学科分类
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18 个结果
  • 简介:Inthisstudy,theweldingthermalcyclecurveexhibitedtwotemperaturepeaksinhighheat-inputtwin-wireseparate-poolsubmerged-arcweldingandcoarse-grainedheataffectedzoneexistedintheweldedjoint.Theinclusionsofprimaryweldmetalandcoarse-grainedheataffectedzoneofCe-addedSAWshouldbeAl203,MnO,Si02,TiO,Ce2S3,CeS,Ce202SandCe203.Undertheeffectofweldingthermalcycle,oxy-sulfidesinclusionsofCe,thediameterofwhichwaslessthan2.0|Jim,slightlygrewlarger,butthecompositionandtypeoftheinclusionsdidn,tchange.ThemicrostructureofthelargeheatinputweldmetalhadacicularferritethatCeoxidesulphideparticlesinducednucleationandproeutectoidferrite.Inthecoarse-grainedheataffectedzoneofweldmetal,home-positionprecipitationofacicularferriteandsympatheticacicularferritewerebothobserved.Itwassupposedthatpreviouscrystalcellsofacicularferriteinaustenitegrainpromotedhome-positionprecipitationofacicularferrite.Meanwhile,sympatheticacicularferritetendedtonucleateattheprimaryacicularferritegrainboundaries,wherehighdislocationdensitywaslocated,andgrewinsidetheneighboringcarbon-depletedausteniticregions.Thegranularbainitenucleatedintheausteniticzonewithhighcarboncontentclosetoacicularferriteandsympatheticacicularferrite.

  • 标签: twin-wire SUBMERGED-ARC welding weld metal with
  • 简介:为确定热加工性能的最佳条件,在温度350~500°C、应变率0.0005~0.5s-1下研究Al6061/Al2O3纳米复合材料的热压缩行为。采用双曲正弦函数得到材料热压缩测试活化能为285kJ/mol。用动态材料模型和相应的加工图,确定了温度450°C、应变速率0.0005s-1和温度500°C、应变速率0.0005~0.5s-1为Al6061/Al2O3材料的热加工性能安全区,最大功率损耗率为38%。由于材料大变形,在温度400°C和应变速率0.5s-1下得到了被伸长和扭结晶粒。

  • 标签: 纳米复合材料 热压缩测试 加工图 动态再结晶 流变失稳
  • 简介:本文阐述了体改性技术在覆铜板中的应用,分析了为什么覆铜板用体需要改性,分析了改性体与树脂结合的机理,对比了非改性体与改性产品在覆铜板中的优劣势,结果表明覆铜板用体未来发展的趋势一定是对体进行表面处理。改性体具有明显的优势:改性体能赋予覆铜板更好的耐湿性,耐热性,抗沉降性,性能均一性,流动性,半固化片表观,层间结合力,机械性能等。经过大量的实践表明,在综合成本上,改性体较非改性体具有明显的优势。

  • 标签: 粉体 覆铜板 耐湿性 耐热性 流动性 层间结合力
  • 简介:Nb-24Ti-18Si-2Al-2Hf-4CrandNb-24Ti-18Si-2Al-2Hf-8Cralloyswerepreparedbyarcmeltinginawater-cooledcrucibleunderargonatmosphere.Microstructuralcharacteristicsandoxidationresistanceofthealloysat1250℃wereinvestigated.Theresultsshowthat,whentheCrcontentis4at%,themicrostructuresconsistof(Nb,Ti)_(ss)andNb_5Si_3;asCrcontentincreasesto8at%,C14LavesphaseCr_2Nbisformed.Theisothermaloxidationtestsshowthattheoxidationkineticsofthetwoalloysfollowsimilarfeatures.Theweightgainsofthetwoalloysafteroxidationat1250℃for100hare235.61and198.50mg·cm~(-2),respectively.Duringoxidation,SiO_2,TiO_2,Nb_2O_5andCrNbO_4areformedatfirst.Then,Ti_2Nb_(10)O_(29)isformedafteroxidationfor20minandbeginstochangeintoTiNb_2O_7astheoxidationproceeds.SiO_2isformedassolidstateatfirstbutlaterevolvesintoglassystatetoimprovethecohesionofthescale.Afteroxidationfor100h,oxidationproductsconsistofSiO_2,TiNb_2O_7,Nb_2O_5andCrNbO_4.

