简介:AnewcompoundK6Ti0.67Nb15.33O42waspreparedforthefirsttimebysolidstatereactioninK2O-Ni2O3-Nb2O5ternarysystem.Thenewcompoundwascharacterizedbyelectronprobe,X-raypowderdiffractionandDTA.TheresultofX-raypowderdiffractionshowsthatK6Ti0.67Nb15.33O42crystallizesthehexagonalsystemwithunitcellparametersa=9.1341(5)A,c=12.090(1)A.andspacegroupP62/mcm(193).
简介:Usingdirectfinitedifferencemethod,anumericalmodelforsimulatingthetemperaturefieldinthechargeduringinductionskullmelting(ISM)hasbeendeveloped.Onthebasisofthemodel,thetemperaturefieldinTi-47Ni-9Nbingothasbeencalculatedundervariousmeltingconditions.Finally,theprocessingparameters(meltingpower,melting-downtimeandthefinalmelttemperature)havebeenoptimized.
简介:ThemechanismoftheinterfacialreactionofAl2O3/mediumMnsteelcontainingNbwasstudiedbymeansoftheobservationontheinterfacialreactionphenomenonofAl2O3/mediumMnsteel,andtheanalysesontheinterracialphases.TheresultsshowthatwhenT≥1550℃,theinterfacialreac-tionofAl2O3/mediumMnsteelcontainingNbhappened.InthemediumMnsteelmatrix,NbexistsintheformofNbC.NbCarethenucleatingbaseofCOgasbubbles.
简介:在团结微观结构的谷物结构和precipitates极端纯有不同Ti或Nbmicro-alloying的17wt%Cr以铁酸盐为主要成的不锈钢试验性地并且理论上被调查。到钢的Ti或Nb的增加减少了谷物尺寸(D)和延伸因素(E),这被谷物结构观察发现,并且改进了equiaxed谷物比例(P)和球状因素()。在学习的四钢之中,最小的谷物尺寸和最大的equiaxed谷物比例被联合把Ti和Nb加到钢获得。SEM观察显示了那几种猛冲例如锡,MC(在Nb的富人),等等,洗阶段(Fe2Nb)在相应的钢形成了。另外,用Thermo计算软件计算的结果说明了那听在合适的Ti和N内容在液体猛抛。同时,团结间隔(T)被Ti或Nb的增加扩大,并且Nb的有效性比Ti强壮。基于试验性并且计算结果,在equiaxed谷物比例的谷物精炼和增长的机制被讨论。
简介:从卷过程到退火的质地进化440MPa等级忍受Nb高力量的过程如果钢(IF-HSS)被学习。而且,在在退火以后的钢表的厚度方向的不同的节的质地被调查。宏质地大小使用XRD证明在忍受NbIF-HSS的那块热滚动质地包括主要质地部件是的弱纤维和-fiber,{001}110,{111}110并且{111}112。它值得纤维骨骼线在热滚动以后形成了的笔记。在冷滚动期间,绝对最大值变到{111}112沿着沿着纤维的纤维和最大值变到{112}110。在退火的再结晶期间,过程,更弱的纤维和卷质地的更强壮的纤维寒冷转变了质地到退火的很强壮的纤维。当在1/4节的质地紧张比表面和中央部分的高时,在退火以后,到沿着厚度的中央部分的从表面的主要部件为纤维和-fiber,显示一样的字符。
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简介:为了在钨铜成立新电介质陶艺,组织,有名字的公式Ba4PrFe0.5Nb9.5O30被稳固的州的反应方法准备。微观结构和绝缘的性质用粉末X光检查衍射,领域排放扫描电子显微镜,和可变温度电介质被学习测试系统。结果证明陶艺有一个单个阶段并且与=b=的房间属于P4bm的空间组12.4839(3)?,c=3.9409(5)?,V=614.192(2)?3。频率依赖者电介质性质证明陶艺在房间温度有象Debye一样松驰,当温度依赖者电介质性质显示陶艺是relaxor,松驰由于nanopolars和氧空缺时。陶艺作为温度马厩在电子陶艺有潜在的应用多层的陶器的电容器。
简介:Inthiswork,hotisostaticpressing(HIPing)techniquewasusedtodensifytheTi_2AlNbpre-alloyedpowder.TheinfluenceofHIPingloadingrouteparameters(temperatureandratesofheatingandpressurizing)onmicrostructureandpropertiesofPMTi_2AlNballoyswasstudied.TheresultsshowedthatHIPingloadingrouteparametersaffectedthedensificationprocessandmechanicalproperties(especiallyhightemperaturerupturelifetime)ofPMTi_2AlNballoysinthepresentwork.Afiniteelementmethod(FEM)modelforpredictingthefinaldensificationwasdevelopedandwasusedtooptimizetheHIPingprocedure.
