简介：AdditionofAl-5Ti-1Balloytomoltenaluminumalloyscanrefineα-Algrainseffectivelyandtherebyimprovetheirstrengthandtoughness.TiAl3andTiB2inAl-5Ti-1Balloyarethemainsecondary-phaseparticlesforrefinement,whiletheunderstandingontheeffectoftheirsizesonα-Algrainrefinementcontinuestobefragmented.Therefore,Al-5Ti-1Balloyswithvarioussizesandmorphologiesofthesecondary-phaseparticleswerepreparedbyequalchannelangularpressing(ECAP).Evolutionofthesecondary-phaseparticlesduringECAPprocessandtheirimpactonα-AlgrainrefinementwerestudiedbyX-raydiffractionandscanningelectronmicroscope(SEM).ResultsshowthatduringtheECAPprocess,micro-cracksfirstlyappearedinsideTiAl3particlesandthengraduallyexpanded,whichresultedincontinuousrefinementofTiAl3particles.Inaddition,micro-distributionuniformityofTiB2particleswasimprovedduetotheimpingementofTiAl3particlestoTiB2clustersduringdeformation.ExcessivelylargesizesofTiAl3particleswouldreducethenumberofeffectiveheterogeneousnucleusandthusresultedinpoorgrainrefinementeffectiveness.Moreover,excessivelysmallTiAl3particleswouldreduceinhibitoryfactorsforgraingrowthQandweakengrainrefinementeffectiveness.Therefore,anoptimalsizerangeof18-22μmforTiAl3particleswassuggested.

简介：Thecreepmechanismofas-castMg-6Al-6Ndalloywasstudied.Thestressexponentforcreepis5.8undertheappliedstressesof50-70MPaat175°C.Theactivationenergyforcreepis189kJ·mol-1undertheappliedstressof70MPaintherangeof150-200°C.Thetruestressexponentandthresholdstressforcreeparecalculatedas4.96and10.2MPa,respectively.Thetruestressexponentindicatesthatitscreepmechanismbelongstothedislocationclimb-controlledcreep,whichisinagreementwiththemicrostructurechangesbeforeandaftercreep.ThehighvalueforstressexponentisattributedtotheinteractionofAl11Nd3phasewithdislocations.Theactivationenergyismorethantheself-diffusionactivationenergyofMg,whichisattributedtotheloadtransfertakingplacefromthematrixtoAl11Nd3phaseduringcreep.

简介：

简介：Theelectronbeamwelding-brazingbeingusedtojoin5A06AlalloytoTC4Tialloydecreasestheformationofbrittleintermetalliccompound.Experimentswerecarriedouttostudytheinfluenceofelectronbeamweldingparametersonthetensilestrengthofwelds,basedonanorthogonaltestandanalysismethod.Theweldingparametersincludebeamcurrent,weldingspeed,scanningfigure,scanningfrequency,figuresize,beamoffsetandfocuscurrent.Theoptimumparametersfor3mm5A06Alalloyand2mmTC4alloywereasfollows:accelerationvoltagewas60kV,beamcurrentwas11mA,weldingspeedwas600mm/min,focuscurrentwas0mA,scanfigurewasO,scanningfrequencywas1000Hzandbeamoffsetwas0.5mm.Theresultsshowthatthejointswerewithgoodappearanceandqualityweldedbytheoptimumparameters.ThesuccessfuljointscouldbegainedandthemaximumtensilestrengthofAl/Tidissimilaralloyjointscouldbeupto222.61MPausingelectronbeamwelding-brazing.

简介：采用电子束和真空白耗电弧熔炼法制备Nb-Ti-Al（质量分数，％）合金，利用料浆熔烧法在合金表面制备Si—Cr-Ti涂层，研究在1400℃下合金与涂层的氧化行为。通过X射线衍射（XRD）、扫描电镜（SEM）、能谱分析（EDS）及电子探针微区分析（EPMA）研究基体与涂层氧化前后的组织形貌变化及成分分布。结果表明：Nb．40Ti-7A1合金在1400℃氧化1～11h后，氧化产物均主要为TiNb2O7、TiO2、Al2O3；氧化前，涂层丰要由（Nb，Ti，Cr，A1）Si2主体层与（Ti，Nb，Al）5Si3过渡层组成，高温氧化后涂层表面形成含有A1203、Ti02的Si02阻挡层；合金与涂层的氧化行为均遵循抛物线规律，合金在1400℃氧化11h的单何面积质量增量为161．98mg／cm2，而涂覆涂层后单位面积质量增量降至9．56mg／cm2，表明Si-Cr-Ti涂层具备良好的高温抗氧化性能。

