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简介：LowcarbonsteelswithBandPadditionswereremeltedbyelectromagneticlevitationandsolidifiedinavacuumdroptube.Thedropletvolumesweresettobe2mm×2mm×2mm(TM)and5mm×5mm×5mm(FM),respectively.Themicrostructureofrapidlysolidifiedsteeldroplets(cooledinsiliconoil)withPandbothBandPadditionwasobserved.ThemicrostructuresofB-bearingdropletsamplesweremoreuniformthanthoseofB-freeones,forbothTMandFMsamples.Thedistributionof℃andPalongthediameterofeachsamplewasdetected.Thewell-distributionof℃andPwasdetectedinB-bearingdropletsamples.SoitcouldbededucedthatBwasalsowelldistributedinthesteels.ItwasBatomsthatpromotedthewell-distributionof℃andP,whichfurtherimprovedtheuniformityofmicrostructureundertheconditionofrapidsolidification.Themicro-hardnessofBbearingsampleswashigherthanthatofB-freesamples,andthehardeningmechanismwasdiscussedindetail.

简介：以正硅酸乙酯和葡萄糖分别作Si源和C源，草酸和硼酸分别作催化剂，采用溶胶一凝胶法制备SiC前驱体，并采用碳热还原法制备纳米SiC。采用XRD、SEM对样品的物相和形貌进行表征。结果表明，用草酸作催化剂制备的前驱体在1550℃制备的SiC是颗粒与晶须的混合体，颗粒粒径为30~50nm，晶须长度为1～3μm，晶须直径为60～100nm；用硼酸作催化剂制备的前驱体其碳热还原温度显著降低，在1400℃就能制备出SiC颗粒与晶须的混合体，颗粒粒径为20~30nm，由于B加入后的抑制作用，SiC晶须的含量明显减少。

简介：PositronannihilationbehaviorshavebeenstudiedinthesinglephaseNd2Fe14BmagnetandthenanocompositeNd2Fe14B/α-Femagnet,preparedbymeltspinning.Theresultsshowedthatthenumberofvacancy-clusteratgrainboundariesincreaseswithincreasingannealingtemperatureforthebothtypesofmagnets.Theincreaseofthiskindofdefectcanimprovethecoercivityof

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简介：MoleculardynamicssimulationusingauniversalforcefieldhasbeenemployedtodeterminethediffusioncoefficientsofO2andNa2SO4vaporintoB2O3andSiCfrom700Kto1273K,respectively.Einsteindiffusionwasobservedina250～300pssimulation.ThediffusioncoefficientfortheO2rangefromabout9.279×10-9cm2/sforB2O3to2.275×10-10cm2/sforSiCataloadingof32moleculespersimulationbox,thatfortheNa2SO4vaporrangefromabout9.888×10-7cm2/sforB2O3to1.837×10-10cm2/sforSiCataloadingof8moleculespersimulationbox.EnvironmentpropertiesofC/SiCcompositewillbeincreasedviatheB2O3preventingthediffusionofO2andNa2SO4vaporintothepyrolyticinterphaseandcarbonfibers.

简介：通过对不同环境状态下实验数据的统计分析，研究采用简单线性回归分析方法和组合Weibull分析方法计算材料许用值的准确性。研究结果表明，与采用Weibull分布方法相比，采用简单线性回归方法或组合weibull分析方法估算复合材料的B基准许用值，可有效提高许用值的准确度。

简介：有alloying原子X=C，B，N，O和空缺的镁和它的合金的概括叠的差错(GSF)精力和表面精力用第一原则的方法被调查了。叠的差错精力上的alloying原子和空缺的占优势的减少效果在slip飞机附近在第一层从他们的位置被结果，这被发现。叠的差错精力是将近与纯镁一样当alloying原子和空缺被放在时第二，第三，第4，第5和第6层。O强烈减少Mg的GSF精力，这被显示出。alloying原子C，B和N增加表面精力，但是O和空缺减少Mg的表面精力。Mg和Mg合金的韧性被使用在表面精力和不稳定的叠差错精力之间的比率基于瑞斯标准讨论了。

