文档介绍：该【Columnar to equiaxed transition during β heat treatment in a near β alloy by laser additive manufacture 2021 Min Qi 】是由【贾敬】上传分享，文档一共【10】页，该文档可以免费在线阅读，需要了解更多关于【Columnar to equiaxed transition during β heat treatment in a near β alloy by laser additive manufacture 2021 Min Qi 】的内容，可以使用淘豆网的站内搜索功能，选择自己适合的文档，以下文字是截取该文章内的部分文字，如需要获得完整电子版，请下载此文档到您的设备，方便您编辑和打印。journalofmaterialsresearchandtechnology2021;13:1159e1168
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OriginalArticle
Columnartoequiaxedtransitionduringbheat
treatmentinanearballoybylaseradditive
manufacture
*
MinQia,b,1,SensenHuangb,c,1,YingjieMaa,b,c,,,b,
**
RuixueZhangd,JiankeQiua,b,c,JiafengLeia,b,c,,RuiYanga,b,c
aSchoolofMaterialsScienceandEngineering,UniversityofScienceandTechnologyofChina,Shenyang,110016,
China
bShi-changxuInnovationCenterforAdvancedMaterials,InstituteofMetalResearch,ChineseAcademyofSciences,
Shenyang,110016,China
cInnovationGroupofMarineEngineeringMaterialsandCorrosionControl,SouthernMarineScienceandEngineering
GuangdongLaboratory,Zhuhai,519080,China
dSchoolofMaterialsScienceandEngineering,NortheasternUniversity,Shenyang,110819,China
articleinfoabstract
Articlehistory:ColumnarbgrainsarewidelypresentintitaniumalloysfabricatedbyAdditive
Received11March2021Manufacturing(AM),
Accepted21May2021outstandingchallengeistofacilitatethecolumnartoequiaxedtransition(CET)oftheprior
,CETandtheunderlyinggraingrowthmechanismduringbheat
treatmentinTie5Ale5Moe5Ve1Cre1Fe(Ti55511)alloymanufacturedbyselectedlaser
Keywords:melting(SLM)andlasermetaldeposition(LMD),the
Titaniumalloyquasi-in-situobservationwasemployedintheAMnearbtitaniumalloysbytheelectron
Selectivelasermeltingbackscatterdiffractiontechniquetoanalyzemorphology,crystalorientationandsub-
Lasermetaldepositionstructureevolution,especiallyinthesituationofbamboo-likemicrostructurewith
Postheat-
Recrystallizationbgrainsenrichedlow-anglegrainboundaries(LAGB)areinahighstoredstrainenergystate
Graingrowthinas-depositedSLMTi55511leadingtoarecrystallizednucleation-and-growthprocess
duringheattreatment,whilethepriorbgrainscontainingasmallamountorevennoLAGB
areinarelativelylowerstoredstrainenergystateinas-depositedLMDTi55511resultingin
recrystallizationandgraingrowthprocesses.
©2021TheAuthor(s).
BY-NC-NDlicense(-nc-nd//).
*Correspondingauthor.
**Correspondingauthor.
E-mailaddresses:******@(),jfl******@().
1Theseauthorscontributedequallytothiswork.
/
2238-7854/©2021TheAuthor(s).-NC-NDlicense(http://
-nc-nd//).
1160journalofmaterialsresearchandtechnology2021;13:1159e1168
Moreover,Ithasbeenreportedbythework[28]thattheCET
storedstrainenergy,whichisassociatedwiththedislocation
,thedislocationdensityofthebphasein
fieldsduetotheiradvantagesofhighspecificstrengthandcorro-AMalloyfabricatedbydifferentprintingmethodsissupposed
eeeee
sionresistance[1,2].Amongwhich,Ti5Al5Mo5V1Cr1Fe,astobedifferentduetothedifferenceinheatinputandcooling
b
ahighstrengthneartitaniumalloy,,untilnow,fewresearchworksaredonecon-
structuralcomponents,.,,thequasi-in-situobservationof
gearbeams[3].However,forthereasonofhighmaterialscostandCETduringbheattreatmentwascarriedoutinbothlaser
long-termfabricatingprocesses,further,applicationsoftitaniummetaldeposition(LMD)andselectivelasermelting(SLM)
alloysarerestricted[4].
AdditiveManufacturing(AM)or3Dprintinghasdevelopedphenomenonwasfoundinbothalloys,whiletherelatedb
rapidlyinthelastfewdecades[5].Comparedwithconven-graingrowthbehaviorandunderlyinggraingrowthmecha-
tionalmanufacturingtechnologies,-
characteristics,suchasnear-netshapingandfabricatingmoteadeepunderstandingofthegraingrowthmechanismof
e
smallandcomplexstructuralcomponents[68].However,,itprovidesessentialguidance
thedevelopmentofAMalsosuffersplentyofchallenges,inforoptimizingthemicrostructureanddiminishingthe
whichtheevidentanisotropyofmechanicalpropertiesofAManisotropyofmechanicalpropertiesbyanalternateHT-
-
b
alloys,grainswillgrowalongthetemperaturegradientingtimeduringthebheattreatmentinthepracticalprocess.
oppositetothebuildingdirection(BD),resultinginlarge
columnargrainswithalmostconstantorientation[9e12].The
columnarmorphologyleadstoasignificantanisotropyinthe
alongwithdifferentdirections[11].Moreover,thetextureofb
eeeee
grainsalsoinfluencestheatexture,becausetheprecipitationThematerialusedinthisstudywasTi5Al5Mo5V1Cr1Fe
ofaphasefollowstheBurgersorientationrelationshipwith(Ti55511)-deposited
,howtoimprovethedepositionTi55511specimenbySLMwasproducedusingalaserpowerof
mm
microstructuresoftitaniumalloysandobtainsmall-size200W,
equiaxedgrainsarethebottlenecktechniquethatneedstoprocessingparametersfortheLMDincludelaserpowerof3kW,
bo
-transustemperature(Tb,C)ofdeposited
±
bgraintoequiaxedgrainstransition(CET)toreducetheTi55511alloywas8905C,determinedbythemetallographic
(HT)processes,namedHT
[13e19].,.
