DOC

Mn-Ga ferromagnetic shape memory alloy particles prepared by ball milling

By Stacy Simmons,2014-12-15 04:35
24 views 0
Mn-Ga ferromagnetic shape memory alloy particles prepared by ball milling

    Mn-Ga ferromagnetic shape memory

    alloy particles prepared by ball milling Science

    PressTrans.NonferrousMet.Soc.China17(20071s614s617

    Transactionsof

    NonferrousMetals

    SocietyofChina

    www.CSU.edu.cn/ysxb/

    StructuraltransitionofNi?-Mn?-Gaferromagneticshapememory

    alloyparticlespreparedbyballmilling

    CHENFeng(~,),TIANBing(),LILi(李莉),ZHENGYufeng(郑玉峰)

    CenterforBiomedicalMaterialsandEngineering,

    HarbinEngineeringUniversity,

    Harbin150001,China

    Received15July2007;accepted10September2007

    Abstraet:Thesize,crystalstructureandphasetransformationofNi498Mn28sGa217alloyparticlespreparedbyplanetarybal1milling

    (PBM)andvibrationbal1milling(VBM)wereinvestigatedbvSEM.XRDandDSC.Theresultsshowthattheparticlesmilledbv

    PBMfor4hexhibitirregularpolyhedron,withthesizedistributionbetween5gmand40/am.Theseparticlespresentdisorderedfet

    structurewithnophasetransformationbehaviour.Whenannealedat600?

    for1h.thecrysta1structureoftheparticlesevolvesfrom

    disorderedfettoHeuslercompletely.TheparticlesmilledbvVBMfor4hexhibitnakvshape.withthesizedistributionfrom3Ixm

    to30/am.Theparticlespresentdisorderedfeestructurewithnophasetransformationbehaviour.Howeverthecrysta1structureof

theseparticlesdoesn'ttransforlTlfromdisorderedfeetoHeuslercompletelyafterannealinga

    t600?for1h.forthesevere1attice

    distortioninducedintheVBMprocessisnoteliminatedentirely. Keywords:Ni-?Mn?-Gaalloyparticles;structuraltransition;phasetransformation;ballmill

    ing

    1lntroduction

    Ni..Mn..Gaferromagneticshapememoryalloyshave drawnmuchattentionfortheirlargemagneticfield inducedstrainuDtO10%andhighresponsespeedin magneticfield[13].Themagneticshapememory

    behavior,martensitictransformation,magneticproperties, andsoon,havebeenextensivelystudied[461.Though

    somanypropertiesofthebulkNi..Mn..Gaalloyshave beenstudiedsystematically,asweknow,thebrittleness ofpolycrystallineandsinglecrystallinebulkalloys stronglylimitthepracticaluseforNiMnGaalloys.To

    overcomethisproblem,thethinfilms,meltspunribbons

    andparticles/polymercompositematerialshavebeen studiedwidely[710].Theparticles/polymercomposite approachisaverysimpleandeffectivemethOdfor reducingbrittlenessandachievingtheshapewedesired. However,thefabricationofNiMnGaparticlesis

    seldomreported,exceptthatthemagnetic

    properties[1l12]andmagnetocaloriceffect[13]of

    Ni..Mn..Gafineparticlespreparedbysparkerosion methodhavebeenstudied.

    Ballmillingmethodismorecosteffectivethan

    sparkerosionmethodforpreparingalloyparticles.Inthis study,twotypesofNi498Mn285Ga217microparticles

    werepreparedbyplanetaryandvibrationballmilling

    methods,respectively,andtheirstructuraltransitionwas studied.

    2Experimental

    ApolycrystallineingotofNi498Mn285Ga217alloy waspreparedbyarcmeltingfumaceunderargon

    atmosphereusinghighpurityelementsof99.8%Ni. 99.7%Mnand99.9%Ga.Afterannealingat850?for

    10h.theingotwasmechanicallycrushedintoparticles withsizelessthan3mm.Theseparticlesmixedwith acetoneweresealedinavia1.Ballmillingwasperformed intheOM1SP4planetaryballmillandtheOM3A

    vibrationballmil1.respectively.Thehardenedsteelballs wereusedandthebal1..to..powdermassratiowasabout 10:1.Aftermillingfor0.5h.1hand4h.respectively, theparticlesweretakenoutfromthevialfollowedby drying.The4hmillingparticleswereannealedat600?

