工程材料双语考试复习题.docx
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工程材料双语考试复习题.docx
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工程材料双语考试复习题
PARTITranslatethefollowingwordsortermsintoappropriateChinese(1point/term,1×10=10point)
1.metellurge
2.ferrousmetals
3.rare-earthmetals
4.stateofaggregation
5.crystallite
6.dislocation
7.stiffness
8.constitutionaldiagram
9.TTT-diagram
10.precipitation
PARTIIMatchthefollowingtermstoappropriatedefinitionorexpression(2point/term,2×5=10point)
a.toughness
b.ductility
c.hardness
d.impactstrength
e.strength
1thecapacityofamaterialtoundergodeformationundertensionwithoutruptureasinawiredrawingoperation
2theabilityofamaterialtoplasticdeformationusuallybyindentation
3theabilityofthematerialtosustainloadswithoutunderdistortionorfailure
4theabilityofamaterialtowithstandbendingortheapplicationofshearstresseswithoutfracture
5thestrengthofamaterialwhensubjectedtohighratesofloading,usuallyinbending,tensionortorsion
PARTIIExplainthefollowingwordsortermsinEnglishorinChinese(2point/term,2×10=20point)
1.austeniteasolidsolutionofcarboninγ-iron;
2.Cementiteisacompoundofcarbonandiron,Fe3C(ironcarbide).
3.solidsolutionWhenmolten,mostmetallicalloysemployedinindustryarehomogeneousliquids,i.e.liquidsolutions.Onpassingtothesolidstate,manyofthemretaintheirhomogeneity,andtherefore,solubility.Thesolidphasethatformsoncrystallizationofsuchanalloyiscalledsolidsolution.
4.allotropyTheexistenceofametal(substance)invariouscrystallineformsiscalledpolymorphic,orallotropic,modifications.
5.anisotropyThedifferenceinthepropertiesofcrystals,dependingonthedirectionoftest,iscalledanisotropy.
6.mechanicalmixture
7.degreeofundercoolingThedifferencebetweenthetheoreticalandactualtemperaturesofcrystsllizationiscalledtheamount,ordegree,ofundercooling.
8.Theprocessofeliminationofdistortionsinadeformedmetalduringheatingiscalledrecovery.
9.constitutionaldiagramTheconstitutionaldiagramisagraphicalrepresentationofthestateofanalloy.
10.Thesubstanceswhichformasystemarecalledconstituentsorcomponent.
11.Aphaseisahomogeneouspartofasystem,whichisseparatedfromtheotherparts(phases)byaninterfacesothatthecompositionandstructureofthesubstancechangejumpwiseonapassagethroughthatinterface.
12.Thenumberofdegreeoffreedom(variances)ofasystemisunderstoodasthenumberofexternalandinternalfactors(temperature,pressureandconcentration)whichcanbechangewithoutchangingthenumberofphasesinthesystem.
13.criticalcoolingrate
14.originalgrain
15.Gibbs’phaserule
ThegeneralrelationshipsforcoexistenceofthestablephaseswhichsatisfythetheoreticalconditionsofequilibriumcanbeexpressedmathematicallyinaformwhichhasbeennamedGibb’sphaserule.
Gibb’sphaseruleismathematicalexpressionoftheequilibriumconditionsforasystem,i.e.thephaseruleequationestablishesquantitativerelationshipbetweenthenumberofdegreeoffreedomcandthenumberofcomponentskandphasesfinasystem:
c=k–f+2.
16.crystallinestate
Anordered,regularpositionofparticles(atoms,molecules)inspaceischaracteristicofthecrystallinestateofasubstance.
thecrystallinestateischaracterizedprimarilybyanorderedregulararrangementofatomsinspace.
17.equillibriumdiagrams
Theconstitutionaldiagramshowsthestablestatesofanalloy,i.e.thosewhichhavetheleastfreeenergyundergivenconditions.Forthatreason,constitutionaldiagramsarecalledequilibriumdiagrams.
18.elementarycrystalcells
Thepositionofatomsinacrystalcanbeconvenientlydepictedintheformofspacearrangementswhicharecalledelementarycrystalcells.
19.Insomeinstances,thesimplesubstances-constituentsofanalloy-donotinteractchemicallywithoneanotherinthesolidstate.Thestructureofsuchanalloyisessentiallyamechanicalmixtureofparticlesorgrainsofthetwo(ormore)constituents.
PARTIIIFillinthemissingwordsortermsaccordingtothefollowingstatementsinEnglishorinChinese(1point/blank,25×1=25point)
1.Whenliquidmetaliscooled,itstemperaturedropsgraduallyandtheprocesscanbecalledsimplecooling,sinceitinvolvesnochangeinthestateofaggregation.
2.Therateofthewholecrystallizationprocessisdeterminedbytwofactors:
therateofnucleationtherateofcrystalgrowing.
3.Point1whichcorrespondstothebeginningofcrystallizationiscalledtheliquiduspoint,andpoint2,representingtheendofcrystallization,thesoliduspoint.
4.Thelocusoftheliquiduspointsiscalledtheliquiduslineandthatofsoliduspoints,thesolidusline.
5.Infirst-ordersystems,thetwoconstituentsareunlimitedlysolubleintheliquidstateandinsolubleinthesolidstateanddonotformchemicalcompounds.
