材料導(dǎo)論課后習(xí)題-七章

Module7

7-1Understandthefollowingterms:（a）composites;（b）nanocomposites;（納

米復(fù)合材料）（c）environmentalcomposites.（環(huán)保復(fù)合材料）

（a）ausefulcomplexsolidmaterialcomposedoftwoormorematerialsthatarecombined

onamacroscopicscale（宏觀尺byphysicalmeansanddonotlosetheiridentity（特

性）.

（b）anewsubset（子集）ofCMC,MMCorPMC,arecompositeswithasubstrate（基板）that

isreinforced（加強(qiáng)）withnanometersizeparticles（微粒）thatenhance（提高）the

substrates'physicalproperties.

（c）acompositeconsistingof80%advancedpolymerand20%aluminum,developedfor

automotiveapplication,andeasilyrecycledandaremadeusinglowenergyandaclean

manufacturing（制造）system.

7-5WhatdotheabbreviationsCMC,PMCandMMCstandfor,respectively?

MMC:Metallicmatrixcomposites金屬基復(fù)合材料

PMC:Polymermatrixcomposites聚合物基復(fù)合材料

CMC:Ceramicmatrixcomposites陶瓷基復(fù)合材料

7-6Definethefollowingterms:（a）fiber-reinforcedcomposite;（b）fiber;（c）

whisker（晶須）;（d）continuousfiber（連續(xù)纖維）；（e）discontinuousfiber（間斷纖

維）;（f）criticallengthofafiber（纖維臨界長(zhǎng)度）

（a）amaterialssystemmadeprimarilyofvarying（不同）amountsofaparticularfiber

reinforcementembedded（嵌入）inaprotectivematerialcalledamatrix;acouplingagent

isappliedtothefibertoimprovetheadhesionofthefibertothematrixmaterial.

（b）thebasicindividualfilament（個(gè)別纖維）ofrawmaterialfromwhichthreadsor

fabrics（線程或面料）aremade.

（c）areformedfromextremelythinsinglecrystals（單晶）ofhighperfection（完善）witha

largelength-to-diameterratioforreinforcingcompositematerials.

（d）areessentially（基本上）infinite（無(wú)限）inlengthandextendcontinuouslythroughout

thematrixinacompositematerial.

（e）arenotlessthan3mminlengthandtendtoorient（方向）themselvesinthedirection

ofresinflowasacompositematerialisprocessed.

（f）Thelengthlimitforafibertohaveaload-carryingandreinforcingabilities（P332）

7-8Listthefunctionsofamatrixandacouplingagentinacomposite.

Thefunctionsofamatrixaretosupportandprotectthefibers,theprincipalload-carrying

agent（傳遞受力），andtoprovideameansofdistributingtheloadamongandbetweenthe

fiberswithoutitselffracturing.基體未破壞可分散均勻受力

Acouplingagentprovidesaflexiblelayer（層）attheinterface（界面）betweenfiberand

matrixthatwillimprovetheiradhesionandreducethenumberofvoidstrappedin（空隙

被困在）thematerial.

7-12Whenspeakingofinterfaceandinterphase,whichtermrepresentsthe

largerareaorvolumeinacompositematerial?Recallthedifferencebetween

thetwotermsinterfaceandinterphase.

Interphase界面相

Interfaceisasurfacethatformsacommonareaorboundarysimilarinmanyrespectsto

grainboundariesbetweenanytwoconstituents（成分）inamonolithic（單片）material.

Interphasesistheregionformedbetweentwointerfaces.Itisthereforeadistinctphasein

itselfwithitsownidentity（特性）/formingaregioncontiguoustotwophases.

7-13Sketchatypicalfiber-reinforcedcompositeandlabelthefollowing:

matrix,reinforcingfiber,interface,interphase.P335

Afiber-reinforcedcompositeisamaterialssystemmadeprimarilyofvaryingamountsofa

particularfiberreinforcementembeddedinaprotectivematerialcalledamatrix,acoupling

agentisappliedtothefibertoimprovetheadhesionofthefibertothematrixmaterial.

