硕士生学位文开题

2005届硕士研究生学位论文摘 要

机械电子工程

论文题目:物理气相沉积Ti-Si-N纳米复合薄膜生长过程的计算机仿真研究

TheSimulationofTi-Si-NCodepositionNanopositeFilms

GrowthwithPVD

研究生姓名:王新蒙

导师姓名:刘学杰教授

专业:机械电子工程

摘 要:

物理气相沉积(PVD)技术作为薄膜材料制备的主要方法之一,其在机械制造业中的应用主要集中在切削刀具表面的强化.Ti-Si-N纳米复合薄膜由于比单一TiN薄膜具有较好的综合机械性能,因此成为硬质薄膜材料研究的主要方向之一.本课题以Ti,Si,N三种粒子共沉积形成的纳米复合硬质薄膜为研究对象,初步尝试用计算机来模拟在单质Ti薄膜和Ti-Si-N三元薄膜生长过程中,入射粒子的吸附,扩散,凝聚成核,团簇长大等行为.通过对模拟结果的分析,来研究沉积过程参数的变化对薄膜微观组织及形貌的影响.

本文在总结蒙特卡罗(MC)和分子动力学(MD)这两种计算机模拟方法各自特点的基础上,采用将微观粒子动力学与MonteCarlo方法相结合的KMC(KiicMonteCarlo)方法来做为本课题研究的计算机模拟方法.该KMC模型引入了活粒子的概念,充分考虑了表面所有活粒子都有发生迁移运动的可能,同时也考虑到每次跃迁运动发生后所引起的周围近邻粒子运动状态的变化.通过给每个团簇赋以不同的颜色,得到了所需的团簇统计数据.本仿真软件的设计是在VisualBasic6.0的集成开发环境中进行,用户可方便地输入待考察的参数值,并实时观察表面粒子的运动状态.

模拟结果表明,在金属Ti膜生长过程中,当基底温度较低时,成核数目较多,但团簇尺寸较小,当基底温度较高时,形成大尺寸团簇的概率增加,团簇之间的空隙较小.模拟数据也显示薄膜表面粗糙度随温度升高而变得光滑.随粒子入射速率的增加,薄膜生长呈现三维岛状生长模式,薄膜表面粗糙度也随之增加.另外,统计结果也显示出,沉积粒子与基底粒子结合力较强.在金属Ti膜仿真结果的基础上,在此项研究中对Ti-Si-N三元薄膜的生长进行情况进行了初步的计算机模拟试验(包括换位机制和不换位机制,激活能参数调节,温度调节等),这使我们对Ti-Si-N形成纳米复合相的机制有了一些了解,并且为进一步的研究奠定了一个很好的基础.

关 键 词:物理气相沉积,计算机模拟,薄膜生长,团簇,动力学蒙特卡罗方法

ABSTRACT

Oneofimportantapplicationsinmachinemanufacturingofphysicalvapordeposition(PVD)isthewearresistancecoatingsofcuttingtools.ThestudyonTi-Si-NternarynanopositioncoatingsbeesahotresearchpointforsearchingnovelhardcoatingsbecauseithasgoodmechanicalpropertiesthansimplebinaryalloyTiN.Inthisresearch,wetrytosimulatefilmgrowthprocessofTicoatingsandTi-Si-Ncoatingswhichformedbyco-depositingTi,SiandNparticles,includingadsorptionofincidenceparticle,diffusion,nucleation,growthofcluster,andsoon.Theeffectsofprocessparametersonmicroscopicstructureandmorphologyofcoatingsarediscussedbyanalyzingthesimulationresults.

Wetrytoimprovethesimulationalgorithm,makeownKMCprograms,andsimulatethemovementofadsorptionparticleonthesurface,whichbasedonanunderstandingofthecharacteristicsandlimitationsofMonteCarlomethodandMolecularDynamicethod.Inourmodel,theconceptofactiveparticleisintroduced.Weconsidernotonlythehoppingpossibilitiesofalltheactiveparticlesonthesurfacebutalsotheinteractionchangeshappenedbetweennearneighbourparticlesaftereveryhop.Wegetstatisticdataofclustersbydistinguishingdifferentcolorswhichclusterspossesed.ThissoftwareisdesignedundertheVisualBasic6.0environment.Usercaninputvariablesconvenientlyandwatchthemovementofparticles.

ForthedepositionprocessofmetalTi,thesimulationresultsshowedthatthenumberofnucleationpointisrelativelargeandthesizeofclustersisallwhentemperatureislow.Bycontraries,thepossibilitiesofforminglargerclusterincreasedandspacingbetweenclustersdiminishedwithclearcrystalboundary.Anddatadisplayedthatroughnessbecameooth.Thegrowthoffilmwasinthemodelof3DVolverWeberandthesurfaceroughnessincreasedwithincidencevelocityraising.Inaddition,statisticaldatashowedstronginteractionforcebetweenadatomandsubstrate.BasedonTifilmsgrowthsimulation,weexecutedthesimulationofTi-Si-Nternaryfilmgrowthunderdifferentconditions,fromwhichwehegotbetterunderstandingabouttheformationofTi-Si-Nnanopositioncoatings.