    for1h.Then.thephasetransforlTlationtemperaturesof asmilledandannealedparticlesweremeasuredby PerkinElmerDiamondDSCatacooling/heatingrateOf 20oC/min.Xraydiffraction(XRD)wascarriedoutfor phaseidentificationatroomtemperatureusinga PanalyticalXPertPROdiffractometerwithCuK

    Correspondingauthor:ZHENGYu-feng;Tel:+86-451-82518644;E-mail:yfzhen~hrbeu.e

    ducn

    CHENFeng,etal/Trans.NonferrousMet.Soc.China17(2007)s615 radiation.Themorphologyofallparticleswas

    $240scanningelectron determinedwithCambridge

    microscope(SEM),andtheparticlesizedistributionwas

measuredusingRise2002particlesizeanalyzer.

    3Resultsanddiscussion

    3.1Observationformorphologyofasmilledparticles

    Fig.1showsthesurfacemorphologiesof4h

    asmilledparticlesbyPBMf4hPBMparticles)and

    VBMf4hVBMparticles).observedbySEM.From

    Fig.1(a),theshapeofparticlesispolyhedronwithsize distributionfrom5umto40um.InFig.1(b),itcanbe seenthattheparticlesisinflakyshapemainlywithsize distributionbetween3umand30um.TheenergYOf VBMismuchhigherthanthatofPBM.sotheparticles ballmilledbyVBMshouldbedestroyedmoreseriously incontrasttoPBMprocessduringthesameballmilling time.Therefore,thedifierentparticleshapecanbe obtainedbythesetwoballmillingprocess.

    Fig.1SEMimagesforNi498Mn285Ga217alloyparticles preparedbyPBM(a)andVBM(b)for4h

    3.2Structuraltransitionofparticlesduringball milling

    TheroomtemperatureXRDpa~emsforparticles afterdifferentballmillingtimesusingPBMandVBM areshowninFig.2.ByreferringtoRef.[5],thebulkalloy couldbeindexedas5Mtetragonalmartensite.Afterball millingfor0.5hand1hbvPBM.thediffractionpeaks ofmartensitebecomeweakgraduallysuchas(202),(400) or(004)peaks.Whenupto4h,themartensitepeaks almostdisappearcompletely,andothernewdiffraction peaksappear.Thesenewpeakscanbeindexedasphase withfctstructure.whichhasalsobeenfomadbyWANG

etal[14inNi2MnGaballmilledparticles.InRe~[14],

    thefctstructurephaseisconsideredtobea

    nonmodulatedmartensitewithJ)l(about343K1closeto Currietemperature(about375K).Butaccordingto DSCresultshowninFig.3fa1.theballmilled

    Ni498Mn28.

    5Ga217alloyparticlesdonotundergoa

    martensitictransformationwhenthetemperaturerange extendsfrom-20?to120?.Hereby,thisfctstructure

    phaseshouldnotbeamartensitephase,butadisordered fctstructurephase.Sothestructureevolvesfrom tetragonalstructuretodisorderedfctstructureafter4h PBMprocess.However,thedifierentstructureevolution resultinVBMprocesshasbeenobtainedincontrastto PBMprocess.TheresultcanbeseeninFig.2(b),the martensitepeakshavedisappearedcompletelyinthe particlesballmilledfor0.5howingtotheseverelattice deformation.whichisdifierentfromtheresultof0.5h PBMprocess.Withballmillingtimeincreasingto4h. 20/(.)

    20/(.)

    Fig.2XRDpa~ernsofbulksamplesandballmilled Ni498Mn285Ga2l7particlesbyPBM(a)andVBM(b)for differenttimes

    s616CHENFeng,etal/Trans.NonferrousMet.Soc.China17(20071 someotherdiffractionpeakshavealsobeenfound, whichcanbeindexedasdisorderedfccstructure accordingtotheRef.[14].Sothestructureofparticles evolvesfrom5Mtetragonalstructuretodisorderedfcc

    structureafter4hVBM.Thisstructuraltransitionfrom thelowercrystalsymmetry(tetragonalstructure)tothe highercrystalsymmetry(cubicstructure)shouldbe attributedtotheseverelatticedistortiongeneratedinthe VBMprocess.

