简介：Becauseoftheexcellentmechanicalpropertiesof34C「NiMo6steel,itiswidelyusedinhigh-valuecomponents.Manyconventionalapproachestostrengthening-steelstypicallyinvolvethelossofusefulductility.Inthisstudy,34CrNiMo6Steelhavinghighstrengthandductilityisproducedbylasersolidforming(LSF)w让haquenching-tempering(QT)treatment.TemperingofbainiteismainlybysolidphasetransformationinthepreviousLSFlayersduringtheLSFprocess.ThestablemicrostructureofLSFconsistsofferriteandfinecarbides.Themicrostructuretransferstotemperedsorbiteafterheat-treatment.ThetensilepropertiesoftheLSFsteelmeetthoseofthewroughtstandard.TheUTSandelongationofLSFsampleat858MPa,19.2%,respectively,aregreaterthanthoseofthewrought.TheQTtreatmentenhancedtheultimatetensilestrengthandyieldstrengthoftheLSFsample.Theultimatetensilestrength,yieldstrength,reductioninarea,andelongationoftheLSF+QTsampleat980MPa,916MPa,58.9%,and13.9%,respectively,aregreaterthanthoseofthewroughtstandard.TheyieldstrengthoftheLSF+QTsampleisapproximately1.27timesthatofthewrought.TheLSFsamplesfailedinaductilefracturemode,whiletheLSF+QTsamplesshowedmixed-modefailure.ThedefectshaveonlyasmalleffectonthetensilepropertiesowingtotheexcellentductilityoftheLSFsample.

简介：AdditivelymanufacturedTi-6Al-4Vlatticestructureshavefoundimportantnicheapplications.However,theyoftenshowinsufficientcompressiveductilityorinsufficientstructuralintegrity.Inthisstudy,abatchof45octahedralTi-6Al-4Vlatticestructureswasmanufacturedinthreedifferentstrutdiameters(0.5,1.0,1.5mm)byselectiveelectronbeammelting(SEBM).Theinfluenceofpost-SEBMannealingonthecompressivedeformationcharacteristicsofthelatticestructurewasinvestigated.Theas-builtTi-6AI-4Vlatticesfragmentedwhenthecompressivestrainreached13%-23%dependingonstrutdiameter.Annealingat950℃(Ptransustemperature:995℃)onlyslightlyimprovedthecompressiveductilityofthelatticestructures.However,annealingat1050℃(p-annealing)fundamentallychangedthecompressivedeformationmodeofthelatticestructures.Theresultantcompressivestress-straincurvewasfeaturedbyalongsmoothplateauandnofactureoccurredevenaftersignificantdensificationofthelatticestructurehadtakenplace(>50%ofcompressivestrain).

简介：Anovel,Ti-6A1-4V(Ti64)/Hydroxyapatite(HAat5%byweightconcentration)metal/ceramiccompositehasbeenfabricatedusingelectronbeampowderbedfusion(EPBF)additivemanufacturing(AM):specifically,thecommercialelectronbeammelting(EBMR)process.InadditiontosolidTi64andTi64/5%HAsamples,fourdifferentunitcell(model)open-cellularmeshstructuresfortheTi64/5%HAcompositewerefabricatedhavingdensitiesrangingfrom0.68to1.12g/cm^3,andcorrespondingYoung'smodulirangingfrom2.9to8.0GPa,andcompressivestrengthsrangingfrom-3to11MPa.ThesolidTi64/5%HAcompositeexhibitedanoptimaltensilestrengthof123MPa,andelongationof5.5%incontrasttoamaximumcompressivestrengthof875MPa.Boththesolidcompositeandmeshsamplesdeformedprimarilybybrittledeformation,withthemeshsamplesexhibitingerratic,brittlecrushing.Solid,EPBF-fabricatedTi64sampleshadaVickersmicroindentationhardnessof4.1GPawhiletheTi64/5%HAsolidcompositeexhibitedaVickersmicroindentationhardnessof6.8GPa.ThelowestdensityTi64/5%HAcompositemeshstrutsectionshadaVickersmicroindentationhardnessof7.1GPa.Opticalmetallography(OM)andseanningelectronmicroscopy(SEM)analysisshowedtheHAdispersoidstobehighlysegregatedalongdomainorgrainboundaries,buthomogeneouslydistributedalongalpha(hcp)plateletboundarieswithinthesedomainsintheTi64matrixforboththesolidandmeshcomposites.Thealphaplateletwidthvariedfrom-5μmintheEPBF-fabricatedTi64to-1.1μmfortheTi64/5%HAmeshstrut.TheprecursorHApowderdiameteraveraged5μm,incontrasttothedispersedHAparticlediametersintheTi64/5%HAcompositewhichaveraged0.5μm.ThisworkhighlightstheuseofEPBFAMasanovelprocessforfabricationofatruecompositestructure,consistingofaTi64matrixandinterspersedandexposedHAdomains,whichtotheauthorsknowledgehasnotbeenreportedbefore.Theresultsalsoillustratetheprospectsnotonlyforfabrica

简介：Three-dimensional-printed(3D-P)titaniumimplantsdisplaymanyadvantages,suchasdesignflexibility,higherefficiency,thecapabilitytoeasilyconstructcomplexorcustomizedstructures,etc.,andisbelievedtopotentiallyreplacetraditionalimplants.However,thebiologicalperformanceofthe3D-Ptitaniumsurfacehasnotbeeninvestigatedsystematically.Herein,weanalyzedthesurfacecharacteristicsof3D-PTi6AI4Vimplantsandevaluatedthebiologicalresponsesofbonemarrowderivedmesenchymalstromalcells(BMSCs)tothe3D-Psurfaceinvitro.Moreover,afterimplantationintotheratfemoralcondylefor3and6weeks,theosseointegrationperformaneewasevaluated.Theresultsshowedthe3D-PTi6Al4Vimplantpresenteddistinctfluctuantmacroscaleroughsurfaceandrelativelybetterhydrophilicitywhichenhancedtheadhesion,proliferation,osteogenicdifferentiationandangiogeneticfactorexpressionofBMSCs.Moreover,theinvivoosseointegrationperformancewasalsobetterthanthatofthecontrolgroupattheearlystage.Thepresentstudysuggestedthe3D-Ptitaniumalloyisapromisingcandidatetobeusedasimplantmaterial.