Keywords:PhysicalVaporDeposition(PVD),ComputerSimulation,FilmGrowth,Cluster,KiicMonteCarloMethod(KMC)

论文题目:基于订单生产的面向地方中小型制造企业ERP系统的研究与开发

ResearchandDevelopmentofERPSystemforLocalSmall

andMediumManufacturingEnterpriseofMaketoOrder

研究生姓名:董晓慧

导师姓名:杨建鸣教授

专业:机械电子工程

摘 要:

ERP,即企业资源计划,是二十世纪九十年怎么发表展起来的综合企业管理信息系统.它代表了未来企业管理的发展方向和必然趋势.随着信息技术的不断发展,中小型制造企业信息化建设变得越来越重要,为了适应当前信息社会激烈的市场竞争,中小型制造企业有必要实施先进的ERP系统来提高企业自身的竞争力,同时,许多中小型制造企业采用的是基于订单生产的生产模式,强调以销定产.那么,如何有效的解决基于订单生产的中小型制造企业资源计划问题,把客户订单的信息有效地导入到生产企业的ERP系统,并及时地生产出客户需要的产品显得尤其重要.本课题针对这一主题展开研究,开发了一套基于订单生产的面向地方中小型制造企业的ERP系统.

论文首先介绍了ERP的发展历程,作用,趋势以及制造业生产类型,特别阐述了基于订单生产的面向地方中小制造企业的ERP软件的开发与研究的内容和目标.重点介阐述了ERP系统的需求分析,系统结构设计,重点是B/S模式和C/S模式相结合的信息系统开发技术,数据库设计,模块结构设计,部分功能界面设计和程序代码实现.

之后,本文介绍了所开发的ERP系统的实施,ERP系统的运行,使用和维护方法.最后论文提出了进一步的研究方向.

关 键 词:ERP订单生产C/SB/S数据库实施

ABSTRACT

ERP,thatisEnterpriseResourcePlanning,isasyntheticenterprisemanagementmessagesystemdevelopedinthe90sof19#century.Itshowsthedirectionandtendencyofenterprisemanagementinthefuture.Withthedevelopmentofinformationtechnology,informationallandmediummanufacturingenterprisebeemoreandmoreimportant.Inordertoadapttothecurrentintensivemarketpetition,theallandmediummanufacturingenterpriseshouldboosttheirpetitiveabilitybyputtingtheenterpriseresourceplanningsysteminpractice.Atthesametimecurrentlymanyenterprises'activitiesarebasedonthemodeofmaketoorder.Theyemphasizeontheneedofcustomers.Soitisimportantforustoeffetelysolvetheenterpriseresourceplanningofmaketoorderbasedallandmediummanufacturingenterprise.Inotherwords,weshouldeffetelyputthecustomer'sorderinformationintotheERPsystemandthentheenterprisesquicklymakethespecificproductsthatcustomersherequired.Themainideaofthesisisstudyandexploreofsystemgearedtolocalallandmediummanufacturingenterpriseofmaketoorder.

Atthebeginningofthisthesis,itintroducesthedevelopment,functionandtendencyinthefunctionofERPandthemanufacturingtypes,especiallydealswithcontentsandaimsofmaketoorderbasedlocalallandmediummanufacturingenterpriseERPsystem.Themaincontentsinclude:ERPsystemdemandanalysis,systemconstructiondesign,especiallyisinformationdevelopmenttechnologybiningB/SwithC/Spatents,databasecreation,systemmodelconstructiondesignandpartsoffunctionsurfacedesignandprogramcodewrite.

Afterthose,thethesisintroducestheimplement,utilizationandmaintenanceoftheallandmediumenterpriseERP.Intheendofthisthesis,conclusionsandprospectsaregiven.

Keywords:ERPMaketoOrderC/SB/SDatabaseImplement

论文题目:超磁致伸缩换能器系统特性的建模与实验研究

TheResearchofModelandExperimentalinMagostrictive

TransducersSystemCharacter

研究生姓名:金璐

导师姓名:张玉宝副教授

专业:机械电子工程

摘 要:

超磁致伸缩材料是一种新型的稀土功能材料,具有磁致伸缩应变大,响应速度快,能量密度高,输出力大等显着特点,它以其优异的性能和良好的应用前景而得到了世界各国研究者们的普遍关注,其相应的理论和应用研究正广泛进行,各种应用器件的开发正成为人们研究的热点.

本论文从课题组现行研制的超磁致伸缩换能器出发,进行了换能器输入输出特性的理论研究与实验研究,力求得到超磁致伸缩换能器更为普遍意义上的数学模型,从而为超磁致伸缩器件的设计提供理论依据与方法,指导超磁致伸缩器件的设计与优化.论文首先对超磁致伸缩材料的特点,特性,器件开发现状,理论研究现状作了详细论述,然后在下面几个方面作了进一步研究:

1.采用有限元软件模拟了ΔE效应对超磁致伸缩棒纵振基频的影响,并定量分析了各种因素对磁场均匀度的影响大小.

2.利用压应力下材料的磁致伸缩与磁化强度的关系,模拟了课题组研制的换能器中超磁致伸缩材料的磁致伸缩性能.

3.根据磁致伸缩产生的机理,结合材料力学及有限元中轴对称结构离散化的相关公式,推导出超磁致伸缩换能器的静态输入输出模型.并利用现有的有限元分析软件ANSYS模拟了换能器输入电流与输出位移的关系曲线.

