A Transforming Metal Nanocomposite with Large Elastic Strain, Low

A Transforming Metal Nanocomposite with Large Elastic Strain, LowModulus, and High StrengthShijie Hao et al.

Science 339, 1191 (2013);

DOI: 10.1126/science.1228602

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initiallyalignedwiththisdirectionemittedpurecircularlypolarizedphotonsandremainedin-variantunderscattering.Theirsuperpositions,ontheotherhand,becameentangledwiththescat-teredphotonpolarization.Statesthatareinvariantundercouplingtotheenvironmentareofinterest,notonlybecauseoftheirimportanceinthequan-tummeasurementprocessbutalsobecauseoftheirpotentialuseforquantumcontrolpurposes.Invariantstatescanspandecoherence-freesub-spacesinwhichquantuminformationcanbeprotected(21).Itwouldbethereforeinterestingtosearchformulti-spinstatesthatareinvariantunderphotonscattering,anddetection,byusinglargerarraysoftrappedions.

ReferencesandNotes

1.W.H.Zurek,Rev.Mod.Phys.75,715(2003).2.Thismechanismisdifferentthantheprocessof

ein-selectionindecoherencetheory,inwhichthemutualinteractionbetweenaquantumsystem,ameasurement

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apparatus,andtheirenvironmentresultsintheemergenceofapreferredbasis(1).

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M.S.Chapmanetal.,Phys.Rev.Lett.75,3783(1995).M.Mei,M.Weitz,Phys.Rev.Lett.86,559(2001).D.A.Kokorowski,A.D.Cronin,T.D.Roberts,D.E.Pritchard,Phys.Rev.Lett.86,2191(2001).R.Ozerietal.,Phys.Rev.Lett.95,030403(2005).H.Uysetal.,Phys.Rev.Lett.105,200401(2010).N.Akerman,S.Kotler,Y.Glickman,R.Ozeri,Phys.Rev.Lett.109,103601(2012).

D.B.Hume,T.Rosenband,D.J.Wineland,Phys.Rev.Lett.99,120502(2007).

A.H.Myersonetal.,Phys.Rev.Lett.100,200502(2008).A.Keselman,Y.Glickman,N.Akerman,S.Kotler,R.Ozeri,NewJ.Phys.13,073027(2011).

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J.Volzetal.,Phys.Rev.Lett.96,030404(2006).N.Akerman,S.Kotler,Y.Glickman,A.Keselman,R.Ozeri,App.Phys.B,10.1007/s00340-011-4807-6(2011).

MaterialsandmethodsareavailableassupplementarymaterialsonScienceOnline.

18.Cohen-Tannoudji,ClaudeandDiu,BernardandLaloe,

Frank,QuantumMechanics(Wiley-Interscience2006),Vol.2,p.1048.

19.M.A.Nielsen,I.L.Chuang,QuantumComputationand

QuantumInformation(CambridgeUniv.Press,Cambridge,2000).

20.M.B.Plenio,S.Virmani,put.7,

1(2007).

21.D.A.Lidar,I.L.Chuang,K.B.Whaly,Phys.Rev.Lett.81,

2594(1998).Acknowledgments:Y.G.andS.K.haveequallycontributedtothiswork.WethankN.DavidssonandD.Stamper-Kurnforusefulcommentsonthemanuscript.Wegratefully

acknowledgethesupportbytheIsraeliScienceFoundation,theMinervaFoundation,theGerman-IsraeliFoundationforscientificresearch,theCrownPhotonicsCenter,andM.KushnerSchnur,Mexico.

SupplementaryMaterials

/cgi/content/full/339/6124/1187/DC1MaterialsandMethodsFigs.S1toS4

3September2012;accepted2January201310.1126/science.1229650

17.