    Itisknownthattheparticlesarecrushed

    predominantlyundershearingstressinPBMprocessand undercompressingstressinVBMprocess.Theenergyof VBMisalsolargerthanPBM.SothesetwodifferentbalI millingconditionsmayleadtothetwostructural transitionduringtheballmillingprocess.

    3.3Influenceofannealingonstructureofas-milled particles

    Theeligibleparticlesusedinsmartcomposites shouldhavethesamephysicalpropertiesasthebulk alloy,sothebal1.milledparticlesareannealedat600?

    for1h.TheDSCresultsofbulk.bal1.milledparticles andannealedparticlesareshowninFig.3.Asshownin Fig.3(a),thephasetransformationpeaksof4hPBM

    particlesdisappearincontrasttothebulkmaterials,and thenreappearafterannealingat600?.Bycalculation

    themartensitictransformationlatentheatofannealed particlesisslightlysmallerthanthatofthebulkalloy. Themartensiticandreversetransformationtemperatures arealsoverysimilartothebulkmateria1.TheXRD resultfortheannealedparticlesisshowninFig.4(a),itis evidentthediffractionpeakscanbeindexedtothesame crystalstructurephaseasthebulk.5Mtetragonal martensitephase.Sothephysicalpropertiesof 4h.PBM.particlescanberesumedtothestateofbuIk

materialafterannealingat600?for1h.Therefore.

    theseannealedparticlesaresuitabletobeusedinsmart composites.

    FromFig.3(b),thephasetransformationbehavior cannotbeseenin4hVBM.particles,Moreover,italso doesn'toccurwhentheseparticlesareannealedat600?

    for1h.whichisdifferentfromtheresultintheannealed 4h.PBM.particles.TheXRDpattemforannealed

    VBMparticlesisshowninFig.4(b).Byindexing,the 4h

    cubicaustenitephaseexistspredominantlyinthese particles.Therearetwosmallpeakswhichcannotbe indexedappearinginthetwosidesofaustenite(220) peak.111ehighenergyofVBMhasledtotheverylarge deformationofcrystallatticeforthealloy.During annealingprocess,theatomswillgraduallyadjusttothe configurationofHeuslerstructurebvdiffusion.Butthe atomconfigurationfromdisorderedfcctoHeuslerisnot completeintheprocess,annealingat600?for1h,due

    totheseverelatticedistortion.Sothespaceofsome Temperature/~C

    Temperature/~C

    Fig.3DSCcurvesofbulksamples,4hasmilledandthen

    annealedat600?for1hNi49.

    8Mn285Ga2l7particles

    preparedbyPBM(a)andVBM(b)

    20/(.)

    30405O6O708O9O

    20/(.)

    Fig.4XRDpatternsofannealedNi49.

    8Mn285Ga2i7particlesat

600?for1hpreparedbyPBM(a1andVBM(b1

    一一多旨一\?00{l-,旨一50{

    CHENFeng,etaUTrans.NonferrousMet.Soc.China17(2007) crystalfacesmaybesmallerorlargerthanthatof Heuslerstructureaustenitephase(220)crystalface. Hereby,thesetwocorrespondingsmalldiffractionpeaks canbeseeninthetwosidesofaustenite(220)Deak.The internalstresswillbeinducedowingtothelattice distortionstillexistingintheannealedparticles.which willinfluencethemartensitictransformation.Theresult ofinternalstressinhibitingtheintermartensitic transformationhasbeenreportedbywANGetal[15].So thedisappearanceofmartensitictransformationinthe annealed4hVBMparticlesshouldbeattributedtothe internalstressefrect.Thecompleteatomconfigurationof these4hVBMparticlesfromdisorderedfeetoHeusler structureshouldneedhighertemperatureannealing above600?.orlongerannealingtimethan1hat

    600?.

    Accordingtotheaboveresults.itisfoundthatthe disorderedfctstructureinthe4hPBMparticleswill

    completelyevolvetotheHeuslerstructureafer annealing600?for1h.However,thedisorderedfcc

    structureinthe4hVBMparticlesdon'ttransformtothe Heuslerstructurecompletelyafterannealingat600?

    for1h.Thisresultisduetothehigherseveredistortion forthealloyparticlescausedinVBMthaninPBM process.