4.对超磁致伸缩换能器基于物理规律建立起动态特性的数学模型和仿真模型,通过仿真得到系统的响应曲线及各主要参数对换能器动态特性的影响规律.

5.对课题组研制的超磁致伸缩换能器进行了实验研究,检验了静态特性模型与动态特性模型建立的正确与否,同时通过实验找到了现有设计中存在的问题.

关 键 词:超磁致伸缩换能器,系统特性,数学模型,有限元分析,仿真模型,磁机耦合

ABSTRACT

Thegiantmagostrictivematerialisanewfunctionalmaterial,whichhashighmagostriction,rapidresponsevelocity,greatenergydensity,aswellasbigoutputforce.BecauseofthechoicenesspropertiesoftheGMM,manyresearchersoftheworldcountriesnowhetakenpartinstudyingit.Inthemeantime,itscorrespondingtheoryandapplicationsstudiesarebeingprocessed.

Inthisthesis,theinput-outputcharacteristicsofgreatmagostrictivetransducerarediscussed.Thepurposeofreaseachistogetuniversalmathematicalmodelofgreatmagostrictivetransducer,whichcanprovideatheoreticbasiorthedesignofmagostrictiveinstrument.Firstlythethesishasadiscussinaboutcharacteristicandperformanceofthegiantmagostrictivematerial,theactualityofinstrumentexploitationandthestateofacademicstudiesindetail.Moreover,ithaurtherdiscussionsinthefollowingaspects:

1.SimulatetheinfluencethatΔEoffectactonmagostrictiverodbythelimitedcellsoftwareandAnalysetheinfluencingfactoraboutthemagicfieldequality.

2.Simulatethemagostrictivecapacityoftheexployingmagostrictiverodbymakinguseoftherelationbetweenmagostrictionandmagizationintensity.

3.AccordingtothemagostrictivemachaniandtherelatedformulasthatareinTHEMATERIALMACHANICSandTHELIMITEDCELL,deducethestaticstateinput-outputmodelofgiantmagostrictivetransducerandsimulatetherelativecurvebetweenstaticinputsignalandoutputsignalbyusingANSYSsoftware.

4.Establishthedynamicstatemodelaboutgiantmagostrictivetransducersystemthatarebasedonthephysicaldisciplinarian.Gainthesystemresponsecurveandtheeffectlawofdiversifiedparameterthatisactedongainmagostrictivetransducer.

5.Basedontheexistinggiantmagostrictivetransducer,doesaexperimentaboutstaticstatecharacteristicanddynamicstatecharacteristic,whichcanverifythelegitimacyoftransducermathematicalmodel.

Keywords:giantmagostrivtivetransducer,systemcharacteristic,mathematicalmodel,

thelimitedcellanalysis,simulationmodel,thecouplingofmagicmachani.

论文题目:基于神经网络的质量诊断理论的研究与应用

TheResearchandApplicationsofQualityDiagnosisTheory

BasedonNeuralNetworks

研究生姓名:刘华

导师姓名:王建国教授

专业:机械电子工程

摘 要:

产品质量的优劣,是衡量一个国家生产力发展水平以及技术,经济发展水平的重要标志.随着社会的进步和科学技术的发展,人们对产品的质量提出了越来越高的要求.在质量控制过程中,当发现质量发生异常波动时,为了能够及时调整过程参数使得生产过程恢复到正常状态,有必要利用质量诊断方法对生产过程进行诊断.为此,本文针对多指标(变量)多工序过程对质量诊断方法进行了进一步的研究.本文的研究工作主要包括以下几个方面:

绪论中对质量的概念以及质量科学的形成和发展做了简单的介绍,接着分别介绍了单变量统计过程控制的一些方法,主元分析的基本理论和基于主元分析的多变量统计过程控制及其一些改进方法,最后对统计过程诊断的发展状况作了简单的叙述.

介绍了两种质量诊断理论的基本原理,并指出了它存在的一些不足,根据它的不足提出了基于神经网络的两种质量诊断理论,最后将新方法进行仿真研究以验证该方法的有效性.

根据费歇判别分析的基本原理提出了基于费歇贡献图的过程参数诊断方法,并将该方法和主元贡献图方法应用到四水箱过程进行过程参数诊断,最后通过诊断结果比较这两种方法的性能.

简要介绍了CSP生产线的生产流程,并将基于神经网络的质量诊断方法应用到CSP生产线中进行可行性和有效性验证.

最后对全文作了总结,并提出了展望.

关 键 词:质量诊断,主元分析,神经网络,费歇贡献图

ABSTRACT

Thequalityofproductswasanimportantflagtosymbolizethedevelopingleveloftheproductivity,thetechnologyandtheeconomicsinacountry.Withtheadvancementofthesocietyandthedevelopmentofscienceandtechnology,therequirementstothequalityofproductsbeehigherandhigher.Whentheabnormalityoccurredintheprocessofqualitycontrol,itwasnecessarytousequalitydiagnosiethodtodiagnosisproductionlineinordertoadjusttheprocessparameterstimelyandmakequalityparametersreturntothenormalcondition.Inthisthesisthequalitydiagnosiethodsappliedtomulti-index(variable)andmulti-operationprocessweremadeafurtherresearch.Themainworkofthisthesisweredescribedaollows:

(1)Theconceptofqualityandtheformationanddevelopmentofthequalitysciencewereintroduced.thenthemethodsofunivariatestatisticalprocesscontrol,thebasictheoryofprincipalponentanalysis(PCA),multivariatestatisticalprocesscontrolbasedonPCAandsomeimprovementsweredescribedrespectively.Intheendstatisticalprocessdiagnosiethodsweredescribedbriefly.