ATransformingMetalNanocompositewithLargeElasticStrain,LowModulus,andHighStrength

ShijieHao,1LishanCui,1*DaqiangJiang,1XiaodongHan,2*YangRen,3*JiangJiang,1

YinongLiu,4ZhenyangLiu,1ShengchengMao,2YandongWang,5YanLi,6XiaobingRen,7,8XiangdongDing,7ShanWang,1CunYu,1XiaobinShi,1MinshuDu,1FengYang,1YanjunZheng,1ZeZhang,2,9XiaodongLi,10DennisE.Brown,11JuLi7,12*

Freestandingnanowireshaveultrahighelasticstrainlimits(4to7%)andyieldstrengths,

butexploitingtheirintrinsicmechanicalpropertiesinbulkcompositeshasproventobedifficult.Weexploitedtheintrinsicmechanicalpropertiesofnanowiresinaphase-transformingmatrix

basedontheconceptofelasticandtransformationstrainmatching.ByengineeringthemicrostructureandresidualstresstocouplethetrueelasticityofNbnanowireswiththepseudoelasticityofaNiTishape-memoryalloy,wedevelopedaninsitucompositethatpossessesalargequasi-linear

elasticstrainofover6%,alowYoung’smodulusof~28gigapascals,andahighyieldstrengthof~1.65gigapascals.Ourelasticstrain-matchingapproachallowstheexceptionalmechanicalpropertiesofnanowirestobeexploitedinbulkmaterials.tischallengingtodevelopbulkmaterialsthatexhibitalargeelasticstrain,alowYoung’smodulus,andahighstrengthbecauseoftheintrinsictrade-offrelationshipsamongtheseprop-erties(1,2).AlowYoung’smodulusinasingle-phasematerialusuallymeansweakinteratomicbondingandthuslowstrength.Becauseoftheinitiationofdislocationactivityand/orearlyfail-urecausedbystructuralflaws,theelasticstrainofbulkmetalsisusuallylimitedtolessthan1%.Becausefreestandingnanowireshaveultrahighelasticstrainlimits(4to7%)andyieldstrengths(3–9),itisexpectedthatcompositesmadewithnanowireswillhaveexceptionalmechanicalprop-erties.However,theresultsobtainedsofarhavebeendisappointing(10),primarilybecausethein-trinsicmechanicalpropertiesofnanowireshavenotbeensuccessfullyexploitedinbulkcomposites(10–12).AtypicalexampleistheNbnanowire–Cumatrixcomposite,inwhichthenanowiresare

nanowires,asillustratedinFig.1A.Second,SIMTanddislocationsliparefundamentallydifferentprocessesattheatomicscale.Whereastheinelasticshearstrainbetweentwoadjacentatomicplanesapproaches100%afterdislocationslip(17),theatomic-levelinelasticortransformationstrainis~10%afterSIMTintypicalSMAssuchasNiTi(16).Therefore,inelasticstrainincompatibilities(whichmustbecompensatedforbytheelasticstrainfieldtomaintaincohesion)aremuchmilderattheSMA-nanowireinterfacethanattypicaldislocation–piled-upinterfaces.

Toverifythishypothesis,weselectedNbnanowirestobecombinedwithaNiTiSMA.TheNiTi-Nbsystemwith~20atomic%Nbun-dergoeseutecticsolidificationintoamicrostruc-tureconsistingoffineNblamellae(18),whichcanbeconvertedintoNbnanowiresthroughse-vereplasticdeformation.Inthisstudy,aningotwithacompositionofNi41Ti39Nb20(atomic%)waspreparedbymeansofvacuuminduction

StateKeyLaboratoryofHeavyOilProcessing,ChinaUni-versityofPetroleum,Beijing102249,China.2InstituteofMicrostructureandPropertiesofAdvancedMaterials,BeijingUniversityofTechnology,Beijing100124,China.3X-raySci-enceDivision,ArgonneNationalLaboratory,Argonne,IL60439,USA.4SchoolofMechanicalandChemicalEngi-neering,TheUniversityofWesternAustralia,Crawley,WA6009,Australia.5StateKeyLaboratoryforAdvancedMetalsandMaterials,UniversityofScienceandTechnologyBeijing,Beijing100083,China.6SchoolofMaterialsScienceandEn-gineering,BeihangUniversity,Beijing100191,China.7StateKeyLaboratoryforMechanicalBehaviorofMaterialsandFrontierInstituteofScienceandTechnology,Xi’anJiaotongUniversity,Xi’an710049,China.8FerroicPhysicsGroup,NationalInstituteforMaterialsScience,Tsukuba,305-0047Ibaraki,Japan.9StateKeyLaboratoryofSiliconMaterials,ZhejiangUniversity,Hangzhou310058,China.10DepartmentofMechanicalEngineering,Uni-versityofSouthCarolina,Columbia,SC29208,USA.11Depart-mentofPhysics,NorthernIllinoisUniversity,DeKalb,IL60115,USA.12DepartmentofNuclearScienceandEngineeringandDepartmentofMaterialsScienceandEngineering,Massachu-settsInstituteofTechnology,Cambridge,MA02139,USA.*Towhomcorrespondenceshouldbeaddressed.E-mail:lishancui63@(L.C.);xdhan@(X.H.);ren@aps.anl.gov(Y.R.);liju@mit.edu(J.L.)