简介：ExperimentswerecarriedouttostudytheinfluenceofsurfaceconditiononexpulsionduringthespotweldingofAZ31BMgalloy.AgeneralelectricalcontactresistancetheoryforconductiveroughsurfacesandtherelationbetweenmaximumtemperatureTminthecontactandvoltage-dropVacrossinterfaceoftwosurfaceswereemployedtounderstandthereasonofexpulsioninMgalloyspotwelding.Themainreasonofexpulsionisthatthehighelectricalcontactresistanceinducedbylargeroughnessofthesurfaceandoxidefilmcoveredonthesurfaceleadstolocalmeltingofmetalintheinterfaceoftwosurfaces,andliquidmetalofthelocalareaejectedfromthespecimenunderelectrodeforceformsexpulsion.

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简介：ItwasshownbyTEMandX-rayanalysisthatNi3AlisthemainphaseoftheintermetallicsynthesizedundercompressionfromthepowdermixtureofNiwithAlalloyedbyB.TheNi3Bisasecondaryphase.ThevalueofthelatticeparameteroftheintermetallicNi3AlwithandwithoutBincreaseswhentheconcentrationofAlincreases.TheincreaseinAlconcentrationfrom23.5to25.0intheinitialpowdermixtureleadstodecreasingthesolubilityofBintheNi3Alphase.

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简介：为stoichiometric作文的nanocrystallineNd-Fe-B磁铁的demangetization曲线被使用微磁力的有限元素技术计算。曲线，特别iHc随N.The很小的iHc的增加变得更小从一系列沿着不同的地方向的曲线为N=∞接近那。iHc随L的增加增加，并且是什么的靠近的cr一些比小试验性的价值应该是。

简介：采用液态压铸技术，研究了压铸工艺参数对AM60B合金显微组织的影响。试验结果表明，当浇注温度为680℃、模具温度为180℃、压射速度为3．0m／s、压射比压为75MPa时，压铸镁合金AM60B可以获得组织均匀细小、表面光滑、缺陷极少的铸件。

简介：综述了当前B4C增强Al基复合材料的研究现状,通过对比不同制备工艺所得复合材料的拉伸强度、硬度、耐磨性能和延伸率等力学性能,总结了粉末冶金法、高能球磨法、无压渗透法、搅拌铸造法以及其他制备技术的优缺点,提出复合材料制备过程中存在的问题及解决方法;此外还介绍了B4C的强化机制;并对B4C增强Al基复合材料未来发展方向和研究重点进行了展望。

简介：近日，Nanocyl公司与3B-玻璃纤维公司达成合作协议，共同开发一款新型碳纳米管玻璃纤维产品，该产品将大大迎合飞速增长的热塑性塑料和结构复合材料的市场发展趋势。据协议规定，3B-玻璃纤维公司将提供玻璃纤维，而Nanocyl公司的多功能碳纳米管上浆剂可以有效增强复合材料的机械和导电性能。

简介：Inthisstudy,Almatrixcompositesreinforcedby7.5and15vol.%B4CparticlesandalsomonolithicAl（AlwithouttheB4Cparticles）wereproducedbywetattritionmillingandsubsequenthotforwardextrusionprocesses.Themicrostructureofthecomposites,evaluatedbyscanningelectronmicroscopy（SEM）,showedthattheB4CparticleswereproperlydistributedintheAlmatrix.MechanicalpropertiesoftheAI/B4CcompositesandmonolithicAlwereinvestigatedbytensile,wearandhardnesstests.TheresultsrevealedthatwithincreasingcontentofB4Cparticles,thetensilestrengthandmicrohardnessofcompositesincreasedbuttheelongationdecreased.Inaddition,thetensilestrengthandmicrohardnessofcompositesampleswerehigherthanthoseofmonolithicAl.ThedensitymeasurementsrevealedthatthedensityofcompositesdecreasedwithincreasingcontentoftheB4Cparticles.

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简介：1.IntroductionSofarthemicrostructureandcoercivityofSm（Co,Cu,Fe,Zr）7.4alloyhavebeenstudiedindetailbyvariousauthors.TheeffectofZr-richlaminarphasestructureonthehighcoecivityofalloyismoreattractive.Thechangesofmagnetic