7-14Understandthedefinitionsoftheterms:（a）preimpregnation預(yù)浸漬；（b）

prepreg預(yù)浸料；（c）preforms（型坯）;（d）lamina（薄板）;（e）laminate;（f）bulk

moldingcompound（BMCs）｛塊（團(tuán)）狀模塑料｝;（g）sheetmoldingcompounds

（SMCs）（片狀模塑料）.

（a）FibercanbesaturatedwithresinousmateriaK纖維飽和樹(shù)脂）throughaprocesscalled

preimpregnation;

（b）Thepreimpregnatedfibersarecalledprepregs;

（c）Preformsarecustom-shaped定制成型，resin-bondedmats樹(shù)脂結(jié)合劑墊for

reinforcementofmoldedpartswithcomplexshapes.Inotherwords,apreformisabundle

纖維束offibershavingthedesiredvolumeandarchitecture量和結(jié)構(gòu)tofillamoldcavity

模具型腔foraone-shotmolding注射成型；

（d）aflatarrangementofunidirectionalfibersorwovenfibersinamatrix平面布置的單

向纖維或無(wú)紡布纖維基體；

（e）astackoflamina（一疊薄板）withvariousorientations（不同方向ofthedirections

oftheprincipalmaterials（主體材料）inthelamina;

(f)apremixedmaterialofshortfiberspreimpregnatedwithresinandvariousadditives預(yù)

混材料的短纖維預(yù)浸樹(shù)脂及各種添加劑

(g)sheetmoldingcompoundsareimpregnated,continuoussheetsofcompositematerial.

片狀模塑料浸漬，復(fù)合材料的連續(xù)的片

7-16Nametwotypesofglassfiber.Comparethemintermsoftheir

compositions,propertiesandapplications.

E-glass無(wú)堿玻璃纖維S-glass高強(qiáng)玻璃纖維

E-glassiscomposedof55%silica,20%calciumoxide,15%aluminumoxide,and10%

boronoxide.Itisthestandardgradeofglassusedinfiberglassandhasatensilestrength

ofabout3.45Gpaandhighresistivity.Fiberdiametersrangebetween3and20pm.55%

的二氧化硅，氧化鈣20%,15%的三氧化二鋁，10%氧化硼無(wú)堿玻璃纖維組成。它是在玻

璃纖維用玻璃的標(biāo)準(zhǔn)等級(jí)，并擁有約3.45GPa和高電阻率的拉伸強(qiáng)度。纖維直徑介于3至

20微米

S-glasswasdevelopedforhigh-tensile-strengthapplicationsintheaerospaceindustry.It

isaboutone-thirdstrongerthanE-glassandiscomposedof65%silicondioxide,25%

aluminumoxide,and10%magnesiumoxide.拉伸強(qiáng)度高，在航空航天工業(yè)應(yīng)用開(kāi)發(fā)的S-

玻璃。這是約三分之一比E玻璃和二氧化硅65%,25%的三氧化二鋁，氧化鎂10%組成。

7-17Whatisthestructureofaboronfiber?Whatistheproblemwhenboron

fibersareusedasreinforcementinanaluminummatrix?Listoneapproachto

overcomethisproblem.

課件

Problemswithchemicalreactionsbetweenboronandothermetalscontinuetobea

sourceofconcerntomaterialstechnologists.

OneapproachtothisproblemwasthecoatingoftheBORSICfiberwithsiliconcarbide,

whichprovidesafiberthatismorecompatiblewith(兼容，性)metal-matrixmaterials,

particularlyathighoperatingtemperatures.

7-18Comparecarbonandgraphitefibersintermsofmodulus,carboncontent

andpyrolyzing(裂解)temperature.Whichfibermaterialhasthegreater

specificmodulus?

Carbonfiberusuallyhasamodulusoflessthan344Gpaandacarboncontentbetween

80%and95%,Graphitefibershaveamodulusofover344Gpaandacarboncontentof

99%orgreater.Forcarbon,thistemperatureisaroundl315℃,andforgraphite,itis

around1900℃to2480℃.