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welldispersedandwellaligned,withstronginter-facialbonding.TheelasticstrainlimitachievedintheNbnanowiresinthistypeofcompositeisonly~1.5%(13,14),farbelowwhatmaybeex-pectedoffreestandingnanowires(3–9).

Tooptimizetheretentionofnanowireprop-ertiesinacomposite,wehypothesizethatthematrixshouldnotdeformviasharpmicroscopicdefectssuchascracksordislocationsbutrathershouldberubberyorgluelike,whichsuggeststheuseofashape-memoryalloy(SMA)asthematrix.TherearetwomaindifferencesbetweenanSMAmatrixandaconventional,plasticallyde-formingmetalmatrix.First,macroscopically,SMAsupportsalargepseudoelasticstrainof~7%bystress-inducedmartensitictransformation(SIMT)(15,16),whichisastrainmagnitudecomparabletonanowireelasticity(3–9).UseofanSMAasthematrixallowsonetomatchthehighpseudo-elasticityoftheSMAwiththehighelasticityof

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melting(fig.S1).Macroscopicwiresoftheinsitucomposite(nanowireinsitucompositewithSMA,hereinafterreferredtoasNICSMA)withdiametersof0.3to1.0mmweresubse-quentlyfabricatedbyforging,wire-drawing,andannealing(Fig.1B)(19).Thetypicalmicro-structureofNICSMA(Fig.1,CtoE)consistsofNbnanowiresformedinsituwithameandiameterof60nm,welldispersedandwellalignedintheNiTimatrixalongthewireaxialdirection,withwell-bondedinterfaces.Theselected-areaelectrondiffraction(SAED)pattern(Fig.1F)isindexedtobody-centeredcubicNbandB2-NiTiphases.Thephasecomponentsofthecompositewerefur-thercharacterizedbyhigh-energyx-raydiffrac-tion(HE-XRD)(fig.S2)andenergy-dispersivex-rayspectroscopicanalysis(fig.S3).BothSAEDandHE-XRDdemonstratethattheNbnanowiresarewellorientedwithits[110]directionparalleltothewireaxialdirection.Figure1,GandH,showsthemorphologiesoffreestandingNbnanowiresobtainedbyremovingtheNiTimatrixviaelec-trolyticetching(fig.S4),revealingthattheNbnanowireshavelengthsrangingfrom1to100mmandameanaspectratioexceeding100.

InsitusynchrotronHE-XRD(fig.S5)wascarriedoutonNICSMAatroomtemperature.TheevolutionofthediffractionpeaksforB2-NiTi(211)andB19′-NiTi(001)(fig.S6)indicatesthattheNiTimatrixunderwentanelasticdefor-mationfollowedbySIMTduringtensileload-ing.Figure2Ashowstheevolutionofd-spacingstrainwithrespecttotheappliedmacroscopicstrainfortheNb(220)planeperpendiculartotheloadingdirection,illustratingthattheNbnanowiresexhibitedatensileelasticstrainof4.2%whenembeddedintheSIMTmatrix.ThiselasticstrainlimitoftheNbnanowiresiscom-parabletothatoffreestandingnanowires(3–9).Furthermore,theelasticstrainlimitsofthenano-wiresembeddedintheSIMTmatrixincreasegraduallywithdecreasingnanowirediameter.ThemaximumelasticstrainlimitoftheNbnano-wiresobserved(fig.S7)was6.5%(theredcurveinFig.2A).Incontrast,wefoundthat,whenevertheNiTimatrixdeformedbydislocationslipin-steadofbySIMTaftertheinitialelasticdefor-mation(fig.S8),theelasticstrainlimitsoftheNbnanowiresaregreatlyreducedto~1.3%(theblackcurveinFig.2A).Figure2Bshowsacom-parisonoftheelasticstrainlimitsof(a)Nbnano-wiresinthematrixdeformingbydislocationslip(13,14,20–22),(b)NbnanowiresinthematrixdeformingbySIMT,and(c)somefreestandingnanowires(3–9).