  • 标签: 过共晶合金 氧化行为 NB2O5 LAVES相 显微组织 SiO2
  • 简介:本文基于三轴磁阻传感器HMC5983设计了磁记忆检测探头,研制了基于USB2I2C控制模块的二维金属磁记忆检测系统,以45钢为试验对象开展了金属磁记忆试验研究。通过分析磁记忆二维分量以及其微分分量合成的李萨如图大小,确定试件中存在应力集中的严重程度,试验结果表明:磁记忆二维检测不仅能够准确定位试件中应力集中的部位,而且能够从梯度变化角度对应力集中严重程度进行预判评估。

  • 标签: 磁记忆检测 应力集中 李萨如图 定量评估
  • 简介:2017年1月17日虽然大量的注意力集中在3D打印,但它不是唯一的再制造商可用的增材制造工艺。在关于增材制造的演讲中,来自罗切斯特理工学院的MichaelHaselkorn也谈到了热喷涂、冷喷涂和激光工程化净成型。热喷涂是最古老的增材制造形式,并且是一组利用热源以粉末或线形式熔化材料,然后以高速喷射到表面上的方法。

  • 标签: 增材制造 打印 3D MICHAEL 制造工艺 热喷涂
  • 简介:ThedosimetricphosphorsLi_3PO_4:M(M=Tb,Cu)wereproducedbymodifiedsolid-statemethod.ThestructuralandmorphologicalcharacterizationwascarriedoutthroughX-raydiffraction(XRD)andscanningelectronmicroscope(SEM).Additionally,thephotoluminescence(PL),thermoluminescence(TL)andopticallystimulatedluminescence(OSL)propertiesofpowderLi_3PO_4dopedwithTbandCuwerestudied.ItisadvocatedthatLi_3PO_4:CuphosphornotonlyshowshigherOSLsensitivity(25timesormore)butalsogivesfasterdecayinOSLsignalsthanthatofLi_3PO_4:Tb~(3+)phosphor.Theminimumdetectabledose(MDD)ofLi_3PO_4:M(M=Tb,Cu)phosphorsisfoundtobe21.69×10~(-3)and3.33×10~(-6)J·kg~(-1),respectively.InOSLmode,phosphorshowslineardoseresponseintherangeof0.02-20.00J·kg~(-1).InTLmode,sensitivityofLi_3PO_4:CuphosphorismorethanthatofLi_3PO_4:Tbphosphor.Thekineticsparameterssuchasactivationenergyandfrequencyfactorsweredeterminedbypeakshapemethod,andphotoionizationcrosssectionsofpreparedphosphorwerecalculated.

  • 标签: 辐射剂量 荧光粉 CU TB 扫描电子显微镜 X-射线衍射
  • 简介:ThehotdeformationbehaviorofextrudedAZ80magnesiumalloywasinvestigatedusingcompressiontestsinthetemperaturerangeof250-400℃andstrainraterangeof0.001-1.000s^-1.The3Dpowerdissipationmapwasdevelopedtoevaluatethehotdeformationmechanismsanddeterminetheoptimalprocessingparameters.Twodomainsofdynamicrecrystallizationwereidentifiedfromthe3Dpowerdissipationmap,

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  • 简介:近年来有关于熔融沉积快速成型的技术迅速被普及,3D打印机的使用已经大众化。FDM(熔融沉积成型)3D打印件缺陷的产生极大地阻碍了3D打印使用的发展,论文归纳总结了FDM3D打印件缺陷的种类,并针对各类缺陷分别研究了其处理的方法,最大限度提高3D打印件的质量,减少废品率。

  • 标签: FDM 3D打印 缺陷 产生原因 处理方法
  • 简介:9月25日,察右前旗人民政府与内蒙古福赛金属新材料有限公司签约,该公司拟投资3亿元建设年产10万吨再生锌项目,项目建设地点位于天皮山冶金化工工业园区占地150亩。