(2)Thebasictheoryoftwo-kinds-of-quality-diagnosis-theorywasintroduced,thensomedeficienciesintraditionaltwo-kinds-of-quality-diagnosis-theorywerepointedout.Soamethodoftwo-kinds-of-quality-diagnosisbasedonneuralworkswaspresented.Thenewmethodwasparedwiththetraditionalmethodtovalidateitseffectivity.

(3)AnewprocessparametersdiagnosiethodbasedonthefishercontributionplotwaspresentedaccordingtotheprincipleofFisherdiscriminantanalysis.ThenewmethodandPCAcontributionplotwereallappliedtothequadruple-tankprocesstodiagnoseprocessparameters.Thediagnosisresultsshowedthedifferenceofthetwomethods.

(4)TheproductionflowofCSPproductionlinewasdescribedbriefly,thenthemethodofqualitydiagnosisbasedonneuralworkswasappliedtoCSPproductionlinetovalidateiteasibilityandeffectivity.

Finally,thethesiswasconcludedwithasummaryandtheprospectofthequalitydiagnosistheorywasdiscussed.

Keywords:QualityDiagnosis,PCA,NeuralNetworks,FisherContributePlot.

论文题目:基于Web的面向产品开发过程的客车PDM系统的研究与开发

ResearchandDevelopmentofPDMSystemonBus

OrientedtoProductDevelopingProcessBasedontheWeb

研究生姓名:王翠表

导师姓名:李强教授

专业:机械电子工程

摘 要:

分析了国内外产品数据管理系统的特点,结合客车行业的实际需求以及对客车产品开发过程数据信息的全面分析,运用Web技术,分布式数据库技术,面向对象技术,成组技术,开展了基于Web的面向产品开发过程的客车产品数据管理系统的研究与开发.

在对客车行业产品开发部门进行需求分析的基础上,运用软件工程方法,对系统进行了分析与设计,规划了系统实现的网络体系结构,并对其安全策略进行了研究,利用成组技术及相似性原理,对客车零部件进行了合理的分类,建立了客车零件数据库,应用文档管理的方法,对客车产品开发过程中的文档进行了分类管理,建立了图文档数据库,运用ASP和ODBC技术对系统进行了开发,实现了客车产品数据的管理和查询,考虑到该系统是面向产品开发过程的数据管理,其安全性的重要,建立了用户管理子系统,提高了系统的安全性.通过系统实例,给出了应用本系统的过程与方法.

基于Web的面向产品开发过程的客车产品数据管理系统的建立对客车企业的信息化建设具有重要的意义,是客车企业技术部门实现资源共享,数据继承以及并行工程的基础,它的实施将提升客车企业的技术管理水平,为企业CIMS建设打好基础.

关 键 词:客车,产品开发,产品数据管理系统,Web,ASP

ABSTRACT

AnalyzingthecharacteristicofthePDMSinsideandoutsidechina,throughthefactualdemandofthebusvocationandbasedonthewholeanalysisofdatainformationofthebusproductdevelopingprocess,usingWebtechnology,distributeddatabase,Object-Orientedtechnology,andgrouptechnology,theproductdatamanagementsystemonbusorientedproductdevelopingprocessbasedonwebisstudied.

Basedonthedemandanalysisofthedepartmentofproductdevelopmentinbusenterprises,usingthesoftwareengineeringmethod,thesystemisdesigned.Theworksystemstructureofthesystemimplementislaidoutandthesafetystrategyofthesystemisstudied.Usinggrouptechnologyandparabilityprinciple,thebusanditspartsareclassifiedinreasonandbusdatabaseiscreated.Usingthemethodofthedocumentmanagement,thedocumentsinproductdevelopingprocessaremanagedandthedocumentsdatabaseareconstructed.UsingASPandODBCtechnology,thesystemisdevelopedandtheproductdataofthebusianagedandsearched.Becausethedatamanagementsystemisorientedtotheproductdevelopingprocess,thesafetyofitisveryimportant.Useranagementsubsystemisstructuredforenhancingthesafetyofthewholesystem.Bythesystemexample,theprocessandmethodofusingthesystemispresented.

Ithasimportantsignificancetocreatingthedatamanagementsystemorientedtoproductdevelopingprocessbasedonthewebforthedigitalizationofthebusenterprisesandlaysafoundationfortheresourceshare,datainheritandCEofthetechnologydepartmentinbusenterprise.ImplementingthesystemwillupgradethetechnologymanagementandmakethebaseoftheCIMSofbusenterprise.