Afterpretreatmentwithatensilestraincy-cleof9.5%,thebulkNICSMAexhibitedalargequasi-linearelasticstrainofover6%,alowYoung’smodulusof~28GPa,andahighyieldstrengthofminimum1.65GPawithinthetem-peraturerangeof15°to50°C(Fig.3,AandB).IncomparisonwithotherknownbulkmetalswithlowYoung’smoduli—forexample,Mg,Al,andTialloysandgummetals(1,2,23,24)—theyieldstrengthofNICSMAissuperior.Figure3,Cand

D,showsgeneralcomparisonsoftheelasticstrainlimit,Young’smodulus,andyieldstrengthofNICSMAandothermetals(1,2,23–25)andhu-manbones(23).NICSMAoccupiesauniquespot

onachartofthemechanicalpropertiesofvariousbulkmaterials(fig.S9)andpossessesgoodcyto-compatibility(figs.S10andS11)andcorrosionre-sistanceinaphysiologicalenvironment(fig.S12).

Fig.1.(A)SchematicofthedesignconceptofNICSMA.Schematictensilestress-straincurvesofahigh-strengthmetallicnanowire(I),anSMA(II),andaNICSMA(III).(B)AcoilofNICSMAwirewithadiameterof0.5mm.(C)Transmissionelectronmicroscopy(TEM)imageofalongitudinalsectionofNICSMAwire.NWindicatesnanowire.(D)ScanningTEMimageofthecrosssectionofNICSMAwire(brightregions,crosssectionsofNbnanowires;darkregions,NiTimatrix).(E)High-resolutionTEMimageoftheinterfacebetweentheNbnanowireandtheNiTimatrix.(F)SAEDpatternfromalongitudinalsectionofNICSMAwire.(G)MacroscopicappearanceofabundleoffreestandingNbnanowires.(H)ScanningelectronmicroscopyimageofthefreestandingNbnanowires.

AB

Fig.2.Elasticstrainlimitsofnanowires.(A)Evolutionofthed-spacingstrainwithrespecttotheappliedmacroscopicstrainfortheNb(220)planeperpendiculartotheloadingdirectionintheNICSMAwiresinwhichtheNiTimatrixdeformedbySIMTanddislocationslip.Thegreencurve(withamaximumstrainof4.2%)correspondstothesampleshowninFig.1with60-nm-diameterNbnanowires.Theredcurve(withamaximumstrainof6.5%)correspondstoadifferentsample(fig.S7),withevennarrowerNbnanowires.(B)Comparisonoftheelasticstrainlimitsof(a)Nbnanowiresembeddedinthematrixdeformingbydislocationslip(13,14,20–22),(b)NbnanowiresembeddedinthematrixdeformingbySIMT,and(c)somefreestandingnanowires(3–9

).

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Fig.3.TypicalmacroscopicmechanicalpropertiesofNICSMA.(A)Tensilestress-straincurvesofapre-treatedNICSMAat15°,30°,and50°C.sS,yieldstrength;E,Young’smodulus;ee,elasticstrainlimit.(B)Cyclictensilestress-straincurvesofapretreatedNICSMAatroomtemperature.(C)Comparisonoftheyieldstrengthsandelasticstrainlimitsofdif-ferentmaterials.(D)ComparisonoftheyieldstrengthsandYoung’smoduliofdifferentmaterials.

A

B

C

D

AC

D

B

E

Fig.4.MicroscopicresponsesofNICSMArevealedbyinsitusynchrotronHE-XRD.(A)Evolutionofthed-spacingstrainforNb(220)andB2-NiTi(211)planesperpendiculartotheloadingdirectionduringthepretreat-ment.(Inset)Themacroscopicstress-straincurveofthepretreatment.(B)EvolutionofthediffractionpeaksofNb(220),B2-NiTi(211),andB19′-NiTi(001)duringthepretreatment.(C)Evolutionofthed-spacingstrainforNb(220)planeperpendiculartotheloadingdirectionduringthesubsequenttensilecycle.(Inset)Thecyclicstress-straincurve.(D)

tiveintensityoftheB19′-NiTi(001)diffractionpeakduringthesubsequenttensilecycle.TherelativeintensityisdefinedastheratiooftheintegratedareaoftheB19′-NiTi(001)diffractionpeakatagivenappliedstraintothatoftheB19′-NiTi(001)diffractionpeakatthemaximumappliedstrain.(E)EvolutionofthediffractionpeaksofNb(220),B2-NiTi(211),andB19′-NiTi(001)duringthesubsequenttensilecycle.TheB2-versus-B19′peakintensitychangescontinuously,indicatingcontinuousSIMTthroughoutthetensileloading.VOL339