  • 标签: 察右前旗 总投资 再生 人民政府 工业园区
  • 简介:据香港统计局4月25日公布的数据显示,由于买家利用金价3月下跌的机会买入黄金,中国大陆当月从香港进口的黄金规模达到2015年12月来的最高水平。

  • 标签: 中国大陆 黄金 香港 进口 数据显示 统计局
  • 简介:p类型(100)上的HfO2电影的乐队排列磁控管劈啪作响种的InP底层被调查。化学状态和系统的结合的特征被X光检查光电子光谱学(XPS)描绘。结果证明没有Hf-P或Hf在里面的存在,有在2在接口的O3和InPO4。紫外分光光度计(UVS)被采用获得HfO2的乐队差距价值。在3d和Hf4f,核心级的系列和原子价系列被采用获得HfO2/InP的原子价乐队偏移量。试验性的结果出现(5.88??T

  • 标签: HFO2薄膜 INP衬底 排列 能带 p型 X射线光电子能谱
  • 简介:TheHAZmicrostructureandperformanceofQuenchingandTemperingmodetemperbeadweldingandgeneralweldedjointswhichweremadeonSA508-3steelof60mmthicknesswerecomparedinthisarticle.Theresultshowsthattemperingsorbitewhichhasexcellentoverallperformancewasobtainedinbothmodes.ThemicrostructureofQuenchingandTemperingmodeweldedjointsgotmorefinegrain.Eventhoughthehardnessoftemperingbeadweldedjointsishigherthanthegeneralone,itstillmeetsthestandardswhichislowerthan350HV.TheimpactabsorbingenergyofeachdistrictoftemperingbeadweldedjointsHAZreached170J,whichisequaltogeneralone.

  • 标签: SA508 -3 steel TEMPER BEAD welding
  • 简介:InordertoimprovethehydrogenstoragepropertiesofLiBH_4-MgH_2composite,twodifferentkindsofNb-basedcatalysts,NbCandNbF_5,wereaddedtoLiBH_4-MgH_2compositebyballmilling,andtheeffectofcatalystsonhydrogenstoragepropertiesofthemodifiedLiBH_4-MgH_2systemwasinvestigated.TheexperimentalresultsshowthatLiBH_4-MgH_2compositeisatwo-stepdehydrogenationprocess,andNb-basedcompoundscanremarkablyenhanceitsdehydrogenationkinetics.Forthecompositewithoutadditionofcatalysts,thestartingdecompositiontemperatureforthefirstdehydrogenationstepisaround320℃,andthereisalongperiodofincubationtime(around220min)fortheoccurrenceoftheseconddecompositionstepevenathightemperatureof450℃.Itneedsmorethan10htocompletethedecompositionprocessandreleasearound9wt%H_2.Afteradditionof5mol%NbF_5,thestartingdecompositiontemperatureforthefirstdehydrogenationstepisaround150℃,thereisnoincubationtimefortheseconddecompositionstep,andittakesaround40mintocompletethesecondstepandreachesatotaldehydrogenationcapacityof9.5wt%.NbF_5hasbettercatalyticeffectthanNbC.Basedonthehydrogenation/dehydrogenationbehaviorsandstructuralvariation,themechanismofcatalyticeffectwasdiscussed.

  • 标签: 储氢性能 铌化合物 催化剂 加氢脱氢 分解温度 复合材料
  • 简介:GrainboundarydiffusiontechniquewithTbH_3nanoparticleswasappliedtofabricateTb-lesssinteredNdFe-Bpermanentmagnetswithhighcoercivity.Themagneticpropertiesandmicrostructureofmagnetsweresystematicallystudied.Thecoercivityandremanenceofgrainboundarydiffusionmagnetareimprovedby112%andreducedby26%comparedwiththoseoftheoriginalmagnet,respectively.Meanwhile,boththeremanencetemperaturecoefficient(α)andthecoercivitytemperaturecoefficient(β)ofthemagnetsareimprovedafterdiffusiontreatment.MicrostructureshowsthatTbelementenrichesinthesurfaceregionofNd_2Fe_(14)Bgrainsandisexpectedtoexistas(Nd,Tb)_2Fe_(14)Bphase.Thus,themagneto-crystallineanisotropyfieldofthemagnetimprovesremarkably.Asaresult,thesinteredNd-FeBmagnetsbygrainboundarydiffusionwithTbH_3nanoparticlesexhibitenhancedcoercivity.

