简介：Themechanicalpropertiesofwoodpowder/polypropy!enecompositeswithdifferentwoodparticlesizesandwoodspecieshavebeenstudied.AllofthewoodparticiesizesincreasedtheE-modulusofthecomposites.Tensiletestsshowedthatwoodpartidesizeshadanegativeeffectontheelongationatbreakandthetensilestrengthofthecompositeshasbeenimprovedwhenwoodparticlesizeswerebe(ow150μm(below100mesh).Fortheimpacttests,thewoodpartidesizeshadanegativeeffect,buttheMDFf...

简介：Inthispaper,thedispersionandnucleationbehaviorofultrafineparticlesofsilicaandlayeredsilicate(LS)inpoly(ethyleneterephthalate)(PET)matrixareinvestigatedandcharacterizedbyTransmissionElectronMicroscopy(TEM),WideAngleX-rayDiffraction(WAXD),DynamicScanningCalorimetry(DSC),andAtomicForceMicroscopy(AFM).ThesolidprecursorsbasedonsilicaandLSaresuggestedoriginallyforpreparingnanocompositeswithgooddispersionmorphology.Resultsshowthattheinitialsub-micron(1000～500nm)LSparticlesareexfoliatedordispersedintonanometer-scaleparticles(30～70nm)duringtheirpolymerizationwithPETmonomers.Thesedispersednanoparticlesformanorderedmorphologyintheirnucleationandgrowthduringannealingnanocomposites.DSCpatternsrevealthatthedoublemeltingpeaksofannealedPET-LSnanocompositesdisappear,whiletheyhaveshrunkeninPET-silicaones.ThesefindingsstronglydemonstratethatthedispersednanoparticlesacceleratethecrystallizationofPET.ThedispersedLSparticleshavehigherpercolationandnucleationperformancethanthoseofsilica.Thehomogeneousdistributionmorphologyofultrafineparticlesiseasilyobtainedbycontrollingtheloadoftheircorrespondingprecursors.SuchadispersionobviouslyimprovesPETpropertiesinthatitsheatdistortiontemperature(HDT)increasesfrom76℃to103℃,andcrystallizationincreases2～4timesmorethanthatofPET.Especially,thenanocompositefilmskeepthemselvestransparentwhenparticleloadiswithin2wt.%thoughthereare3wt.%orsoofagglomeratedparticlesinthenanocomposites.

简介：Theaimofthepaperistodiscoverthegeneralcreepmechanismsfortheshortfiberreinforcementmatrixcomposites(MMCs)underuniaxialstressstatesandtobuildarelationshipbetweenthemacroscopicsteadycreepbehaviorandthematerialmicrogeometricparameters.Theunitcellmodelswereusedtocalculatethemacroscopiccreepbehaviorwithdifferentmicrogeometricparametersoffibersondifferentloadingdirections.Theinfluenceofthegeometricparametersofthefibersandloadingdirectionsonthemacroscopiccreepbehaviorhadbeenobtained,anddescribedquantitatively.Thematrix/fiberinterfacehadbeenconsideredbyathirdlayer,matrix/fiberinterlayer,intheunitcellswithdifferentcreeppropertiesandthickness.Basedonthenumericalresultsoftheunitcellmodels,astatisticmodelhadbeenpresentedfortheplanerandomly-distributed-fiberMMCs.Thefiberbreakagehadbeentakenintoaccountinthestatisticmodelforitstartsexperimentallyearlyinthecreeplife.Withthedistributionofthegeometricparametersofthefibers,theresultsofthestatisticmodelagreewellwiththeexperiments.Withthestatisticmodel,theinfluenceofthegeometricparametersandthebreakageofthefibersaswellasthepropertiesandthicknessoftheinterlayeronthemacroscopicsteadycreepratehavebeendiscussed.

简介：AnewmethodforcorrosionprotectionofAl-basedmetalmatrixcomposites(MMC)wasdevelopedusingtwo-stepprocess,whichinvolvesanodizinginH2SO4solutionandsealinginrareearthsolution.Corrosionresistanceofthetreatedsurfacewasevaluatedwithpolarizationcurves.TheresultsshowedthattheeffectoftheprotectionusingrareearthsealingisequivalenttothatusingchromatesealingforAl6061/SiCp.TherareearthmetalsaltcanbeanalternativetothetoxicchromateforsealinganodizedAlMMC.