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InsitusynchrotronHE-XRDwasusedtocharacterizethedeformationandphasetransfor-mationevolutionsoftheNbnanowiresandtheNiTimatrix,duringthepretreatment(Fig.4A,inset)andthesubsequenttensilecycle(Fig.4C,inset).Afterthepretreatment,theNbnanowiressustainedanelasticcompressivestrainof–1.4%(pointD),whereastheNiTimatrixsustainedanelastictensilestrainof1%(pointE)(Fig.4A).ThereisalsosomeretainedB19′phaseinthematrix(Fig.4B).Theseresultscanbeunderstoodasfollows.Uponremovalofthepretreatmentload,theplasticallydeformedNbnanowires(AtoBinFig.4A)hinderedtherecoveryoftheNiTimatrixbecauseoftheB19′→B2transfor-mation(15,16),whichcausedlargeresidualstrainsinthenanowiresandtheSMAwithsomeretainedB19′phase.Thisdemonstratesthatstrongcouplingbetweenthenanowiresandthematrixtookplaceduringthepretreatment.Inthesubse-quenttensilecycle(Fig.4C),theelasticstrainachievedintheNbnanowireswasupto5.6%(AtoB),consistingofthepreexistingelasticcompressivestrainof–1.4%(OtoB)andanelastictensilestrainof4.2%(OtoA).TheNiTimatrixwentthroughcontinuousSIMTthrough-outthetensileloadingandexhibitedanultralowtangentialeffectivemodulus(Fig.4,DandE)ratherthanundergoinganinitialelasticdefor-mationfollowedbyanabruptSIMTtransition,aswouldoccurinamonolithicSMA(16).ThecontinuousSIMTcanbeascribedtothecontri-butionofthepreexistinginternaltensilestressandtheretainedB19′phaseinthematrix.Uponunloading,theNiTimatrixunderwentareversetransformationfromthestress-inducedmartens-itetotheparentphase(Fig.4,DandE),in-troducingasmallhysteresisinthestress-straincurveresultingfromenergydissipationduringtheprocess.TheexperimentalevidencepresentedabovedemonstratesthattheNbnanowiresex-periencedanultrawideelasticstrainof4.2%–(–1.4%)=5.6%,whichcloselymatchesthephasetransformationstrainof~7%ofNiTi.ThismatchingofelasticandtransformationstrainsresultsintheextraordinarypropertiesofNICSMA.

ReferencesandNotes

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689(2006).

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A.Misra,Appl.Phys.Lett.94,031906(2009).

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042503(2007).

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25.D.C.Hofmannetal.,Nature451,1085(2008).Acknowledgments:WethankG.H.Wu,H.B.Xu,andY.F.ZhengforvaluablediscussionsonthedeformationmechanismofNICSMA.ThisworkissupportedbythekeyprogramprojectofNationalNaturalScienceFoundationofChina(NSFC)(51231008),theNational973programsofChina(2012CB619400and2009CB623700),andthe

NSFC(51071175,51001119,50831001,and10825419).J.L.alsoacknowledgessupportbyNSFDMR-1008104andDMR-1120901.X.D.H.acknowledgessupportbytheBeijingHigh-levelTalents(PHR20100503),theBeijingPXM201101420409000053,andBeijing211project.

D.E.B.acknowledgessupportbytheInstituteforNanoScience,Engineering,andTechnology(INSET)ofNorthernIllinois

eoftheAdvancedPhotonSourcewassupportedbytheU.S.DepartmentofEnergy,OfficeofScience,undercontractno.DE-AC02-06CH11357.

