lim铊,li:d铅,bizm铋,Metalsaresometimesdescribedasalatticeofpositiveionssurroundedbyacloudofdelocalizedelectrons.Metalsareoneofthethreegroupsofelementsasdistinguishedbytheirionizationandbondingproperties,alongwiththemetalloidsandnonmetals.ionization：.ainaizein,.ainzein离子化，电离metalloid:metlid,metl.id类金属,Analternativedefinitionofmetalsisthattheyhaveoverlappingconductionbandsandvalencebandsintheirelectronicstructure.Thisdefinitionopensupthecategoryformetallicpolymersandotherorganicmetals,whichhavebeenmadebyresearchersandemployedinhigh-techdevices.Thesesyntheticmaterialsoftenhavethecharacteristicsilvery-greyreflectiveness(luster)ofelementalmetals.,Categories,BasemetalInchemistry,theterm“basemetal”isusedinformallytoametalthatoxidizesorcorrodesrelativelyeasily,andreactsvariablywithdilutehydrochloricacid(HCl)toformhydrogen.Examplesincludeiron,nickel,leadandzinc.Copperisconsideredabasemetalasitoxidizesrelativelyeasily,althoughitdoesnotreactwithHCl.Itiscommonlyusedinoppositiontonoblemetal.,Inalchemy,abasemetalwasacommonandinexpensivemetal,asopposedtopreciousmetals,mainlygoldandsilver.Alongtimegoalofthealchemistswasthetransmutationofbasemetalsintopreciousmetals.Innumismatics,coinsusedtoderivetheirvalueprimarilyfromthepreciousmetalcontent.Mostmoderncurrenciesarefiatcurrency,allowingthecoinstobemadeofbasemetal.,Ferrousmetal:Theterm“ferrous”isderivedfromthelatinwordmeaning“containingiron”.Thiscanincludepureiron,suchaswroughtiron,oranalloysuchassteel.Ferrousmetalsareoftenmagnetic,butnotexclusively.wroughtr:tiron:熟铁,Noblemetal:Noblemetalsareonesthatareresistanttocorrosionoroxidation,unlikemostbasemetals.Theytendtobepreciousmetal,oftenduetoperceivedrarity.Examplesincludetantalum,gold,platinumandrhodium.Ta,Au,Pt,Rh,Preciousmetal:Apreciusmetalisararemetallicchemicalelementofhigheconomicvalue.Chemically,thepreciousmetalsarelessreactivethanmostelements,havehighlusterandhighelectricalconductivity.Historically,preciousmetalswereimprotantascurrency,butarenowregardedmainlyasinvestmentandindustricalcommodities.,Thedemandforpreciousmetalsisdrivennotonlybytheirpraticaluse,butalsobytheirroleasinvestmentsandastoreofvalue.Palladiumwas,asofsummer2006,valuedatalittleunderhalfthepriceofgold,andplatinumataroundtwicethatofgold.Silverissubstantiallylessexpensivethanthsesmetals,butisoftentraditionallyconsideredapreciousmetalforitsroleincoinageandjewelry.,Extraction,MetalsareoftenextractedfromtheEarthbymeansofmining,resultinginoresthatarerelativelyrichsourcesoftherequisiteelements.Oreislocatedbyprospectingtechniques,followedbytheexplorationandexaminationofdeposits.Mineralsourcesaregenerallydividedintosurfacemines,whichareminedbyexcavationusingheavyequipment,andsubsurfacemines.,通过勘探技术确定矿石的位置，然后再对矿床进行开发和探测,Oncetheoreismined,themetalsmustbeextracted,usuallybychemicalorelectrolyticreduction.Pyrometallurgyuseshightemperaturestoconvertoreintorawmetals,whilehydrometallurgyemploysaqueouschemistryforthesamepurpose.Themethodsuseddependonthemetalandtheircontaminants.pyrometallurgy:.pairmetl:di火法冶金hydrometallurgy：.haidrumetl:di水法冶金,Applications,Somemetalsandmetalalloyspossesshighstructuralstrengthperunitmass,makingthemusefulmaterialsforcarryinglargeloadsorresistingimpactdamage.Metalalloyscanbeengineeredtohavehighresistancetoshear,torqueanddeformation.Howeverthesamemetalcanalsobevulnerabletofatiguedamagethroughrepeateduse,orfromsuddenstressfailurewhenaloadcapacityisexceeded.,一些金属和金属合金具有很高的单位质量结构强度，使得它们成为承载大负荷或抗撞击损伤的有效材料。,Thestrengthandresilienceofmetalshasledtotheirfrequentuseinhigh-risebuildingandbridgeconstruction,aswellasmostvehichles,manyappliances,tools,pipes,non-illuminatedsignsandrailroadtracks.Thetwomostcommonlyusedstructuralmetals,ironandaluminium,arealsothemostabundantmetalsintheEarthscrust.,铝和铁是两种最常用的结构材料，也是地壳中含量最丰富的金属。,Metalsaregoodconductors,makingthemvaluableinelectricalapplicancesandforcarryinganelectriccurrentoveradistancewithlittleenergylost.Electricalpowergridsrelyonmetalcablestodistributeelectricity.Homeelectricalsystems,forthemostpart,arewiredwithcopperwireforitsgoodconductingproperties.,Thethermalconductivityofmetalisusefulforcontainerstoheatmaterialsoveraflame.Metalisalsousedforheatsinkstoprotectsensitiveequipmentfromoverheating.Thehighreflectivityofsomemetalsisimportantintheconstructionofmirrors,includingprecisionastronomicalinstruments.Thislastpropertycanalsomakemetallicjewelryaestheticallyappealing.,散热器,.strnmikl天文学的,i:setikli有审美能力的,Somemetalshavespecializeduses.RadioactivemetalssuchasUraniumandPlutoniumareusedinnuclearpowerplantstoproduceenergyvianuclearfission.Mercuryisaliquidatroomtemperatureandisusedinswitchestocompleteacircuitwhenitflowsovertheswitchcontacts.Shapememoryalloyisusedforapplicationssuchaspipes,fastenersandvascularstents.Howevertheyareverygoodatconductingelectricityandheat.,jureinim铀,plu:tunim钚,Astronomystrnmi,Inthespecializedusageofastronomyandastrophysics,theterm“metal”isoftenusedtorefertoanyelementotherthanhydrogenorhelium,includingsubstancesaschemicallynon-metallicasneon,flurine,andoxygen.,在天文学和天体物理学的专业化应用中，金属是指除氢、氦以为的，像氖、氟和氧这些在化学上为非金属的其他元素。,ni:.n氖,NearlyallthehydrogenandheliumintheUniversewascreatedinBigBangnucleosynthesis,whereasallthe“metals”wereproducedbynucleosynthesisinstarsorsupernovae.TheSunandtheMilkyWayGalaxyarecomposedofroughly70%hydrogen,30%helium,and