简介：为angle-interlockwoven的有弹性的行为分析的一个微机械模型陶器的composites在这篇论文被建议。这个模型由在空间，在邻近的纱之间的洞和纱的实际剖面图几何学认为纤维是波动和连续性考虑实际织物结构。基于laminate理论，编织的3D角度联锁的有弹性的性质陶器的composites被预言。交叉的纬的不同数字几乎有一样的有弹性的moduli。陶器的矩阵的厚度在有弹性的moduli上有小效果。当波动比率增加纵的模量减少和另外的幼仔的moduli增加时。在理论预言和试验性的结果之间的好同意在分析编织的3Dangle-interlock的有弹性的性质表明建议模型的可行性陶器的composites。这篇论文的结果验证分析聚酯矩阵composites的方法对编织陶器的composites合适的事实。

简介：Weldabilityofpolyetheretherketone(PEEK)withpolyetherimide(PEI)istested.AndcarbonfiberreinforcedPEEKlaminatesareresistanceweldedusingstainlesssteelmeshheatingelement.Theeffectsoftheweldingtimeandweldingpressureonthelapshearstrengthofjointsareinvestigated.ResultsshowthatPEEKcanhealwithPEIwellinweldingconditionandthelapshearstrengthofPEEK/CF(carbonfibre)jointincreaseslinearlywithweldingtime,butreachesamaximumvaluewhenweldingpressurerangingfrom0.3MPato0.5MPawithconstantweldingtime.ThefracturecharacteristicsofsurfaceareanalyzedbySEMtechniques,andfourtypesoffracturemodesoflapshearjointsaresuggested.

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简介：ThecreepbehaviorofAI2O3.SiO2fiberreinforcedZL109compositeshasbeeninvestigatedatfourtemperaturesrangingfrom553to623K.Theresultsshowhighstressexponentandhighapparentcreepactivationenergy.Agoodcorrelationbetweenthenormalizedcreeprateandnormalizedeffectivestressmeansthatthetruestressexponentofminimumcreepstrainrateofthecompositeisverycloseto5,andtheminimumcreepstrainrateismatrixlatticediffusioncontrolled.Thethresholdstressdecreaseswithincreasingtemperaturelinearlyanddisappearsatatemperaturecloseto623K.Itisassumedthatthelongrangeinternalbackstressesgeneratedincreepreducetheloadtransfertofibersandtheinteractionbetweendislocationsandstrengtheningprecipitatesdecreasesathightemperature.Atahightemperaturewherethelongrangeinternalbackstressesisveryclosetotheappliedstress,thethresholdstressdisappears.

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简介：Inthepresentstudy,amodifiedHall-Petchcorrelationonthebasisofdislocationpile-upmodelwasusedtoestimatetheyieldstrengthofSiCp/Alcomposites.TheexperimentalresultsshowthatthemodifiedHall-Petchcorrelationexpressedasσcy=244+371λ-1/2fitsverywellwiththeexperimentaldata,whichindicatedthatthestrengthincreaseofSiCp/Alcompositesmightbeduetothedirectblockingofdislocationmotionbytheparticulate-matrixinterface,namely,thedislocationpile-upisthemostpossiblestrengtheningmechanismforSiCp/Alcomposites.

简介：ThisworkstudiedthecharacteristicsofSiO2distributionandstructureofsilicatephasesinMgO-ZrO2compositessynthesizedbyrawmaterialsoflightfiredmagnesitendzircon,Theresultsindicatethat30wt%-40wt%SiO2contentinthesystemisexistedintheformofcrystallineofforsterite(M2S),theremainderingofSiOcontent(60wt%0-70wt%)isexistedintheglassphase,Thechemicalcompositionofglassphaseiswellagreedwiththechemicalcompositionofmonticellite(CMS).

简介：Thekineticprocessofslagcorrosionforβ－Sialonandβ-Sialon-Al2O3compositeshasbeenstudiedbymeansofdipmethod(staticandself-rotating),Thecorrosionmodelisbuitlandtheformulaofcorrosionrateisdeduced,whichareinaccordancewithexperimentalresults.

简介：Theboundaryelementmethodwasimprovedforthe2Delasticcompositeswithrandomlydistributedinclusions.Thisproblemcanbereducedtoaboundaryintegralequationforamulti-connecteddomain.Further,consideringthematricesofthetractionsanddisplacementsforeachgroupoftheidenticalinclusionwerethesame,aneffectivecomputationalschemewasdesigned,sincetheordersoftheresultingmatrixequationscanbegreatlyreduced.Numericalexamplesindicatethatthisboundaryelementmethodschemeismoreeffectivethantheconventionalmulti-domainboundaryelementmethodforsuchaproblem.Thepresentschemecanbeusedtoinvestigatetheeffectivemechanicalpropertiesofthefiber-reinforcedcomposites.