Keywords:Bus,Productdevelopment,ProductDataManagementSystem,Web,ASP

论文题目:热轧带钢轧机工作辊热应力的研究

ThermalStressStudyofWorkRollinHotStripMill

研究生姓名:韩继铖

导师姓名:任学平教授

专业:机械电子工程

摘 要:

热轧带钢轧机工作辊的热变形直接影响着承载辊缝的形状,从而影响着受轧带钢板型质量的好坏.同时工作辊由于受周期性温度的作用,特别是工作辊表面受到瞬态周期性的热冲击,内部产生热应力.在这些周期性热应力的作用下,工作辊表面会产生热疲劳,产生疲劳裂纹而导致工作辊断裂或失效.因此,定性和定量确定热应力显得尤为重要,准确计算工作辊的温度场是计算其热应力的前提.

在工作辊温度场的求解计算中,由于热传导和热变形行为的复杂性,求解工作辊温度场一直是带钢轧制研究领域的薄弱环节.工作辊温度场的求解方法有解析法,数值法和实测法等,但由于热轧工作辊工作条件极其恶劣和复杂,解析法和实测法等都没有令人满意的结果.因此该领域研究重点是数值法,包括差分法和有限元法.本文就是利用ANSYS有限元分析软件对热轧带钢工作辊的温度场和热应力进行解析.在温度场的计算中采用Solid70热单元进行解析,对工作辊施加第三类边界条件载荷,得出工作辊不同时间的ISO方向温度图和温度等高线图,以及工作辊表面不同深度下的温度分布曲线图.在工作辊热应力计算中,采用Solid45结构单元进行解析,把温度作为载荷施加到结构单元上,得到工作辊径向,轴向,剪切方向以及VonMises等效热应力的热应力等值线分布图.

本文还针对某厂2025热轧带钢轧机工作辊进行了计算机仿真,仿真结果与文献中的实验数据有很好的一致性,从而验证了本文模型计算的正确性.其结果可以为板型控制和工作辊寿命计算分析提供理论依据.

关 键 词:工作辊温度场热应力有限元

ABSTRACT

Thethermaldeformationofhotrolledstripworkrollinfluenceddirectlynotonlytheshapeofrollgapbutalsothequalityofstrip.Itwasshownthatthereweregreaterthermalstresormedwithinworkrollwithperiodicaltemperatureimposed,especiallyinstantaneousthermalimpact.Thethermalstressledtothermalfatigueonrollsurface.Asaresult,thefatiguecrackmadetherollbreakanddisable.Therefore,Itwasimportancethatconfirmthethermalstressqualitativelyandquantificationalandtheaccurateputationoftemperaturefieldwasthebaseoftheputationofthermalstress.

Theputationontemperaturefieldofworkrollwasakeybecauseoftheplexityofthermalconductionandthermaldeformationduringhotstriprolling.Thealgorithmincludedanalyticalmethod,numericalmethodandmeasurementmethod,andsoon.Theouteresultedfromanalyticalmethodandmeasurementmethodweredissatiiedduetothewickedandplicatedworkconditionofworkroll.Soresearchersputanemphasisonthenumericalmethod,whichincludeddifferencemethodandFEM.ThispaperanalyzedtemperaturefieldandthermalstressonthesurfaceofhotrolledstripworkrollerwiththehelpofANSYSsoftware.WeimposedthethirdboundaryconditionloadonworkrollwithSolid70thermalelementresolutionduringputingtemperaturefield.TheresultshowedthatISOdirectiontemperaturechangeswithtime,temperaturecontourline,andtemperaturegraphwithdifferentdepthonthesurfaceofworkroll.Moreover,wegotVonMisesequivalentthermalstresscontourlinegraphinradialdirection,axisdirection,andsheardirectionbyimposingtemperatureloadonstructuralelementwithSolid45structuralelementresolutionduringputingthermalstress.

Ipletedputersimulationof2025hotrolledstripmillworkrollinasteelwork.Theresultaccordedwithactualmeasurementsperfectly,whichprovedtheaccuracyofthesimulationmodel.Theconclusionprovidedananalyticfoundationforstripshapecontrolsandrolllifeputation.

Keywords:Workroll,Temperaturefield,Thermalstress,FEM

材料加工工程

论文题目:快淬Nd-Fe-B永磁体制备工艺与显微组织结构的研究

TheInvestigationorPreparationTechnologiesand

MicrostructuresofMelt-spunNd-Fe-BPermanentMags

研究生姓名:杨在志

导师姓名:任慧平教授

专业:材料加工工程

摘 要:

近几年来,通过熔体快淬工艺制备的粘结Nd-Fe-B永磁体以容易成型,成本低等优点迅速发展起来,目前在永磁市场中所占的比重逐渐扩大,应用领域已经涉及计算机,汽车,马达,通讯和医疗等领域,成为当今社会信息产业和机电产业的基础材料.但是,粘结永磁体一个缺点就是跟烧结永磁体相比,性能较低.其中一个很重要的原因就是磁粉的性能较低.要制备高性能的粘结永磁体必须要有高性能的磁粉.为了提高粘结永磁体的磁性能,本文主要对熔体快淬制备磁粉工艺和永磁体的模压成型工艺进行了研究.

实验通过熔炼技术,真空快淬技术,真空晶化热处理技术及模压成型技术制备了各向同性的粘结永磁体,使用BH磁滞回线测量仪测量永磁体的磁性能.利用扫描电子显微镜(SEM)观察了永磁合金的组织形貌,分析了晶粒尺寸大小对粘结永磁体磁性能的影响.利用透射电子显微镜(TEM)进行了显微组织分析,确定了在永磁合金的组织中有晶体和非晶共存,通过电子衍射对永磁合金中相的晶体结构进行了分析,同时也研究了非晶组织的转变过程中相的变化对磁性能的影响.在实验中还利用了X衍射仪对永磁合金的晶体取向进行了分析.