简介:Atomized,pre-alloyedTi—24Nb—4Zr—7.9Sn(wt%)powderwasusedtofabricatesolid,prototypecomponentsbyelectronbeammelting(EBM).Vickersmicroindentationhardnessvalueswereobservedtoaverage2GPafortheprecursorpowderand2.5GPaforthesolid,EBM-fabricatedproducts.Thepowderandsolidproductmicrostructureswereexaminedbyopticalandelectronmicroscopy.X-raydiffractionanalysesshowedthattheyhadbccβ-phasemicrostructure.However,itwasfoundbytransmissionelectronmicroscopythattheEBM-fabricatedproducthadplatemorphologywithspace~100—200nm.Althoughthecorrespondingselectedareadiffractionpatternscanbeindexedbyβ-phaseplusα'-martensitewithorthorhombiccrystalstructure,thedark-fieldanalysesfailedtoobservethea'-martensite.Suchphenomenonwasalsofoundindeformedgummetalsandexplainedbystress-induceddiffusionscatteringduetophononsoftening.
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简介:利用XRD、SEM等分析手段,对含微量Zr、Ti的Cr35Ni45Nb合金的力学性能和微观组织相互关系进行了研究。结果表明,该合金组织为奥氏体基体和枝晶间骨架状碳化物,碳化物类型为富铬的M23C6和含铌等强碳化物元素组成的MC;微量Zr、Ti可细化二次析出的Cr35Ni45Nb合金中的碳化物,使其呈粒状较均匀地分布在晶内,从而提高合金的力学性能。
简介:Ag-TiAlintermetallicalloy,Tie45Ale2Nbe2Mn(at.%)e0.8vol.%TiB2,hasbeenprocessedfromgasatomizedprealloyedpowderbyfieldassistedhotpressing(FAHP).Aninitialanalysisoftheprealloyedpowderhelpedontheunderstandingoftheintermetallicsinteringbehavior.Atomizedpowderconsistedofametastablephasethattransformedintoa2tgequilibriumphasesbythermaltreating.Differentpowderparticlemicrostructureswerefound,whichinfluencethemicrostructuredevelopmentoftheFAHPg-TiAlmaterialdependingonthesinteringtemperature.Duplex,nearlylamellarandfullylamellarmicrostructureswereobtainedatthesinteringtemperaturesabove1000C.Lowerconsolidationtemperatures,below1000C,ledtotheformationofanAlrichphaseatpowderparticleboundaries,whichisdeleterioustothemechanicalproperties.Highcompressiveyieldstrengthof1050MPawasobservedinsampleswithFAHPduplexmicrostructuresatroomtemperature.Whereasnearlylamellarandfullylamellarmicrostructuresshowedyieldstrengthvaluesof655and626MPaatroomtemperatureand440and425MPaat750C,respectively,whicharesuperiorincomparisontosimilaralloysprocessedbyothertechniques.Theseexcellentpropertiescanbeexplainedduetothedifferentvolumefractionsofthea2andgphasesandtherefinementofthePMmicrostructures.