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简介：Asystematicalsimulationhasbeencarriedoutontheindentationcreeptestonparticle-reinforcedcomposites.Thedeformation,failuremechanismsandlifeareanalyzedbythreereasonablemodels.Thefollowingfivefactorshavebeenconsideredsimultaneously:creeppropertyoftheparticle,creeppropertyofthematrix,theshapeoftheparticle,thevolumefractionoftheparticleandthesize(relativesizetotheparticle)oftheindentationindenter.Forallthecases,thepowerlawrespectingtotheappliedstresscanbeusedtomodelthesteadyindentationcreepdepthrateoftheindenter,andthedetailexpressionshavebeenpresented.Thecomputersimulationprecisionisanalyzedbythetwo-phasemodelandthethree-phasemodel.Twoplacesofthestressconcentrationarefoundinthecomposites.Oneisaheadoftheindentationindenter,wherethehighstressstateisdeducedbytheedgeoftheindenterandwilldecreaserapidlyneartoasteadyvaluewiththecreeptime.Theotheroneisattheinterface,wherethehighstressstateisdeducedbythemisfitofmaterialpropertiesbetweentheparticlesandmatrix.Ithasbeenfoundthatthecreepdissipationenergydensityotherthanastressparametercanbeusedtobethecriteriontomodelthedebondingoftheinterfaces.Withthecriterionofthecriticalcreepdissipationenergydensity,apowerlawtotheappliedstresswithnegativeexponentcanbeusedtomodelthefailurelifededucedbythedebondingofinterfaces.Theinfluencesoftheshapeoftheparticlesandthematchingofcreeppropertiesofparticleandmatrixcanbediscussedforthefailure.Withacrackmodel,thefurthergrowthofinterfacecrackisanalyzed,andsomeimportantexperimentalphenomenacanbepredicted.Thefailuremechanismwhichtheparticlewillbepunchedintomatrixhasbeenalsodiscussed.Thecriticaldiflerencesbetweenthecreeppropertiesoftheparticlesandmatrixhavebeencalculated,afteraparameterhasbeendefined.Intheviewofcompetitionoffailure

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简介：PhysicalsimulationisusedtostudythemovementofnonmetallicparticlesinAlmeltinelectromagneticfield.ItisfoundthattheterminalvelocityofparticlesindifferentReynoldsnumberrangehasdifferentfunctions.ByconfirmingdragforcecoefficientofnonmetallicparticleswithReynoldsnumberintherangeof0.2～10and10～25respectively,twofunctionsofterminalvelocityforsphericalnonmetallicparticleshavebeengotaccordingly,whichprovideatheoreticalbasisforseparatingnonmetallicinclusionsfromAlmeltinelectromagneticfield.

简介：Microstructureofthematrixdirectlyinfluencestheperformanceandtheapplicationofmetalmatrixcomposites.Byusingvacuumcasting-infiltrationmethodtomanufacturecastingtungstencarbideparticlereinforcedcomposite,theadditionofNicanalterthemicrostructureofthematrixofcomposite.Highcarbonchromiumsteelwaschosenasthesubstrate.Thecastingprocesswasachievedat1580℃withvacuumdegreeof0.072—0.078MPa.Paddingofthemoltensteelineachpartofthepreformwasdifferent,andthesolidificationofeachpartofthecompositewasdifferent,too.Microstructureofthematrixwasvariousindifferentpartsofthecomposite.TheNiadditionhadenlargedtheaustenitezoneinmatrix,whichwouldimprovethecorrosionresistanceofthecomposite.ThephaseidentificationofthecompositewasperformedbyX-raydiffractiontechnique.TheresultshowedthatFe3W3Cwastheprimaryprecipitatedcarbideanditscompositionhadadirectlinkwiththedecompositionofthecastingtungstencarbideparticles.Thehardnessofthematrixmainlydependedonthereinforcedcarbide,i.e.Fe3W3C.

简介：粒子特征上的火焰温度和SiCl4集中的效果被学习。火焰温度分布用修改的钠线颠倒技术被测量。粒子被石英支持收集并且被沿着火焰中心线在不同地点扫描电子显微镜(SEM)分析。当SiCl4集中是16g/min时，粒子首先种然后与火焰缩小温度增加。当SiCl4集中是26g/min时，火焰温度几乎没沿着火焰和许多大球形的粒子在粒子特征上有小影响一路上存在。

简介：TransportationofoxygenfromAI203shelltotheencapsulatedAIcoreundertheelectronbeamirradiationwasachievedbyfieldemissionguntransmissionelectronmicroscope.

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简介：Highentropyalloyhasattractedincreasingattentions.However,toenhancethealloystrengthoftenleadstoimpairmentoftheductility,orviceversa.HerewereportedaheattreatmentapproachonAlCrFeNi2Ti0.5highentropyalloy,whichcanelevatethestrengthandductilitysimultaneously.AningotofAlCrFeNi2Ti0.5weighing2.5kgwasfirstlyfabricatedbymediumfrequencyinductionmelting.Thensamplesfromthesameheightofthebulkingotwereannealedfor6hat600,700,800and1000℃,respectively.After1000℃annealing,anoptimalmicrostructurewasobtainedbyusingourapproachwhichcanmakesomeprecipitationparticlesdistributehomogeneouslyinthedendriteinteriorwhilekeeptheinterdendritestructureasasinglesolidsolutionphase.ThemechanicaltestonthisAlCrFeNi2Ti0.5alloysampleshowedthat,thecompressivefracturestrengthσbcwasincreasedbyabout600MPaandtheplasticstrainepwasdoubled,comparedwiththoseoftheas-castsample.Ourapproachcanbereadilyadaptedtolarge-scaleindustrialproductionofhighentropyalloyswithhighstrengthandductilitybyproperannealingtreatment.