实验结果表明:用Pr元素代替NdFeB永磁合金中Nd元素,提高了永磁合金的矫顽力,最大值达到了1227KA/m,熔体真空快淬永磁合金的组成有三部分:非晶区,柱状晶区和等轴晶区.当熔体快淬速度为21m/s时,合金中的柱状晶占大多数,柱状晶的生长具有一定的择优取向,该择优取向和永磁合金中的硬磁相的易磁化方向(C轴)一致,高温短时的晶化热处理工艺可以得到晶粒细小,分布均匀的永磁体晶粒,增加了晶粒的界面积,加强了双相纳米晶复合永磁合金的交换耦合作用,提高永磁体的磁性能.高温真空模压成型工艺提高永磁体密度,减小了孔洞体积率,同时模压的过程中,永磁合金磁粉晶粒会有一定取向的转动,有利于提高永磁体的磁性能.

关 键 词:Nd-Fe-B永磁体,磁性能,晶化热处理,熔体快淬

ABSTRACT

Intherecentyears,bondedNd-Fe-Bpermanentmagsweredevelopedrapidlyaorit'oldingeasilyandlowpricebythetechnologyofmeltspinning.Inthesedays,bondedmagshetakenuptheimportantroleatthemarketofpermanentmags.Theyareusedinthemanyfields,suchasputer,car,motor,munication,medicaltreatmentandsoon.Theyhebeethebasematerialsofthemessagesandmachinesindustry.But,bondedmagsheashorting,Magipropertiesislowerthansinteredmags.Themainfactoristhatthepowdersenergyislow.Thehigherpowdersenergiesare,thebetter-bondedpermanentagsis.Inordertoimprovethemagi,thisarticlemainlyinvestigatedthetechnologiesofmagicpowderspreparationanddie-upsettingforbondedpermanentsalloys.

Thepowderorisotropicpermanentsalloyswerepreparedbythetechniqueofmeltingatthehightemperatureandvacuummelt-spunintheexperiment.TheBHhystereticloopapparatueasuredmagicpropertiesofpermanentalloy.SEMwasusedforobservingmicrostructureofalloys,analyzedtheaffectionofcrystallitesincheorthemagicenergiesofthebondedpermanentags.TEMwasappliedforthecoexistencemicrostructureofcrystalandamorphousphase.Thecrystalstructureofphaseswasanalyzedbythewayofelectricdiffraction.Atthesametime,thetranormationsofphasestructureintheprocessofcrystal-treatmentwerestudied,too.CrystaltrendwasexperimentedbyusingX-diffractionapparatus.

Allresultsofexperimentarefollowed:Whentheotherelementsarehomology,somePrelementinsteadofNdmayimprovethecoerciveforceofthepermanentmagsintheNd-Fe-Bpermanentsalloys.Thebestvalueisupto1227KA/m,Melt-spunalloysincludethreeparts:theamorphousarea,thecrystalareaofpoleandtheequal-axiscrystalarea.Whenthevelocityis21m/sofmelt-spun,thepercentofthecrystalareaofpoleisplentiful,theupgrowthofpolecrystaleintobeingthetexture.Theresultofexperimentstatedthatthistextureisthesametoeasymagizationorientationofpermanentmagicalloys,Thefineanduniformitycrystalcouldbegainedbythetechnologyoftheheattreatmentatthehightemperatureforashorttime.Theareaofcrystalboundarywasenhanced,Exchangecouplingwaorefiercenessandthemagiwasimproved,Bythehightemperaturevacuummouldtechnology,thedensityofnanopositepermanentmagicalloyswasimprovedandthevolumefractionofmagswasreduced.Atthesametime,theorientationofcrystallinecanwheelintheprocessofdie-upsetting.Thiswillbebenefitforpermanentalloyagi.

Keywords:Nd-Fe-Bpermanentmags,Magicproperty,Crystallizationheattreatment,Melt-pun

论文题目:水热合成LaAMnO3型钙钛矿及其磁热效应的研究

HydrothermalSynthesisandMagocaloricEffect

ofLaAMnOerovskite

研究生姓名:李解

导师姓名:李保卫教授

协助导师:王正德副教授

专业:材料加工工程

摘 要

室温磁致冷技术因具有代替气体压缩制冷的可能倍受各国关注..与其它磁致冷工质相比,稀土锰钙钛矿材料有以下优势:低磁场下其磁热效应较高,而且化学性质稳定,居里温度可调,电阻率大,成本低,是室温制冷的理想工质.

水热法制备了室温附近磁冷材料—LaAMnO3型钙钛矿(A为Ca,CaBa或CaSr),研究了合成条件(碱度,水热温度,水热时间)对其形貌的影响及-曲线测量仪研究了不同形貌钙钛矿的磁热效应,确定了La0.65Ca0.18Sr0.17MnO3与La0.7Ca0.21Ba0.09MnO3样品的最佳水热合成条件最佳合成条件为:碱度4.16mol/L和6.53～8.9mol/L水热温度240℃以上水热时间80h左右同时找到了影响合成结果的关键性因素—高压釜的密封性,最终改进了工艺:将最初的"水热—热处理"合成工艺变为一步水热即可合成.