简介：微观结构和Al-Cu-Mg-Ag合金的机械性质上的Ce和Ti增加的效果被学习了。Ce或Ti能减少，这被显示出Al-Cu-Mg-Ag合金的当演员组谷物尺寸，为Ω的成核比率作为异构的成核中心分阶段执行，在老化期间禁止Ω阶段的生长，并且因此增加Ω的间距分阶段执行的体积部分和减少的增加。这些微观结构增加收益力量和张力的力量。然而，如果Ce和Ti被加到合金，他们形成(Ce，Ti)包含的混合物和增加谷物在扔期间缩放，但是没在老化期间在成核和Ω阶段的生长上有效果。包含Ce和Ti的合金与包含Ce或Ti的合金相比有相对更低的Vicks坚硬和力量。

简介：

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.

简介：采用一种新型高通量实验方法,实现对Ti-5553合金（Ti-5Al-5Mo-5V-3Cr,质量分数,%）在600～700℃范围内的连续温度梯度热处理。实验通过对圆台形样品进行直流电加热,由于截面面积不同而导致电流热效应不同,从而使样品表面温度呈梯度变化。采用端淬实验实现Ti-5553合金的连续冷却速率变化,研究合金在不同热处理条件下的显微组织演变和力学性能。结果表明：Ti-5553合金的伪调幅分解温度为（617±1）℃,析出的α相尺寸在300nm左右;合金在伪调幅分解温度下时效4h达到最高的硬度。因此,这种高通量方法能够快速准确地判断合金中相转变温度以及相应的组织转变。

简介：

简介：摘要本文利用高真空多功能电弧熔炼设备制备出Ti-Al-V三元合金钮扣锭，并对其进行了金相、扫描电镜组织分析和研究。

简介：TheeffectsofheattreatmentsonthephasetransformationbehaviorofTi49Ni49.5Fe1V0.5andTi48Ni48.5Fe1V2.5alloyswereinvestigated.TheresultsindicatethatthealloyssubjectedtodifferentheattreatmentshaveB2structureatroomtemperature.AllthespecimensexhibitatwostageB2→R→B190martensitictransformationoncooling,butaB190→B2one-stagereversemartensitictransformationonheatingexceptagedA1alloy,whichundergoesanabnormaltwo-stagetransformationuponheating.ThephasetransformationtemperaturesareaffectedbyheattreatmentsandVcontent,whichcanbeattributedtothevariationofthesecond-phaseparticlescontentinthematrix.

简介：Er^3+-dopedSrBi4Ti4O15-Bi4Ti3O12(SBT-BIT-xEr^3+,x=0.00,0.05,0.10,0.15and0.20)inter-growthceramicsweresynthesizedbythesolid-statereactionmethod.Structural,electricalandup-conversionpropertiesofSBT-BIT-xEr^3+wereinvestigated.Allsamplesshowedasinglephaseoftheorthorhombicstructure.RamanspectroscopyindicatedthattheEr^3+substitutionforBi^3+atAsitesofthepseudo-perovskitelayerincreasesthelatticedistortionofSBT-BIT-xEr^3+ceramics.ThesubstitutionofBi^3+byEr^3+leadstoadecreaseofdielectriclosstanδandanincreaseofconductivityactivationenergy.Piezoelectricconstantd33wasslightlyimproved,butdielectricconstantwasdecreasedwiththeEr^3+doping.TheSBT-BIT-xEr^3+ceramicwithx=0.15exhibitstheoptimizedelectricalbehavior(d33~17pC/N,tanδ~0.83%).Moreover,twobrightgreen(532and548nm)andonered(670nm)emissionbandswereobservedunderthe980nmexcitation.Optimizedemissionintensitywasalsoobtainedwhenx=0.15fortheSBT-BIT-xEr^3+ceramic.Therefore,thiskindofceramicsoughttobepromisingcandidatesformultifunctionaloptoelectronicapplications.

简介：本文利用群论的知识,从CH4的分子结构出发,研究了群C4v的特征及其特征表的性质,所得结论与用化学方法是相同的.

