学科分类
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158 个结果
  • 简介:Theboundaryelementmethodwasimprovedforthe2Delasticcompositeswithrandomlydistributedinclusions.Thisproblemcanbereducedtoaboundaryintegralequationforamulti-connecteddomain.Further,consideringthematricesofthetractionsanddisplacementsforeachgroupoftheidenticalinclusionwerethesame,aneffectivecomputationalschemewasdesigned,sincetheordersoftheresultingmatrixequationscanbegreatlyreduced.Numericalexamplesindicatethatthisboundaryelementmethodschemeismoreeffectivethantheconventionalmulti-domainboundaryelementmethodforsuchaproblem.Thepresentschemecanbeusedtoinvestigatetheeffectivemechanicalpropertiesofthefiber-reinforcedcomposites.

  • 标签: 包含 数字模拟 边界元素 2D弹性 光学纤维
  • 简介:Coppercoatingwasdepositedonthesurfaceofaluminumboratewhiskerbyanelectrolessplatingmethod.Thismethodwasusedtomodifytheinterfacialpropertyofsqueeze-castingaluminumboratewhiskerreinforced6061Almatrixcomposite.Interfaceobservationindicatesthatthespinelreaction(MgAl2O4)ishinderedbythecoppercoating,andthedifferenceininterfacialreactiondegreeaffectsthetensilepropertyandagingbehaviorofthecomposite.Forthecompositewithlessspinelreaction(MgAl2O4),itspeak-agingprocessarepostponedduetolessdepletionofmagnesium.Onthefracturesurfaceofcopper-coatedcompositedimplesandfracturesofwhiskersaremore,butonthefracturesurfaceofuncoatedcompositepull-outofwhiskersaremorethanthatonthecoatedone.Inuncoatedcompositethefracturegenerallyoriginatesfromthenear-interface-region.

  • 标签: ALUMINUM BORATE WHISKER ALUMINUM matrix composite
  • 简介:HotcompressionbehaviorofTiC–Al2O3/AlcompositeswasstudiedusingtheGleeble-1500systematatemperaturerangeof300–550°Candatstrainraterangeof0.01–10.00s-1.TheassociatedstructuralchangeswerestudiedbyTEMobservations.Theresultsshowthatstressleveldecreaseswithdeformationtemperatureincreasingandstrainratedecreasing,whichcanberepresentedbyaZener–Hollomonparameterinanexponent-typeequationwithhotdeformationactivationenergyQof172.56kJ·mol-1.Dynamicrecoveryoccurseasilywhenstrainratesarelessthan10.00s-1.Dynamicrecrystallizationcanoccuratstrainrateof10.00s-1.

  • 标签: TiC–Al2O3/Al COMPOSITES HOT DEFORMATION Flow stres
  • 简介:ThepiezoelectriccompositescontaininghighlyorientedBaTiO3whiskersasactivephaseandPVDFasmatrixhavebeenpreparedbymicro-holeextrusionandorientationincarriedfibers.ThemorphologyoforientedBaTiO3whiskersandmicrostructureofthecompositeswereobservedbySEM.Asforitselectromechanicalproperties,itisfoundthatthedielectricconstant,piezoelectricconstantandremnantofpolarizationintheBaTiO3whisker-PVDFcompositeareconsiderablyhigherthanthatintheBaTiO3powders-PVDFcomposite,whilethelossfactorsfollowtheoppositetrend.FortheBaTiO3whisker-PVDFcomposite,thevaluesofε,d33andPrparalleltothewhiskerorientation(normalspecimen)aremuchhigherthanthatperpendiculartothewhiskerorientation(parallelspecimen).Thesignificanteffectsoftheconnectivepassagesofactivephaseonelectromechanicalpropertiesofthepiezoelectriccompositeshasalsobeeninvestigated.

  • 标签: 压电化合物 BaTiO3晶须 电化学性质 极化 连接通道 微孔挤压
  • 简介:Toobtainthecompatiblematerialofhighhardnessandhightoughness,Hadfieldsteelmatrixcomposites,reinforcedbyhigh-Crcastironbarsmadeofflux-coredweldingwires,whichwereinsertedintotheHadfieldsteelmelt,wereinvestigated.Themechanicalpropertiesofthreematerials,ie,compositesforas-castandquenching-watercondition,aswellasHadfieldsteel,werecompared.Theresultsshowthatthealloypowderinsideflux-coredweldingwirescanbemeltedbytheheatcapacityofHadfieldsteelmeltandsolidifyintohigh-Crcastironbars.Theimpacttoughnessofthecompositeforquenching-waterconditionishigherthanthatofthecompositeforas-castconditionandislowerthanthatoftheHadfieldsteel,butitcanstillmeettherequirementsofhardnessandtoughnessinindustrialapplication.Regardlessofloadvariation,compositeforquenching-waterconditionshowsbetterwearresistancethanthoseofthecompositeforas-castconditionandHadfieldsteel.ThemodifiedfracturetoughnessandwearresistanceofcompositesareattributedtonotonlythecombiningactionsofHadfieldsteelmatrixandhigh-Crcastironbars,butalsotheeffectofheattreatment.

  • 标签: 钢基复合材料 高铬铸铁 力学性能 微观结构 药芯焊丝
  • 简介:陶器的LaNiO3样品被稳固的州的反应方法在不同sintering温度准备。这被发现结果不是ABO3perovskite单身者阶段,但是双阶段La2NiO4和NiO,和二个阶段的百分比与sintering温度变化了。在1400湩的陶艺sintered??

