WuhanUniversityofTechnology1ENGINEERINGMATERIALSTYPESOFMATERIALS工程材料Materialsmaybegroupedinseveralways.Scientistsoftenclassifymaterialsbytheirstate:solid,liquid,orgas.Theyalsoseparatethemintoorganic(onceliving)andinorganic(neverliving)materials.Forindustrialpurposes,materialsaredividedintoengineeringmaterialsornonengineeringmaterials.Engineeringmaterialsarethoseusedinmanufactureandbecomepartsofproducts.Nonengineeringmaterialsarethechemicals,fuels,lubricants,andothermaterialusedinthemanufacturingprocesswhichdonotbecomepartoftheproduct.材料可以在几个方面进行划分。科学家往往分类材料往往由他们的状态:固体,液体,或气体。他们也将它们分为有机(一旦生活)和无机(从来没有生活)材料。工业用途划分,材料分为工程材料和化学材料。工程材料,是那些用在制造,并被加工成产品。化学材料是化学品,燃料,润滑剂,及其他材料的使用在制造过程中不被加工成产品。Thisgroupingisnotexact.Engineeringmaterialsmaybefurthersubdividedinto:1.Metals.2.Polymers3.Ceramics.Afourthtypeofmaterialsometimelistediscalledacomposite.Materialsinthisgrouparemadeupoftwoormorematerialfromtheengineeringgroups,Eachofthematerialsincompositeretainsitsoriginalcharacteristics.Examplesofcompositesincludewood-,concrete-,glass-reinforcedpolyester,andgraphitepolymeradvancedcomposites.这个分组是不是很准确的。工程材料,可进一步细分为:1、金属2、聚合物3、陶瓷。第四类材料的某个时候上市,是所谓的复合。材料在这个分组的成立两个或两个以上的材料,从工程组,每组的复合材料在保持其原有的特色。例如,复合材料,包括木材,混凝土,玻璃纤维增强聚酯,聚合物和石墨等复合材料。COMMONMETALSPuremetalsareseldomusedincommonindustrialproducts.Purecopperisusedinelectricalapplications,inautomotiveradiators,andgaskets.Purealuminumhasapplicationinthechemicalandelectricalindustries.However,mostmetalsarealloys(combinationsoftwoormoreelements).Thereareover25,000differentiron-carbonalloys(steel)andover200standardcopperalloysincludinganumberofbrasses,bronzes,andnickelsilvers.Eachofthesealloysareidentifiedbyacodenumber.常见的金属纯金属是很少使用共同的工业产品。纯铜是用来在电气应用,在汽车散热器和垫圈。纯铝已应用在化工和电器行业。然而,大多数金属是合金(组合两个或两个以上的元素)。有超过25000不同的铁碳合金(钢铁)和超过200标准铜合金,包括一些黄铜,青铜,镍银。每个这些合金所确定的一编号。Steelisanalloyofironandcarbonwithotherelementsaddedtoproducespecificproperties.钢是合金铁和碳与其他元素添加到产生特定属性。各类型的WuhanUniversityofTechnology2Thevarioustypeofsteelcanbegroupedundertwomajorheading:(1)Carbonsteel.Asteelinwhichthemainalloyingelementiscarbon.Carbonsteelarefurtherdividedintothreegroups.a.Lowcarbonsteel.Thissteelhasacarboncontentoflessthan0.30percent.Itisthemostcommontypeandisoftencalledmildsteel.Itisrelativelyinexpensive,ductile,soft,andiseasilymachinedandforged.Mildsteelcannotbeheat-treated(hardened).Lowcarbonsteelisageneralpurposesteel.b.Mediumcarbonsteel.Thissteelhasacarboncontentbetween0.30percentand0.80.Harderandstrongerthanmildsteel,itcanbehardenedbyheattreating.Mediumcarbonsteelismostcommonlyusedforforgings,castings,andmachinedpartsforautomobiles,agriculturalequipment,machines,andaircraft.c.Highcarbonsteel.Thistypeofsteeliseasilyheat-treatedtoproduceastrong,toughpart.Thematerialhasacarboncontentabove0.80percent.Itfindswideuseinhandtools,cuttingtools,springs,andpianowire.(2)Highalloysteel.Thesesteelscontainsignificantamountsofotherelementsinadditiontocarbon.Thecommonhighalloysteelare:a.Stainlesssteelwhichisproducedbyusingchromiumasasignificantalloyingelementalongwithnickelandothermetals.Theresultisatough,hard,corrosion-resistantmetal.b.Toolsteelwhichisaspecialgroupofhighcarbonsteelsproducedinsmallquantitiestohighqualityspecifications.Toolsteelareusedforawiderangeofcuttingtoolsandformingdies.c.Manganesesteelwhichisanalloycontaining21percentmanganeseandonepercentcarbon.Thismetalisusedinmining,railroad,andconstructionequipmentbecauseofitshightensilestrength.钢可以分为两大类:(1)碳素钢。在其中的主要合金元素是碳。碳钢是进一步分为三类。a.低碳钢。钢中的碳含量小于0.30%。这是最常见的类型和常被人称作是低碳钢。这是相对便宜,韧性,软,很容易加工和伪造的。低碳钢不能热处理(硬化)。低碳钢是一个一般用途的钢。b.中碳结构钢。钢中碳的含量之间的0.30%和0.80。强度大,比低碳钢,可以硬化热处理。中碳结构钢是最常用的锻件,铸件,机械零件,汽车,农业设备,机器和飞机等等用钢。c.高碳钢。这种类型的钢是很容易热处理而拥有很好的强度。该材料中的碳含量高于0.80%。它发现广泛使用加工工具,如切割工具,弹簧,和钢琴丝。(2)高合金钢。这些钢含有大量的其他要素在除碳。高合金钢有:a.不锈钢是所产生的使用铬作为一项重大合金元素,随着镍和其他金属。结果是强硬,硬,耐腐蚀的金属。b.工具钢这是一个特殊的群体高碳钢生产的少量,以高品质规格。工具钢是用于范围广泛的刀具和成形模具。c.锰钢这是一种合金含有21%,锰和碳1%。这种金属是用来在采矿,铁路,和建筑设备,因为它抗拉强度高。PROPERTIESOFMATERIALSAllmaterialhavetheirownpropertiesorcharacteristics.Thesepropertiesmaybearrangedintomajorgroupswhichinclude:Physicalproperties.Mechanicalproperties.Chemicalproperties.材料性能所有的物质都有自己的属性或特征。这些属性或特征体现在各个方面,其中包括:物理性能;力学性能;化学性质;热性能;WuhanUniversityofTechnology3Thermalproperties.ElectricalandMagneticproperties.Opticalproperties.Acousticalproperties.电器及磁学性质;光学性质;声学特性。1.PhysicalPropertiesPhysicalproperties,forthisdiscussion,arerestrictedtothosewhichdescribethebasicfeaturesofthematerial.Thesefeaturesaremeasuredorobservedwithouttheuseofextensivescientificexperiments.Thecommonphysicalpropertiesaresize,shape,density,andporosity.Sizeistheoveralldimensionsoftheobject.Thesedimensions,formostmaterials,aregivenasthickness,width,andlengthorasdiameterandlength.Shapeisthecontouroroutlineoftheobject.,Contourisgiventoanobjectbycurved,notched,sloped,orotherirregularsurfaces.Densityorspecificgravitymeasuresthemassofanobject.Themeasurementisbyweightforaunitoracertainvolume.Typically,densityismeasuredbypoundspercubicfootorkilogramspercubicmeterofmaterial.Densityallowsthemassofonematerialtobecomparedwiththatofothermaterials.Porosityisamea