6.Thetwoconstituentsareunlimitedlysolubleintheliquidandsolidstatesanddonotformchemicalcompouns.
7.Thetwocomponentsareinlimitedlysolubleintheliquidstate,limitedlysolubleinthesolidstateanddonotformchemicalcompounds.
8.Inthesolidstate,ironhastwomodifications:
α-Fe(b.c.c.lattice)andγ-Fe(f.c.c.lattice).
9.Twoelementaryprocessesofcrystallizationare()and().
10.Thestructureofacastingotconsistsofthreeprincipalzones.Thezonesare(),()and().
11.Inthemetalelements,thethreecommontypesofcrystallatticeare(),()and().
12.Whenasolidsolutionforms,itretainstheoriginalcrystallatticeof()element.
13.Permanentimpuritiesinallcommercialsteelsare(),(),(),()andgases.
14.Theiron-carbonalloyswithcarbonupto2.11percentarecalled()andthatwithcarbonover2.11percentarecalled().
15.Acircumstanceofprincipalsignificanceisthatα-ironcanexistwithintwotemperatureranges:
below()andfrom()to().
16.AnnealingisaprocedureofheattreatmentonwhichthesteelisheatedaboveAc3andthen(),fornormalizing,thecoolingiscarriedoutin().
17.Withchemicalheattreatingaseousphase(thecommonestcase),thetreatmentisbasedonthethreeelementaryprocesses:
(),()and().
18.Themethodofsurfacehardeningessentiallyconsistsinheatingandhardeningofthesurfacelayersonly.Theheatingcanbedonebytwocommonprocesses()and().
19.Ahigh-qualitystructuralmaterialshouldevidentlyhaveahighstrength,highreliability,andhighdurability.
11.Thestrengtheningeffectproducedinmetalsbyplasticdeformationiscalledstrain,orwork,hardening.
20.Apairofmovingdislocationscreateshundredsandhundredsofnewdislocationsandthusthedislocationdensityinthemetalincreasesandproducesthestrengtheningeffect(increasestheultimatestrength,Fig.3-25).
21.Aprocessofplasticworking(plasticdeformation)belowtherecrystallizationtemperatureiscalledcoldplasticworking.
22.Alloysmadepredominantlyofmetallicelementsandpossessingtypicalmetallicpropertiesarecalledmetallicalloys.
PARTIVAnswerthefollowingquestions(45point)
Methodsformetalstrengthening,whicharebasedonincreasingthedislocationdensity,havebeenknownforalongtime;theseincludemechanicalstrainhardening,refinementofgrainsandmosaicblocks,heattreatment.Besides,theknownmethodsofalloying(i.e.introducingforeignatomsintothemetallattice),whichformvariousimperfectionsanddislocationsofthecrystallattice,arealsointendedtoformobstaclestofreemovementofdislocations(lockingofdislocations).Theyalsoincludethemethodsofformingstructureswithwhatiscalledstrengtheningphaseswhichcauseprecipitationhardening.Allthese
Theprocessofrecrystallizationcanbedividedintotwostages:
primaryrecrystallizationduringwhichelongatedgrains,thathavebeendeformedbyplasticdeformation,aretransformedintofinerounded-offrandomlyorientedgrains;
secondaryrecrystallization(graingrowth)whichessentiallyconsistsinenlargementofgrainsizeandtakesplaceatahighertemperature.
Threevariousmechanismsmaybesuggestedtoexplaingraingrowth:
a)duetonucleation:
primaryrecrystallizationresultsinnucleationofcenterofnewcrystalsandthegrowthofthesecrystalsintheapperanceofnewgrains,thoughtheirnumberislessthanintheoriginalstateofthemetal,therefore,theywillbelargeontheaverageuponcompletionoftheprocess;
b)duetomigration:
agrainincreasesinsizeduetomigrationofitsboundary(Fig.3-34).Sincealargegrainisthermodynamicallymorestablethanafineone(hasalowerS/Vratio,whereSisthesurfaceareaandVisthevolume),largegrainsgrowfurtherbydevouringfinergrains;
c)duetograincoalescence:
i.e.grainboundariesaregraduallydissolvedandmanyfinegrainscombineintoalargegrain(Fig.3-35).
THETECHNOLOGYOFMETALSCOMPRISESTHETHREEBRANCHES:
(A)ENGINEERINGMETALLURGY,I.E.PRODUCTIONOFMETALSOFDESIREDCOMPOSITION;(B)MECHANICALMETALLURGY,I.E.SHAPINGOFMETALSAND(C)HEATTREATMENTFOROBTAININGDESIRABLEPROPERTIES.
Alltypesofheattreatmentcanbeclassifiedintofourmaingroups(accordingtoA.A.Bochvar)asfollows.
GroupI.Themetalmightbechangedtoanunstablestatebypriortreatment.Forinstance,coldplasticworkingcouldproduceworkhardening,i.e.distortionofthecrystallattice.Diffusionprocesseshavenotimetooccurduringsolidificationandthecompositionofthemetalisinhomogeneousevenwithinthevolumeofasinglegrain.Quickcoolingornonuniformstressesappliedcauseanonumiformdistributionofelasticstrain.Anunstables
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