水热条件(碱度,水热温度,水热时间)影响钙钛矿成分及形貌,不同形貌的钙钛矿样品,其磁热效应大小有差别:丝状样品比块状样品磁热效应大,而且化学性能更稳定一些采用最佳水热条件一步直接合成的La0.65Ca0.18Sr0.17MnO3样品,很纯其居里温度Tc为323K,最大为0.29KA位离子掺杂对钙钛矿(LaAMnO3)的磁热均有影响对于不同系列的La1-xAxMnO3型钙钛矿样品,其居里温度Tc与A位离子掺杂量x之间的规律性不同采用最小二乘法回归出La0.65Ca0.35-xSrxMnO3La0.7Ca0.3-xBaxMnO3拟合曲线和.依据这样的曲线规律,很容易制得室温附近的成分不同的钙钛矿样品,并能预测已知成分钙钛矿样品的居里温度.关 键 词:水热合成钙钛矿磁热效应居里温度Nownear-roomtemperaturemagicrefrigeranttechnologyiorefocusedonbymanycountrieoritsreplacinggaspressioninthefuture.InnerMongoliaUniversityofScienceandTechnologyhadcooperatedwithBaotouResearchInstituteofRareEarthforsixyearsonthestudyofDevelopmentofMagicRefrigerantTechnology.Thisthesisbelongstothestudyitemanditainpurposesaretoprepareandstudynear-roomtemperaturemagicrefrigerantmaterialsandsupplymaterialormodemachinefinally.

Inparisionwithothermagicrefrigerantmaterials,rare-earthmanganeseperovskitehassuchadvantagesashighmagocaloriceffectatlowmagicfield,goodchemicalstability,tunableCurietemperature,largeelectricalresistivityandlowcost.Itisanidealnear-roomtemperaturemagicrefrigerantmaterial.

Inthiswork,thenear-roomtemperaturemagicrefrigerantsamplesofLaAMnO3(AisCa,CaBaorCaSr)seriesperovskitewerepreparedbyhydrothermalmethod.Theinfluencesofpreparedconditions(alkalinity,hydrothermaltemperature,hydrothermaltime)ontheirmineralposition,shapesandthemagocaloriceffectsofdifferentshapes'perovskitesamplesandtheirhightemperaturehotstabilitieswerestudiedbyXRD,SEM,TEM.ThemagicaloriceffectsandtheCurietemperaturesofsamplesweremeasuredby-curvemeasurementdevices.TheoptimalhydrothermalconditionsofLa0.7Ca0.21Ba0.09MnO3andLa0.65Ca0.18Sr0.17MnO3weremadecertain.Theiroptimalhydrothermalconditionsare:alkalinityis4.16mol/Land6.53～8.9mol/Lhydrothermaltemperaturearebothover240℃,hydrothermaltimearebothabout80h.Atthesametime,thekeytoinfluencingtheexperimentresultthehermeticityofautoclewaound.Atlasttheprocesswasimproved:turning"hydrothermalandheat-treatedsythesis"into"one-stephydrothermalsythesis".

Thepreparedconditions(alkalinity,hydrothermaltemperature,hydrothermaltime)heinfluencesontheirmineralposition,shapes.Themagicaloriceffectsofdifferentshapesamplesarenotsame:themagicaloriceffectsofsilk-samplessynthesizedunderoptimalhydrothermalconditionsarelargerandtheirhightemperaturechemistriesaremorestablethanthoseoflump-samplessynthesizedundertheotherconditions.La0.65Ca0.18Sr0.17MnOowderswhichwerepreparedbyone-stephydrothermalmethodarepureperovskite,whoseCurietemperature(Tc)is323Kandmaximalis0.29Katthemagicfieldof1.4Tesla.A2+contentheinfluencesonthemagocaloriceffectsandCurietemperatures(Tc)oftheperovskitepowders.DifferentseriesLaAMnOerovskitehedifferentregularitiesbetweenCurietemperature(Tc)andA2+content.Byleastsquaremethod,La0.65Ca0.35-xSrxMnO3andLa0.7Ca0.3-xBaxMnOerovskite'fittingcurveswereregressedrespectively:and.Accordingtosuchcurves,itiseasytopreparenear-roomtemperature,differentpositionperovskitesamplesandforecasttheCurietemperaturesofgivenperovskitesamples.

Keywords:hydrothermalsynthesisperovskitemagocaloriceffectCurietemperature

论文题目:粘结NdFeB永磁材料组织结构和磁性能研究

TheStudiesofMicrostructureandPropertiesofBondedNdFeBMag

研究生姓名:周维娜

导师姓名:李文学教授

专业:材料加工工程

摘 要:

为了充分发挥我国稀土资源优势,发展我国的NdFeB稀土永磁产业,本文比较系统地研究了模压成型粘结NdFeB永磁体制备过程中的相关问题,包括磁粉的粒度分布,粘结剂含量,成型压力对NdFeB磁体磁性能的影响,以及对无粘结剂热压成型工艺的探索.在不同工艺条件下制备粘结磁体,利用NIM-2000H磁性能测试仪,PW1700x射线衍射仪和QUANTA400型扫描电子显微镜等测试分析手段,研究了各个工艺参数对NdFeB磁性材料磁性能的影响.在大量实验的基础上制备出了Br等于0.714T,Hcj等于721kAm,(BH)max等于86kJm3的磁体.