    4Conclusions

    1)ThepolygonNi498Mn285Ga21.7alloyparticlesand flakyshapeNi498Mn285Ga2l7alloyparticleshavebeen fabricatedby4hPBMprocessand4hVBMprocess. respectively.

    2,Thestructuraltransitionoftheparticlesfrom5M tetragonaltodisorderedfctstructureandfrom5M tetragonaltodisorderedfccstructurehavebeenfound duringthePBMandVBMprocesses.respectively. 31Aferannealingat600?for1h,boththe

    disorderedfctanddisorderedfeestructureoftheball milledparticlesevolvetotheHeuslerstructure. 4)ThephysicalpropertyofballmilledNiMnGa

    particlesmayretrievetothebulkstateafterappropriate temperatureannealing.Thisindicatesthattheseannealed NiMnGaparticleswouldbesuitabletobeusedinsmart composites.

    References

    s617

    [1MuRRYSJ,MARION1MA,KuKLAAM,ROBINSONJ, O'HANDLEYRC.ALLENSMLargefieldinducedstraininsingle crystallineNi-Mn-Gaferro~nagneticshapememoryalloy[J.JAppl

    Phys,2000,87f91:5774-5776

    [21uLLAKKOK,HUANGJK,KANTNERC,KOKORrNvV O'HANDLEYRCLargemagnetic.field.inducedstrainsin Ni2MnGasinglecrystals]J].ApplPhysLett,1996,69:19661968.

    [3SOzINOVA,LIKHACHEvAA,LANSKAN,uLLAKKOK. Giantmagnetic.field.inducedstraininNiMnGaseven.1ayered martensiticphase[J].ApplPhysLett,2002,80(10):17461748.

    [4MARIONIMA,O'HANDLEYRC,ALLENSM,HALLSR, PAULDI,RICHARDML.FEUCHTWANGERJ.PETERSONB,v.

CHAMBERSJM.TECHAPIESANCHAROENKIJRThe

    ferromagneticshapememoryeffectinNi-Mn-Ga[J].JMagnMagn Mater.2005:290/291:3541.

    f51ANGCB,MUHAMMADDENGLF,WUW,XUHB

    CompositiondependenceonthemartensiticstructuresoftheMn.rich NiMnGaalloys]J].ActaMaterialia,2004.52:2779-2785. [6STRAKAL,HECZKOO,LANSKAN.Magneticpropertiesof variousmartensiticphasesinNi.Mn.Gaalloy[J1IEEETransMagn 2002,38f51:2835-2837.

    [7DONGJw,XIEJQ,LuJ,ADELMANNC,PALMSTR0MCJ,

    CUIJ,PAN0,SHIELDTW,JAMESRD,MCKERNANSShape

    memoryandferromagneticshapememoryeffectsinsingle.crystal Ni2MnGathinfilms]J].JApplPhys,2004,95(5):25932660 81PONSJ,SEGUIC,CHERNENKOVA,CESARIE,OCHINP' PORTIERR.Transformationandageingbehaviourofmelt.spun NiMnGashapememoryalloys]J].MaterSciEngA.1999:273/275: 315319

    f91FEUCHTWANGERJ,MICHAELS,JUANGJ,BONOD,

    O'HANDLEYRC.ALLENSM.JENKISC.GOLDIEJ.

    BERKOWITZAEnergyabsorptioninNi.Mn.Ga.polymer composites]J].JApplPhys,2003,93(10):85288530.

    101SCHEERBAUMN,HINZD,GUTFLEISCHO,MULLERKH, SCHU【』TZLTexturedpolymerbondedcompositeswithNi.Mn.Ga magneticshapememoryparticles[J].ActaMaterialia,2007,55: 2707-2713

    l11SOLOMONVC,MCCARTNEYMR,SMITHDJ,TANGYJ,

    BERKOWITZAE.O'HANDLEYRCMagneticdomain

    configurationsinspark.erodedferromagneticshapememory Ni-Mn-Gaparticles]J].ApplPhysLett,2005,86:192503.

Report this document

For any questions or suggestions please email
cust-service@docsford.com