  • 标签: 烧结温度 电弧侵蚀 侵蚀特性 陶瓷样品 复合材料 镍酸镧
  • 简介:在这个工作,flame-retardant聚丙烯(PP)/ramie纤维(RF)合成被准备。苎麻纤维被生产经由的包含磷、包含氮的火焰retardant(FR)化学上包在situ冷凝作用反应以便压制他们的烛蕊效果。红外线的光谱学(FTIR),X光检查光电子光谱学(XPS)和扫描电子显微镜学(SEM)表明了的Fourier变换苎麻纤维由FR(FR-RF)化学上包了,这成功地被获得。Thermogravimatric测试证明PP/FR-RF合成比PP/RF在高温度有更多的残余和更好热的稳定性合成。锥热量计(CC)结果显示热版本率(PHRR)和全部的热版本(THR)的山峰相应地与整洁的PP/RF的价值相比在23.4%和12.5%减少了。PP/FR-RF合成在燃烧以后创造了连续、紧缩的字符层。在有热传导系数的CC测试以后的字符残余的联合FTIR分析结果,RF上的FR的charring极大地削弱了RF的烛蕊效果,这能被结束,并且在RF域的更多的字符残余在整个燃烧地区便于更多的连续、紧缩的字符层的形成,因而在燃烧期间保护了PPcomposites,导致比PP/RF的合成的PP/FR-RF的更好的火焰retardancy合成。

  • 标签: 纤维复合材料 阻燃聚丙烯 苎麻纤维 包裹 烛芯 傅里叶变换红外光谱
  • 简介:有bimodal粒子尺寸的钻石/铜composites的热传导性被学习。composites与40和100颗m尺寸钻石的混合物通过液体铜的压力渗入被准备进钻石预先形成。有钻石的不同coarse-to-fine体积比率的预先形成的渗透被调查。有bimodal尺寸分发的钻石/铜composites的热传导性与从Chu开发的一个分析模型导出的理论价值相比。钻石/铜composites能到达更高热的传导性,他们的表面粗糙能被使用bimodal钻石粒子尺寸改进,这被预言。

  • 标签: 铜复合材料 颗粒尺寸分布 金刚石 双峰 压力 渗透法
  • 简介:Inthisstudy,Almatrixcompositesreinforcedby7.5and15vol.%B4CparticlesandalsomonolithicAl(AlwithouttheB4Cparticles)wereproducedbywetattritionmillingandsubsequenthotforwardextrusionprocesses.Themicrostructureofthecomposites,evaluatedbyscanningelectronmicroscopy(SEM),showedthattheB4CparticleswereproperlydistributedintheAlmatrix.MechanicalpropertiesoftheAI/B4CcompositesandmonolithicAlwereinvestigatedbytensile,wearandhardnesstests.TheresultsrevealedthatwithincreasingcontentofB4Cparticles,thetensilestrengthandmicrohardnessofcompositesincreasedbuttheelongationdecreased.Inaddition,thetensilestrengthandmicrohardnessofcompositesampleswerehigherthanthoseofmonolithicAl.ThedensitymeasurementsrevealedthatthedensityofcompositesdecreasedwithincreasingcontentoftheB4Cparticles.

  • 标签: 铝基复合材料 湿法研磨 微观结构 力学性能 热挤压 B4C
  • 简介:Duetotheminiaturizationofmoderndevicesre-quirecomponentswithlightweight,highintegra-tionandtheabilitytostoreenergyinassmallvol-umeaspossible.Asaresult,energystoragedensitybecomesanimportantfigureofmeritforenergystor-agedevices.Inthispaper,firstly,wediscussedtheenergydensityinfine-grainedleadzirconatetita-nateglass-ceramicscompositewiththehelpofthe

  • 标签: 英语 阅读 理解 复合材料
  • 简介:Anovelin-situroutewasemployedtosynthesizeLiFePO4/carbon-nanofibers(CNFs)composites.Theroutecombinedhigh-temperaturesolidphasereactionwithchemicalvapordeposition(CVD)usingFe2O3andLiH2PO4astheprecursorsforLiFePO4growthandacetylene(C2H2)asthecarbonsourceforCNFsgrowth.ThecompositeswerecharacterizedbyX-raydiffraction(XRD),Brunauer-Emmett-Teller(BET)specificsurfacearea,fieldemissionscanningelectronmicroscopy(FE-SEM),andtransmissionelectronmicroscopy(TEM).Theelectrochemicalperformanceofthecompositeswasstudiedbygalvanostaticcyclingandcyclicvoltammetry(CV).Theresultsshowedthatthein-situCNFsgrowthcouldberealizedbythecatalyticeffectoftheFe2O3precursor.Thesampleafter80minCVDreactionshowedthebestelectrochemicalperformance,indicatingapromisingapplicationinhigh-powerLi-ionbatteries.

  • 标签:
  • 简介:ZrN-basedcompositesweresynthesizedfromzirconiaviaaluminothermicreductionandnitridationproceswithAlpowdersandMgOasthereductantandsinteringaids,respectively.ZrN-basedcompositesarepromisingforapplicationintherefractorymaterialsorotherhightemperatureindustryfields.TheeffectsofextraAlpowderonphysicalproperties,phasetransformationandmicrostructureswereinvestigated.ProductswithdifferenphasecompositionandmorphologieswereobtainedwithdifferentAlpowdersadditions.TheproductswerecomposedofZrN,ZrO_2,MgAl_2O_4,andZrAl_3O_3Nbyaluminothermalreductionandnitridationofzirconiawith0%extraAlpowdersaddition.ThediffractionpeaksoZrNwerethestrongestwhilepeaksofZrO_2vanishedwith6%extraAladdition.ThethermodynamiccalculationindicatedthatintroducingMgOintothesystemcouldpromotethereactionprocess.

  • 标签: 铝热还原 复合材料 物理性能 氮化法 锆基 制备