【精品】材料概论

精品精品 材料概论材料概论 Introduction toMaterials 材料概论 Questions andProblems 习题 材料工程学院1Introduction toMaterials1 1With regardto electronconfiguration what doall theelements inGroup VIIAof thePeriodic Tablehave inmon 1 2Cite the differences betweensubstance andmaterial 1 3Why dowe studymaterials scienceand engineering 1 4Offer anexplanation asto whycovalently bondedmaterials aregenerally lessdense thanionically ormetallically bondedones 1 5What types of bondingwould beexpected for each of the followingmaterials brass rubber barium sulfide BaS solid xenon nylon and aluminumphosphide AlP 1 6What is the difference between theatomic structureand crystalstructure 1 7The unitcell fortin hastetragonal symmetry with aand blattice parametersof0 583and0 318m respectively If itsdensity atomic weight and atomicradius are7 30g cm3 118 69g mol and0 151nm respectively pute theatomic packingfactor 1 8Cite the primary differences between elastic anelastic and plasticdeformation behaviour 1 9Cite fivefactors thatlead toscatter inmeasured materialproperties 1 10Besides themechanical properties and thephysico chemical characteristics of materials which otherfactors should be consideredfor themanufacture of an object 1 11What materialcould beused toinsulate afurnace heatedto1000 Why 1 12To whichclass ofbuilding materialdoes woodbelong 1 13List the materials used in abicycle 1 14Material specificationfor modernathletic shoesis quiteplex In youropinion whatshouldbethe requirement and why 1 15You wishto selectthematerialsneeded tocarry acurrent between the ponentsinside anelectrical black box What materialswould youselect 1 16Describe someof the key mechanicaland physicalproperties wewould considerin selectinga material for anairplane wing 1 17In termsof bonding explain whysilicate materialshave relativelylow densities 1 18A three point bendingtest isperformed ona glassspecimen havinga rectangularcross sectionof heightd5mm andwidth b10mm the distancebetween supportpoints is45mm a Compute theflexural strengthif theload atfracture is290N b The pointof maximumdeflection y oursat centerof thespecimen andis describedby EIFLy483 where Eisthemodulus of elasticity andI isthe cross section momentof inertia Compute y ata loadof266N 2Metallic Materials2 1What are the majordifferencesbetweeniron andsteel 2 2List fiveapplications thatyou encounterevery daythat useferrous metalsand reason s Why thesemetals werechosen for each application Can you think ofa bettermaterialfor the application 2 3List oneapplication thekeystructural difference and the best qualityforeachof the following castirons a ductile castiron b gray castiron c white iron d malleable iron e wrought iron 2 4What isthe majorfunction of the followingin alloysteel a copper b vanadium c chromium d aluminum e lead f nickel and g tungsten 2 5Describe themajor advantages of eachof the following stainlesssteels a martensitic b austenitic and c ferritic 2 6Name threenoble metalsand givean applicationof each 2 7Explain whyaluminum magnesium and titaniumare expensivewhen theyare soreadily availableas raw materials Give areason forrecycling aluminum 2 8Explain thecorrosion resistance mechanismof copperand aluminum Which metaloffers thewidest range of processability 2 9What are a brass b bronze and c refractory metals 2 10 a What moncharacteristic dowhite metalspossess b Provide atypical application foreachof thesemetals c Why islead eliminatedfrom paint plumbing gasoline ceramics cookware and similaruses 2 11List fourproperties ofmagnesium alloys Cite oneexample ofan applicationwhere amagnesium alloywas selectedbecause itpossessed oneof these properties containedin yourlist 2 12Of thenonferrous metalsdiscussed copper aluminum magnesium nickel chromium t itanium gold silver platinum lead tin and zinc a What hasthe higheststrength b Which isthe lightestin weight c Which isthe bestelectrical conductor d Which isthe bestthermal conductor e Which offersthebestcorrosion resistance 2 13What happensto the properties ofhardness strength and modulusofelasticitywith adecrease intemperature 2 14Explain what is meantby ductility 2 15In whatways canfatigue strengthbe improved 2 16In whatstate doesa metalconduct best alloyed orunalloyed 2 17What isthe correlationbetween metalsfor electricaland thermalconductivity 2 18How doesthe metallicbond work and whateffect doesit haveon metals 3Ceramic Materials3 1Based onyour knowledgeof materials define ceramics in itssimplest form Once you ve dohat begin constructinga conceptmap thatincludes yourdefinition of ceramics andthe categoriesof traditionalceramics and advanced ceramics 3 2Take oneof theproperties andsee ifyou cantrace thisproperty backto thecovalent bonding and or crystalstructure For example consider thefact thatglass istransparent but ametal likealuminum isreflective Try toexplain thesedifferences based on the difference inbondingand or crystalstructure 3 3Sketch the following unitcells simple cubic body centeredcubic face centeredcubic andhexagonal close packed Now look upthefollowingcrystal structuresand determinewhich of the structuresyou justsketched aresimilar to thefollowing the rocksalt structure the cesiumchloride structure the fluoritestructure the perovskitestructure 3 4How doesbiomimetics representthe kindof appealoffered byceramics formaterials selection What otherattributes makeceramics petitivewith metalsand polymers 3 5A material s resistanceto theremoval ofits surfacematerial isknown bywhat terms 3 6Explain whythe machiningof fine grained ceramicparts reducestheir strength and toughnessmore thanthat oflarge grained ceramicparts 3 7Surface modificationtechniques aredeveloped andemployed toaomplish whatparticular