简介:TheultrafineWC—Cocompositepowderwassynthesizedbyanewlydevelopedrapidroutebasedoninsitureactions.Byusingtheas-synthesizedcompositepowder,thegranulationprocessingwasthencarriedouttopreparetheultrafine-structuredthermalsprayingfeedstock.Theinfluencesoftheheat-treatmentprocessondensityofthefeedstockpowder,phaseconstitutionandwearresistanceoftheresultantWC—Cocoatingsfabricatedbyhighvelocityoxy-fuel(HVOF)wereinvestigated.Theresultsshowedthatincreasingtheheatingtemperatureandextendingtheholdingtimeleadedtoremarkableincreaseinthedensityandflowabilityofthefeedstockpowder.Asaresult,thedecarburizationofthein-flightparticlescouldbedecreasedandthewearresistanceofcoatingwassignificantlyenhanced.Thepresentstudydemonstratedthatthedevelopedtechniquesfortheultrafinepowderanditsthermal-sprayedcoatingshadverypromisingapplicationsinscalinguptoproduceultrafine-structuredcermetcoatingswithexcellentperformance.
简介:ThesecondaryhardeningreactionisaccompaniedwithprecipitationoffinecarbidesinhighCoNiultrahighstrengthsteel.Thecrystalstructureoftheprecipitatingcarbidesisunambiguouslydeterminedbymicrobeamdiffractionintransmissionelectronmicroscopy.Itisidentifiedthattheneedle-shapedcarbidesareM2Cwithahexagonalstructure.TheconcentrationofsubstitutionalalloyingelementsinthecarbidesquantifiedbyenergydispersiveX-rayspectroscopy(EDS)alsosupportstheresultabove.ThespatialstructureofM2CisidenticalwithL'3type.Metalatomsareinaclosepackedhexagonalstructure,thecarbonatomspartlydistributewithrandomintheoctahedralintersticesandthefillingprobabilityislessthan1/2.Particularattentionwaspaidtotherelationshipofneedle-shapedcarbides/ferritematrixatsecondaryhardeningpeaktemperedat482℃for5h.Observationbyhighresolutiontransmissionelectronmicroscopy(HRTEM)confirmsthatcarbideswithblack-whitecontrastarefullycoherentwithferriteandhaveindividualcrystalstructure,andthecoarsenedcarbideswithmoirefringearepartiallycoherentwithmatrix.TheorientationrelationshipbetweenM2CandferritematrixisdirectlyobservedandidentifiedwiththewellestablishedP-Srelationship[001]α//[111]c.
简介:这些电影的容易的磁化轴与底层平行,这被发现,并且同样劈啪作响、退火的multilayers的磁性在电影飞机是各向同性的。强制的地H//c是4.8kA/m,remanence-to-saturation磁化M//r/M//s的比率是大约0.73为作为--劈啪作响的样品。H//c和M//r/M//s增加温度,增加退火,特别当退火的温度比400度C高时。这些试验性的结果能被使用联合的铁磁性的交换和coercivity的卡住的理论解释。(编辑作者摘要)13个裁判员。
简介:Fromtheprocessofsedimentationthemathematicalrelationshipsamongdepositionvolumeandpowderpropertiesaswellassedimentationparameterswerededuced.Basedontheformulaamathematicalmodelwassetupandsimulatedthroughthecomputer.AtlastthevalidityofmathematicalmodelwassupportedbytherepresentativeexperimentonTi-MosystemFGMpreparedbyco-sedimentation.
简介:TheeffectofLaelementonthemechanicalpropertiesandconstitutionnearbygrainboundaryinaCo-basesuperalloyCo-22Ni-22Cr-14kduring760℃ageinghasbeeninvestigatedbyAESandmaterialtesting.ResultsshowthatelementLacanbeinastateofsolidsolutionandsegregatesmainlyatthevicinityofgrainboundaries.ThepriorsegregationofLaatomscanaffectsegregationbehaviourofotherelements,sothatexertsinfluenceonmicrostructureofthealloy,ParticularlyincreasingofLacontentcandecreasePconcentrationatthevicinityofgrainboundariesbutnotdecreaseSconcentration.StogetherwithLaproducecosegregationeffect.ThecontentofLahasnoobviouseffectonhightemperaturestrength.WhenthecontentofLacomesupto0.02wt-%,itcanobviouslyimprovethehightemperatureductility.
简介:Mn-Zn铁酸盐(Mn1−xZnxFe2有不同作文的O4)被象pH的如此的合成条件的一起沉淀方法,和影响准备价值,混合答案和NH4他们的微观结构和磁性上的HCO3答案被讨论。样品被X光检查衍射(XRD)和磁化测量仪器描绘。格子参数和综合材料的平均水晶的尺寸与相关软件Jade.5从相应XRD模式被计算。为不同pH价值的样品,当pH价值是7.0,8.0和9.0时,仅仅一个阶段被发现。有7.0的pH价值的样品展出了最高的浸透磁性的正式就职,最低强制力量,和使结晶的最好。为有7.0的pH价值的不同R价值的样品,仅仅一个阶段与R在所有样品,和样品被观察2.3的价值展出了最高的浸透磁性的正式就职和最低强制力量。作文主要有afected磁性的正式就职随Zn(x)的内容的增加增加,但是当x超过0.6时,减少的磁性,和浸透。强制力量的趋势相反是。然而,当x价值直到0.8时,没有磁力被展出。
简介:为了降低ε型六硝基六氮杂异伍兹烷(ε-HNIW)的感度,提出了一种以液态CO2作为反溶剂的新的包覆方法,该包覆方法解决了水悬浮法对溶剂的选择局限性大的问题。对ε-HNIW包覆前后进行SEM、XRD和FT-IR分析,研究表明:选用这种新的包覆方法,氟橡胶、ESTANE和EPDM包覆剂能均匀包覆于ε-HNIW的表面;偶极矩-极性大的包覆剂溶剂使ε-HNIW包覆后转变为α-HNIW晶体;随着包覆剂添加量的增加、或系统压力的降低、或温度的升高,ε-HNIW复合颗粒的分散性越差,球形造型粉颗粒度越好。对ε-HNIW包覆前后进行撞击感度测试表明,相同包覆剂添加量情况下,3种包覆剂降低ε-HNIW感度的大小顺序为:ESTANE〉FE26〉EPDM。
简介:DropletsofCo-37.6wtpctMoandNi-47.7wtpctMoeutecticalloyswererapidlysolidifiedduringcontainerlessprocessingina3mdroptube.Akindofanomalouseutecticappearsinthesetwoeutecticalloyswhenundercoolingisbeyond56and61K,respectively.Thetwoeutecticphasesinanomalouseutecticwereobservedtogrowindendritemanner.Theformationofanomalouseutecticisascribedtothecooperativedendritegrowthofthetwoindependentlynucleatedeutecticphases.Currentdendriteandeutecticgrowththeoriesareappliedtodescribetheobservedprocesses.