þ
.,Mo,Cu,B,whichcancausegreatcompositionalunder-TheprocessofHT1wasannealedat950C(Tb60C)for15min
coolingandgraingrowthrestriction,fineandequiaxedbfollowedbywaterquenching(WQ),whileHT2andHT3were
grainsareformedduringthe3Dprintingprocess[20e23].,allspecimens
Traditionalthermaldeformationcanalsopromotethefor-weresealedintheevacuatedquartzcapsulestoremovethein-
.
deforming,thelongcolumnargrainboundariescanbebroken
andtherecrystallizationandgrowthofnewbgrainsoccur
[24,25].Recently,bheattreatmentisadoptedtorealizethe
boundariesandthengrowtobeequiaxedgrains[26].
ThemicrostructureevolutionofAMtitaniumalloysduring
heattreatmenthasbeeninvestigatedinCP-Ti[27]andaþb
titaniumalloys[28],inwhichreconstructedbgrainwas
appliedtoanalyzethebrecrystallizationandgraingrowth
behaviorsincethetransformationofb/aduringthecooling
,onlythemorphologyandcrystalorien-
tationofthereconstructedbphasecouldbeanalyzed,while
thesubstructureactingaspotentnucleationsitesfortheb
bstabilizingelementsleadtothebphaseremainedintheas-
depositedmicrostructureaftereachthermalcycle,which
enabledthedirectobservingofthemoredetailedinformation
ofbphaseviatheelectronbackscatterdiffraction(EBSD)
technique,
Therefore,.
journalofmaterialsresearchandtechnology2021;13:1159e11681161
Anopticalmicroscope(OM)wasfirstperformedtoshowwithwidthrangingfrom100to500mmispresentedinLMD
themicrostructuresinas--
terizingthegrainorientation,substructureevolutionaswelldiameterofabout100mm.
astextureevolution,theEBSDtechniquewasemployedon
-
followingstandardmetallographicprocedures(grinding,pol-treatment
ishingandetchinginasolutionof3%HF,3%HNO3and94%
b
H2O),whilethespecimensforEBSDobservationwereelec-
tropolishedwithasolutionof90%perchloricacidand10%HT1,
alcoholusingavoltageof30Vfor60satÀ25-depositedSLMTi55511(),thenewbgrainswith
quasi-in-situobservation,themagnificationandstepsizeofdiversecrystalorientationsgraduallycapturepriorcolumnar
thefieldwerekeptconstant:
alloy,50Xand12mmforLMDTi55511alloy,,
Moreover,twofiguresweregenerallystitchedtogetherasonebutitdecreaseswiththedurationofelongatingheattreatment.
singleimageonthepowerfulmethodtorevealthemicro-Duetothelimitedmagnification,theshapeofnewgrainsis
,alowermagnificationwithmoregrains
-Channel5systemwascolumnargrainsthatremaininthenewgrainsafterHT3,as
,toobtainaccuratein-solutiontimeasthenewlargegrainsconsumesmallresidual
formationwithminimumremovalofthespecimensurface,grainsthatcanreduceinterfacialenergyofthesystem.
,,,themicrostructureand
crystalorientationshowlittlechangeafterHT1inLMD
Ti55511alloy,whichshowsthedelayofthenewgraingrowth
,
newequiaxedbgrainswithalargersizeprefertogrowfrom
-depositedmicrostructurethezoneofpriorequiaxedgrains,thengraduallyinvadeprior
columnarorequiaxedgrainsinLMDTi55511alloyafterHT2
-,thegrainsizeandcrystalorien-
Ti55511alloysfabricatedbySLMandLMD,-
-,thenewbgrainsareequiaxedcrystals.
structureofSLMTi55511isdominatedbyhighlyanisotropicSimilarly,thenewgraingrowthratedecreaseswithelon-
columnargrains,whiletwotypesofgrains,.,columnargatingheattreatment,andpartialpriorgrainsretaininthe
grainsandequiaxedgrains,aredistributedlayerbylayerinfinalmicrostructureduetoinsufficientholdingtime.
LMDTi55511alloyshowingabamboo-
distributedinthezoneofcolumnargrainsinLMDTi55511
alloy,(PF)ofas-depositedSLM
,
grainsofbothSLMandLMDTi55511alloysarearrangedas-depositedSLMTi55511specimenshowsastrong(100)
approximatelyparalleltotheBDbecauseofunidirectionaltexturedevelopingalongtheBDwithamaximumtexturein-
,themaximumtexture
Ti55511variesfrom20to200mm,
-depositedTi55511specimenfabricatedby:(a)SLM,(b)LMD.
1162journalofmaterialsresearchandtechnology2021;13:1159e1168
-depositedTi55511specimenfabricatedby:(a)SLM,(b)LMD.
:(a)HT1,(b)HT2and(c).
:(a)HT1