goals 3 8What isthe maindifferencebetweenCVD andCVI processes 3 9Explain howa materialis affectedby machiningwith eitherdull orimproper tools 3 10Why doductile materialswithstand impactbetter thanbrittle materials 3 11In termsof microstructure why docrystalline ceramicshave different properties frommetals thatare alsocrystalline 3 12Match theceramic tothe applicationfor whichit isbest suited a Tempered glass 1 Grinding andpolishing b Fused silica 2 Furnace windows c Ferrite 3 Protect metalfrom oxidation d Glaze porcelain 4 Computer memorydiscs e 96 silica glass 5 Storm doorglazing f Diamond 6 Contain hotacids3 13Consider thecharacteristicsof the generalclasses of ceramics plastics and metals List theclass thatis generallysuperior inthefollowingcharacteristics then writedown aspecific materialand valueto illustrateits superiority a stiffness b chemical resistance c abundance ofraw materials d tensile strength e lowest coefficientof thermalexpansion f thermal insulation g hardness h impact strength i flexural strength j density 3 14In studyingthe relationshipofafinished productin servicewith itspropertiesandthe processesused toproduce theproduct fromits basicmaterial s one interestingobservation isthat thefinal propertiesdesired ina productare usuallythe causeoftheproblems thatneed tobe overe in itsprocessing An exampletaken fromceramics dealswith thedesired properties of highhardness andtemperature resistance These arethe veryproperties thatmust beovereinprocessing theproduct Using metalsand or polymers cite ageneral statementthat supportsthe foregoingobservation 3 15When selectinga ceramicmaterial toserve asa heatinsulator would amaterial witha highdensity qualify Discuss youranswer 3 16Ceramic armor initially developedfortheVietnam Warand alsoused inthe GulfWar was aposite madeup ofboron carbide B4C and fiberglassplus aramidfiber matting The ceramichas adensity of2 4g cm3 Is thisa low or ahigh density ceramic Explain whyyouthinkthis ceramicwas chosenfor thisapplication 3 17Match thecorrect ceramicto itsfavorable characteristics Some willhave thesame characteristics a Boron nitride 1 Low cost b Graphite 2 Machinable c Al2O3 3 Best lubricity d Glass ceramic 4 Maximum hardness3 18In termsof theiratomic bonding explain whymetals aregood conductorsand mostceramics aregood insulators 3 19Name somegoals ofindustry andsociety thatcaused apush forgreater useofceramics Describe attributesofceramicsthat makethem petitivewith plasticsand metals Contrast traditionalandadvancedceramics 3 20Use diagramsand explanationsto showstress concentrationsplus methodsto toughenceramics including positematrix ceramics Define work of fractureand pareworkoffracture versustensile strengthin glass cements and biomaterials Make sketchesto showmethods ofimproved ceramicstructure forgreater toughness 4The GlassSciences4 1What isglass briefly What roledoes glassplay inour ordinarylife 4 2How toproduce glassin nature Please givesome examples 4 3In moderntimes whatisthe mainusage forglass 4 4What areglass fibers Why canthey beusedintelemunication 4 5How tobe colouredduring the preparation of glass 4 6What kindof glassescan beused aslasers 4 7How toproduce opticalfibers inindustrial technology 4 8What isoxide ornon oxide glass Please givesome examplesabout non oxide glassand theirusage 4 9What arethe mainpositions inoxide glassesare there 4 10Why doesthe silicaplay soimportant rolein glasses 4 11How manytypes ofmain oxideand non oxide glassesare there 4 12What isthe mainusage forchalcogenide glasses 4 13How todecide whetherthe glassis amorphous 4 14What arethe temperaturesof Tgand Tm What informationcan weget fromthem 4 15What isthe coolingor quenchingrate Q Why isit importantduring the formation of glass 4 16How manyroles influencethepreparation of glass What problemsshould wehave toresolve with Please givesome examplesabout theways ofpreparationofglass 4 17What isthe structuremodels andbonding theoriesofglass What isthe differenceamong them 4 18What isthe chemical physical andoptical propertiesofglass What applicationcan bedone abouttheseproperties 4 19What isthe mainapplicationforglass How manyspecial kinds of glassesare there And howabout theirapplications 4 20What applicationswill theglass ownin optoelectronicfield 5Cement andConcrete Materials5 1What isPortland cement And whatis clinker 5 2How manytypes ofraw materialsfor producingcement arethere andwhat arethey 5 3What isthe purposeof fastcooling ofthe clinker 5 4What arechemical andmineralogical positionsof Portlandcement 5 5Please givea descriptionofthepropertiesofC3S C2S C3A andC4AF 5 6Analyze themajor factorsaffecting the rate of hydration 5 7Cite theorder oftherateofhydrationofthefour mineralphases C3S C2S C3A andC4AF in cement 5 8What isconcrete 5 9How manytypesofrawmaterialsinvolving in concrete production And whatare theirfunctions respectively 5 10Analyze themajor factorsaffecting concrete strength What istheprimaryfactor indetermining thestrength 5 11How doesconcretestrengthchange withtemperature Why 5 12Analyze theimportance ofaggregate cement pasteinterface 5 13What isdurability of concrete And how do youcharacterize the durability 5 14Cite themajor damagesof concretethat influencethedurability 5 15Which methodcould betaken intoaount onenhancing thefrost resistanceof concrete 5 16Aording toyour knowledge howdoyou achievea cement based materialwith veryhigh strength 5 17What arethe advantages of flyash tothepropertiesofconcrete 5 18How doeswater reducertake effectinconcrete 6Polymer Materials6 1What ispolymers 6 2What isthe mostsimple andmonly usednomenclature systembasedon 6 3What isthe inadequacyofthepreceding nomenclaturesystems 6 4Give abrief e