  • 标签: 烧结ND-FE-B磁体 晶界扩散 高矫顽力 纳米粒子 显微组织 热稳定性
  • 简介:Reducingthemanufacturingcostofsolarcellsisnecessarytotheirindustrialproduction.Electrodepositingisaneffective,non-vacuummethodwhichisverysuitableforcuttingthemanufacturingcostofthinfilmsaswellasdevelopingitslarge-scaleindustrialproduction.Inthisstudy,about1-μm-thickCu(In,Ga)Se_2(CIGS)precursorswereelectrodepositedonMo/glasssubstratesinaqueoussolutionutilizingathree-electrodepotentiostaticsystem.Triethanolaminewasusedascomplexingagent,andallparametersofelectrodepositionwerepreciselycontrolled.Afterthat,theelectrodepositedprecursorswereselenizedinaSeatmospherewithdifferentheatingramprates(60and600℃·min~(-1)).High-qualityCIGSfilmswereobtained,andtheircharacteristicswereinvestigatedbyX-rayfluorescence,scanningelectronmicroscopy,energydispersivespectroscopy,X-raydiffraction,Ramanspectraandnear-infrared-visible(NIR-Vis)spectra.Theresultsrevealthattherearemanydifferencesbetweenthepropertiesofthefilmsunderdifferentheatingrates.Finally,CIGSsolarcellswerefabricatedusingafastandaslowheatingrate.Themaximumefficienciesachievedforthefilmsselenizedat60and600℃-min~(-1)are3.15%and0.71%,respectively.

  • 标签: 薄膜太阳能电池 Cu 性能 制备 低成本 X射线荧光分析
  • 简介:TheeffectofAl-3Ti-0.2C-5Sr(wt%)grainrefinerontherefiningperformanceandmodificationofA356alloywasinvestigatedusingopticalmicroscope(OM).ThemorphologyandcrystalstructureofternaryAl-Ti-SrphasesinAl-3Ti-0.2C-5Srrefinerwereanalyzedbyscanningelectronmicroscopy(SEM)andtransmissionelectronmicroscopy(TEM).TheresultsshowthattheternaryAl-TiSrphasesinAl-3Ti-0.2C-5SrrefinercanpromotethegrainrefiningefficiencyofA356alloy.TheternaryAl-Ti-Srphasesco-existintwomorphologies,i.e.,blocky-likephaseandsurround-likephase,besides,whichbothhavethesamechemicalcompositionofAl_(34)Ti_3Sr.ThecrystalstructureofAl_(34)Ti_3Srisface-centeredcubic,andthelatticeparameterisdeterminedtobeabout1.52nm.

  • 标签: A356铝合金 透射电子显微镜 细化效果 三元 扫描电子显微镜分析 A356合金
  • 简介:研究1Cr17Ni2不锈钢中不同δ铁素体相含量变化分别在FeCl3溶液和HNO3+HF溶液中的耐腐蚀行为。通过腐蚀失重率计算及光学金相显微镜、扫描电子显微镜的观察发现:在FeCl3溶液中,δ铁素体的存在减弱了1Cr17Ni2不锈钢的耐腐蚀性能,δ铁素体是优选腐蚀相;而在HNO3+HF溶液中,δ铁素体的存在增强1Cr17Ni2不锈钢的耐腐蚀性能,优选腐蚀相则变成了回火索氏体。通过表面腐蚀形貌表征可以实现反推其受到腐蚀介质环境的性质,为1Cr17Ni2不锈钢腐蚀失效与预防提供可行的方法和依据。

  • 标签: 不锈钢 Δ铁素体 回火索氏体 优选腐蚀