Graphite

7-19Listatleasttwoprecursorsusedtoproducecarbonfibers.生產(chǎn)碳纖維的前

體好像是SiC(Siliconcarbide)andTiC(Titaniumcarbide)

7-26Whatarethefactorsinfluencingthestrengthofanindividual單獨(dú))fiber?

Theabsenceofsurfacedefects;Thepresenceofmicrocracksanywhereinthesmallfiber

causeslocalizedstressandloadconcentrationsandeventualfailureoftheindividualfiber.

任何地方在小纖維的表面缺陷的情況下，裂紋的存在導(dǎo)致局部構(gòu)造應(yīng)力和負(fù)載濃度和個(gè)別纖

維的最終失敗。

7-27Definiethefiber-aspectratio.Howdoesthestrengthofthecomposite

changewithincreasingtheratio?

Fiber-aspectratioisaratiooflength(L)todiameter(D)Theoptimumreinforcingfiberfor

acompositematerialhasaratiooflengthtodiameterofabout150.(最佳)

Thisratioincreasesthestrengthofthecompositeincreases.

7-28Definethetermsspecifictensilestrengthandspecificstiffness.

1.Specifictensilestrength:Theratioofthetensilestrengthofafibermaterialtoitsweigh

densityinKN/m3

2.Specificstiffness:Specificstiffness(orspecificmodulus)isaratioofthemodulusofelasticity

(ortensileelasticity)totheweightdensityofthefiber.

7-30Whatdoesfiberloadingreferto?Whatistherelationbetweenthe

strengthofthecompositesandthefiberloading?

Fiberloading(填充量):theamountofreinforcementinacompositematerial.

Thestrengthofthecompositeisdirectlyproportional(按比例)tothevolumeoffiber.

7-32UseequationstoexpresstheROMintermsofmodulusfortheisostrain

situationandtheinverseROMintermsofmodulusfortheisostresssituation.

Givetwoassumingconditionsforisostrainloading.舉兩個(gè)isostrain加載的假設(shè)條件

課件

1:E(C)=E(f)V(f)+E(m)V(m)

2.e(c)=e(f)+e(m)

7-34Listsomefatigue-failurecharacteristicsofFRP.

l.Agradualdecrease（逐漸減少）intheslopeofthestress-straincurveoccursduring

cyclicloading.

2.Elevatedtemperatures（高溫）normallyreducetheperformanceofmatrix-dominated

（基體為主）composites.Fiberfatiguepropertiesarebetterthanthoseofthepolymer

matrix.

3.Moistureandchemicalexposure（水分和化學(xué)物質(zhì)影響）cangreatlyaffectthepolymer

matrix.

4.Notch（缺口）sensitivityinhigh-cycletensile-fatigueconditionsislessthanformetals.

5.Thereareconsiderablyfewer（相當(dāng)少）matrix-dominatedpropertiesthan

fiber-dominatedproperties.Hence（因止匕）tensile,compressive（抗壓）,andshearstresses

intheinterlaminardirection（層間方向），beingmatrixdominated（基體為主）zshouldbe

kepttoaminimum（最低限度）.

7-35Whatdoesfracturetoughness（斷裂韌性）referto?

Inunitsofstresstimesthesquarerootofacracklength,isanindicatorof（指標(biāo)）a

material'sresistancetotheextension（延彳申）ofapreexisting（先前存在）crack,

7-37Classifythecompositesbasedonmatrixandthegeometry（幾何形狀）of

reinforcement.

Fiber（纖維）/aminated（疊層）,sandwich（夾層）/particulate（顆粒）zflake（片狀），

filled（填補(bǔ)），hybrid（混雜），foam（泡沫）.

7-38WhatdoesGRPstandfor?Listsomeoftheadvantagesandapplications

ofGRPs.