简介：美国旧金山的金门大桥跨越1900多米的金门海峡，连接起北加利福尼亚与旧金山半岛，大桥建成通车后，大大节省了两地往来的时间。但是新问题随之出现，由于出行车辆很多，金门大桥总会堵车。

简介：Inthispaper,X-raydiffractogramanalysisandSEMobservationofAl4C3formedathightemperaturefromcarbon-containingrefractorieswithAlhavebeencarriedout.Aluminumaddedtocarbon-containingrefractoriesreactswithC(s)toformAl4C3(s)graduallyduringheatingfrom600℃to1200℃.ItisconsideredthattheinterlockedstructureofAl4C3platecrystalspromotestheoutstandingincreaseofhotmodulusofruptureofcarbon-containingrefractorieswithAl.TheHMORofcarbon-containingrefractoriesaddedwithAladditivefrom0to5wt％increasesby2.8timesbeingfrom6.5MPato18.2MPa.AfterathermochemicalcalculationforhydrationreactionprocessesofAl4C3andH2O(g),theequilibriumpartialpressurechartofH2O(g)inH2O-Al4C3-Al(OH)3systemvsvarioustemperatureshasbeenattained.TheH2O(g)partialpressureintheairneededfortheAl4C3hydrationreactionisnomorethan10～18atmatthetemperaturebelow120℃.Itisconsideredthattheburnedcarbon-containingrefractorieswithAlisextremelyeasytohydrateandthecrackingofburnedcarbon-containingrefractoriesisgeneratedbecausethatthehydrationexpansionis2.11timesduringtransformingfromAl4C3toAl(OH)3.ThefundamentalmeasureagainsthydrationoftherefractoriesistoinsulatetherefractoriesfromH2O(g)byvariousmeanssuchaspitchimpregnationorothersealingmaterials.

简介：Inthisstudy,C_f/AlcompositesandTiAlalloyswerejoinedbyanewmethodnamedlaser-ignitedselfpropagatingsynthesis(SHS).Mixedpowdersof63.0Ni-31.9Al-5.1Ti(wt%)wereusedasjoininginterlayer.Perfectjointwasgot.ThemicrostructureevolutionandformationmechanismoftheSHSjointwereinvestigatedbyscanningelectronmicroscopy(SEM),energy-dispersivespectroscopy(EDS)andX-raydiffraction(XRD).Resultsshowthatlocalizedmeltingoccursonbothsides.Oneγ-Ni_(0.35)Al_(0.30)Ti_(0.35)andtwoNi-Alreactionlayersform,respectively,intheTiAl/interlayerandC_f/Al/interlayerinterfaces.ThecombustionofNi-Al-TiinterlayerbeginswiththesharpreactionofNiandAl.TheinterlayerproductisaeutecticorganizationofNiAlandAl-richγ.

简介：为研究固态Ti/Al扩散偶的扩散反应,将Ti/Al箔构成的扩散偶分别在525,550,575和600°C退火1～40h。实验结果表明TiAl3是Ti/Al界面处生成的唯一相。TiAl3的优先长大是界面热力学作用的结果。TiAl3相主要向Al箔一侧长大,其长大过程符合抛物线规律。在晶界扩散的基础上,用有限差分方法模拟TiAl3相的长大过程,模拟结果和实验结果吻合较好。

简介：摘要：铝合金作为当今社会中常见的金属材料之一被广泛的应用在交通、建筑、航空航天、航海、电力、医疗、装饰等各个领域。将晶粒细化剂参入铝合金熔炼，使得铝熔体在凝固过程中获得足够的异质晶核，从而细化金属晶粒的尺寸来提升铝材性能已经成为如今工业生产中最为普遍且经济实用的方法。

简介：ＭｏｓｓｂａｕｅｒＥｆｆｅｃｔｏｆＲａｐｉｄｌｙＱｕｅｎｃｈｅｄＡｌ－Ｆｅ－Ｖ－Ｓｉ－ＭｍＡｌｌｏｙｓＷａｎｇＪｉａｎｑｉａｎｇ（王建强），ＣｈａｏＹｕｅｓｈｅｎｇ（晁月盛），ＺｅｎｇＭｅｉｇｕａｎｇ（曾梅光），ＺｈａｎｇＢａｏｊｉｎ（张宝金），Ｃｈ...