简介：ThepiezoelectriccompositescontaininghighlyorientedBaTiO3whiskersasactivephaseandPVDFasmatrixhavebeenpreparedbymicro-holeextrusionandorientationincarriedfibers.ThemorphologyoforientedBaTiO3whiskersandmicrostructureofthecompositeswereobservedbySEM.Asforitselectromechanicalproperties,itisfoundthatthedielectricconstant,piezoelectricconstantandremnantofpolarizationintheBaTiO3whisker-PVDFcompositeareconsiderablyhigherthanthatintheBaTiO3powders-PVDFcomposite,whilethelossfactorsfollowtheoppositetrend.FortheBaTiO3whisker-PVDFcomposite,thevaluesofε,d33andPrparalleltothewhiskerorientation(normalspecimen)aremuchhigherthanthatperpendiculartothewhiskerorientation(parallelspecimen).Thesignificanteffectsoftheconnectivepassagesofactivephaseonelectromechanicalpropertiesofthepiezoelectriccompositeshasalsobeeninvestigated.

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简介：Inthispaper,thebehavioroftwocollinearcracksinmagneto-electro-elasticcompositematerialunderanti-planeshearstressloadingisstudiedbytheSchmidtmethodforpermeableelectricboundaryconditions.ByusingtheFouriertransform,theproblemcanbesolvedwithasetoftripleintegralequationsinwhichtheunknownvariableisthejumpofdisplacementsacrossthecracksurfaces.Insolvingthetripleintegralequations,theunknownvariableisexpandedinaseriesofJacobipolynomials.Numericalsolutionsareobtained.Itisshownthatthestressfieldisindependentoftheelectricfieldandthemagneticflux.

简介：TheZrO2-Al2O3ceramiccompositeswerepreparedbyappropriatetechniqueswithcommercialZrO2andAl2O3powdersasrawmaterialsandY2O3asstabilizer.TheresultsindicatethatwiththeintroductionofAl2O3intotheZrO2matrixwherethequantityofadditiveY2O3is3.5%(molefraction),thegrowthofZrO2grainsisefficientlyinhibited,whichhelpstheZrO2grainsexistinametastabletetragonalmanner;thushigherstrengthandtoughnessareacquired.Whenthecontentofaluminais20%(massfraction),thebendingstrengthandfracturetoughnessofthecompositesare676.7MPaand10MPa·m1/2respectively,themechanicalbehaviorsareclosetothosepreparedwithZrO2andAl2O3powderssynthesizedthroughwetchemicalapproach.Themechanicalbehaviorsofthecompositesarewellimprovedowingtothedispersiontougheningofaluminagrainsandphasetransformationtougheningofzirconiagrains.

简介：(1-x)La_(0.67)Ca_(0.33)MnO_3/Cr_2O_3(LCMO)+xCr_2O_3composites被一个新液相方法综合。XRD和SEM大小表明在LCMO结构和LCMO的晶格常数可溶的很少Cr_2O_3几乎没变化，当大多数Cr_2O_3在谷物边界或在LCMO谷物的表面上是分布式的时。Inresistivity对温度大小，金属--绝缘体转变被观察什么时候x<0.20。抵抗力增加和金属--绝缘体转变温度与Cr_2O_3的增加的内容减少。一个随机的电阻器网络(KRN)模型被使用，到模仿混合样品的运输性质。模拟结果同意试验性的观察。结果证明方法为理解maganite的composites的电子运输是合理的。

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简介：TheinteractionbetweenZn-AleutecticalloyandAl2O3p/6061Alcompositesinthevacuumfurnacewasinvestigated.Greatattentionhasbeenpaidtotheelementsdiffusion,themicrostructureandformationoftheinterfacebetweenZn-AIeutecticalloyandAl2O3p/6061Alcomposites.ExperimentalresultsshowthatZn-AleutecticalloyhasagoodwettingabilitytoAl2O3p/6061Alcompositesandthewettingangledecreaseswithincreasingthetemperatureinvacuum.Aftertheinteraction,aninteractionlayerformsbetweenZn-AIalloyandAl2O3p/6061Alcomposites.Thephasesintheinteractionlayermainlyconsistofα-Al(Zn),Al2O3andCuZn5resultedfromthediffusionofelementsfromtheZn-Alalloy.SeveralporositiesdistributeintheregionneartheinterfaceoftheZn-Alalloy/interactionlayer.TheamountofshrinkagevoidsintheinteractinglayerisrelevanttothepenetrationofZnelementintoAl2O3p/6061Alcompositeswhichisafunctionoftemperature.SoitisnecessarytolowerheatingtemperatureinordertolimittheZnpenetration.