GRP:glass-reinforcedplastics玻璃增強(qiáng)塑料

Goodbalanceofproperties;highcorrosionresistance;lowincost;amultitude（大量）

ofusesinstructural,industrialandconsumer-relatedproducts;ranginginsizefromminute

circuitboardstoboathulls（船體）

可用作fiberand汽車(chē)玻璃

7-39Whataretheadvantagesanddisadvantagesofcarbon/carbon

composites?Listsomeapplicationsofcarbon/carboncomposites.

1.Lightweight（density:1.3g/cm3）2.Strongerathightemps,thanatlowtemps.

3.Highspecificstrength比強(qiáng)度4.Goodresistancetothermalshock耐熱沖擊性

5.Self-lubricating自潤(rùn)滑6.Electricalproperties

7.Limitation:oxidation,limitsthehightemperatureapplications?Solution:SiCcoating｛氧

化高溫使用限制解決方案SiC涂層｝

7-45Whatisalaminarcomposite?Giveseveralexamplesoflaminar

composites.

Laminarcomposite:consistoflayersofatleasttwodifferentsolidmaterialsbonded

togethersothatthefiberorientation(方向)runsatdifferentangles.

Cladmetals,safetyglass,graftskin,rigidlaminates,包鋼金屬，安全玻璃，皮膚移植，剛性

層壓板

7-47Sandwichcompositesusuallyhavefacingmaterialsandcoresofvarious

configurations.Pleaselistseveralfacingmaterialsandsomecoreforms.

Facingmaterials:面材aluminum,wood,vinyl,paper,glass-reinforcedplastics,and

stainlesssteel.

Corematerials:芯材cellularinformandtakeontheconfigurationsknowashoneycomb

蜂窩狀，waffle華夫餅狀，corrugated波紋狀，tubeandcone管狀和錐狀.

7-51Whydocarbonblackshavereinforcingeffectwhenusedasinexpensive

reinforcingfillersintires?

WhenusedforreinforcingfillersItires,carbonblackenhancesthetensilestrength,

toughnessandwearresistance.Itsreinforcingeffectonsuchpropertiesistheresultofits

particularlygoodadhesivebonding.(P367)

7-52Whatisahybridcomposite?Listthefourbasictypesofhybrids.

Hybridcomposites:differentfibersinacommonmatrix,greatlyexpandtherangeof

propertiesthatcanbeachievedwithadvancedcomposites.

interply層間混雜，intraply層內(nèi)混雜，interply/intraply層間/層內(nèi)混雜，superhybrids超混雜

7-59Understandthethreekindsofclosedmoldingmethods:compressing

molding,injectionmolding;resintransfermolding.

Compressionmolding模壓成型：useTSresinsplacedinacavityofamatchedmoldinthe

openposition.

Injectionmolding注射模塑：isusedtoformmoltenthermoplasticandthermosetting

matrixinaclosedmold,wheretheyarehelduntilthematerialssolidify.

轉(zhuǎn)移模塑ResinTransfermolding:differsfromRIMinthatareinforcementismoldedwith

theresin,however,theequipmentisbasicallythesame.

7-66Understandthecompositefabrication制作methodofpultrusion拉擠.

Acompositefabricationmethodbywhichanextremelylong,fiber-reinforced,

polymer-matrixmaterialcanbeproducedbypullingafiberorabundleofcontinuous

filamentsthrougharesinsystemforimpregnationandthenthroughaheatedcuringdie.

附加題

l.Howistheorientationoffiberrelatedtofiberloadingandprocessingmethodsof

composites?

1.Maximumloadofabout85%?allfibersplacedparalleltoeachother最大負(fù)荷的85%

左右?所有纖維平行放置彼此

2.Between50and75%loadrange?halfofthefibersarrangedatrightanglestoeach

other50至75%負(fù)載范圍?一半安排在合適的纖維對(duì)對(duì)方的角度

3.Arangeofonly15to50%?arandomarrangement(choppedstrands)一個(gè)只有15

至50%范圍內(nèi)?隨機(jī)安排(短切原絲)

2.