SupplementaryMaterials

/cgi/content/full/339/6124/1191/DC1MaterialsandMethodsFigs.S1toS12References(26–30)

9August2012;accepted10January201310.1126/science.1228602

TerrestrialAccretionUnderOxidizingConditions

JulienSiebert,1*JamesBadro,2DanieleAntonangeli,1FrederickJ.Ryerson2,3

Theabundanceofsiderophileelementsinthemantlepreservesthesignatureofcoreformation.

Onthebasisofpartitioningexperimentsathighpressure(35to74gigapascals)andhightemperature(3100to4400kelvin),wedemonstratethatdepletionsofslightlysiderophileelements(vanadiumandchromium),aswellasmoderatelysiderophileelements(nickelandcobalt),canbeproducedbycoreformationundermoreoxidizingconditionsthanpreviouslyproposed.Enhancedsolubilityofoxygeninthemetalperturbsthemetal-silicatepartitioningofvanadiumandchromium,precludingextrapolationofpreviousresults.WeproposethatEarthaccretedfrommaterialsasoxidizedasordinaryorcarbonaceouschondrites.Transferofoxygenfromthemantletothecoreprovidesamechanismtoreducetheinitialmagmaoceanredoxstatetothatofthepresent-daymantle,reconcilingtheobservedmantle

vanadiumandchromiumconcentrationswithgeophysicalconstraintsonlightelementsinthecore.hedepletionofsiderophile(i.e.,“iron-loving”)elementsinEarth’smantlerelativetochondritescanconstraintheredoxstateofaccretingmaterialsduringterrestrialaccretionandcoredifferentiation(1–4).Forexample,metal-InstitutdeMinéralogieetdePhysiquedesMilieuxCondensés,UniversitéPierreetMarieCurie,UMRCNRS7590,InstitutdePhysiqueduGlobedeParis,75005Paris,France.2InstitutdePhysiqueduGlobedeParis,UniversitéParisDiderot,75005Paris,France.3LawrenceLivermoreNationalLaboratory,Livermore,CA94551,USA.

*Towhomcorrespondenceshouldbeaddressed.E-mail:julien.siebert@impmc.upmc.fr

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silicatepartitioningexperimentsatatmospher-icpressureindicatethattheobserveddepletionofslightlysiderophileelements(SSEs)suchasVandCrcanonlybeproducedatconditionsmorereducingthanthoserequiredtoaccountfortheabundanceofmoderatelysiderophileelements(suchasNi,Co,andW)orhighlysiderophileele-ments(5).Usingmetal-silicatepartitioncoefficientsobtainedatpressuresupto25GPa,homogeneousaccretionmodelspositthatmetal-silicateequilib-riumtookplaceatthebaseofadeepterrestrialmagmaoceanatasingleoxygenfugacity(fO2)(6–8).However,thepressure-temperature(P-T)

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conditionsrequiredtoproducetheobservedde-pletionsforVandCr(atthepresent-dayfO2)requiretemperaturesthatgreatlyexceedthatofthemantleliquidus(2,4,9,10).Suchcondi-tionsarephysicallyinconsistentwiththemagmaoceanhypothesis,wheretheP-Tconditionsatthebaseofamagmaoceannecessarilyliebe-tweenthemantlesolidusandliquidus,therebycreatingarheologicalboundarythatenablesthemetaltopondandequilibratewiththesilicatemelt.TosatisfythisrheologicalconstraintandSSEabundancepatterns,recentmodelsofcorefor-mationconstrainmetal-silicateequilibrationtotheP-TconditionsoftheperidotiteliquidusandinvokeearlyaccretionofhighlyreducedmaterialswithaFeO-poorsilicatecomponent(2,4,10,11).TheseinitiallylowfO2conditions(~IW-4,cor-respondingto4logfO2unitsbelowtheiron-wüstitebuffer)enhancethesiderophilecharacteroftheSSEsattherelevantP-Tconditions.Subsequent,gradualoxidationofthemantleto~IW-2overthecourseofcoreformationisre-quiredtoaccountformoderatelysiderophileele-mentabundancesand,mostimportant,toreachthecurrentmantleFeOcontent[8weightpercent(wt%)FeOinsilicate].Underreducingcon-ditions,siliconislikelytobetheonlylightele-mententeringthecoreinlargeamounts(10–12).ThisscenarioreliesonextensivepressureandtemperatureextrapolationofSSEpartitioningdata,asexistingresultsarerestrictedtorela-

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