通过理论研究,得到了粘结磁体原料配比与组分参数间的关系,磁性能与组分组成间的定量关系表述,压制过程中粉末的运动规律,磁体在空间所产生磁场的理论公式.这些结果为磁体制备和磁体使用前设计提供了理论依据,避免了工作的盲目性,

通过大量的实验研究表明,不同尺寸的颗粒按一定比例混合可以适当提高磁性能,当混合情况为:100目与80目磁粉的质量比是1:0.45时,再把混合磁粉与200目磁粉按质量比为1:0.5的比例混合,可以明显提高磁体的密度和磁性能.与磁性相体积分数变化趋势相同,磁体性能随粘结剂含量增加呈现先提高后降低的规律,当粘结剂与磁粉质量比为3%～4%时磁性能最佳.成型压力是工艺参数中最敏感的因素之一,成型压力的增加对磁体的性能而言有利,但考虑到实际设备和模具的承受能力,本实验获得的最佳的成型压力是730Mpa.

关 键 词:粘结NdFeB粘结剂粒度分布成型压力磁性能

ABSTRACT

Tomakeexertionsoftherareearthadvantageofourcountryandtoimprovethemagicindustry,thispaperpresentsparativesystematicresearchofproblemsinthepreparationofeconomicalmouldpressingbondedNdFeBpermanentmags.ThebondedmagfromrapidquenchedNdFeBhasbeenproduced,andtheinfluenceofthetechniquefactorssuchascouplingagent,couplingprocess,powderparticlesize,binder,solidificationprocess,formationprocessonitspropertieshasbeenanalysisedbymeansofNIM-2000Hmagicpropertiesanalysis,PW1700x-raydiffraction,andQUANTA400SEM,etc.Fromalotoftests,thebondedNdFeBmagwithhighpropertieshebeenpreparedbyrapidquenchedpowder,andthemechanicandmagicpropertieswithBr等于0.714T,Hcj等于721kAm,(BH)max等于86kJ.

Severalformulationsaregiveninthearticle.Theyshowmanyrelationships,suchastherelationshipbetweenponentratioandgeometricalsizeofinstitutes,therelationshipbetweenmagpowderandthevolumepercentageofmagpowder,andtherelationshipbetweenpowdermovementanddensity.Theseformulationakethingsconvenientforthepre-designofmag.

Experimentsprovedthatthemixtureofdifferentsizeofpowdercanimproveitsproperties.Itisbettertomix100meshand80meshas1:0.45,thenmixtheformermixturewith200meshwithratioas1:0.5.Whenthecontentofbinderwaschanged,themagicpropertiesarefollowingthesamelawasthedensity.Thebestrangeofthecontentofbinderis3%～4%(Wt.).Mouldingpressureisthemostimportantfactor,highpressurecanincreaseitsproperties.Butthediewouldbedestroyedbypressure,sothebestpressureis730Mpa.

Keywords:bondedNdFeB,binder,particlesize,pressure,magicproperties

论文题目:废塑料作为高炉喷吹辅助燃料的基础性研究

FundamentalStudyofInjectingPlasticScrapasAssistant

FuelintoBF

研究生姓名:陈伟鹏

导师姓名:朱蒙教授

专业:材料加工工程

摘 要:

本文对废塑料作为高炉喷吹辅助燃料做了基础性的研究.由于废塑料成分复杂,所以选择了聚丙烯等五种典型塑料分别进行研究.采用热分析仪,分析不同塑料试样分别在惰性气氛和氧化性气氛中恒速升温条件下热失重过程中的吸热与放热情况.采用热重法研究了聚丙烯等五种塑料分别在氧化性气氛和惰性气氛中恒速升温条件下和恒温条件下的热失重特性.采用碘量法和硝酸银滴定法检测了PVC燃烧气体产物中Cl的存在形式,并就其对高炉煤气洗涤系统的影响进行了讨论.采用X射线衍射仪fundamentallystudiedinthepaper.Becauseponentofwasteplasticisveryplex,fivekindsofmodelplasticshebeenselectedtobestudied.DecalescenceandegressofheatofdifferentplasticswasstudiedatconstanttemperatureandduringrisingintemperatureonconstantrateinoxidizingandprotectiveatmospherebyDTA.ThermogrimetriccharacteristicofplasticscrapwasstudiedbyTGatconstanttemperatureandduringrisingintemperatureonconstantrateinoxidizingandprotectiveatmosphere.ChlorideinbustionproductofPVCweremeasuredbyiodometricmethodandlunarcaustictitration,moreovertheinfluenceofChlorideonwashingdeviceofcoalgaswerediscussed.ComponentofsalvagestoreswasanalysedbyXRD

Thereslutesshow:Heatenduranceofdifferentplasticsaredifferent,subsequenceofheatenduranceofdifferentplasticsinN2:LPE,PP,ABS,PVC,PA6.Heatenduranceofdifferentplasticsaredifferent,subsequenceofheatenduranceofdifferentplasticsinair:LPE,PP,ABS,PVC,PA6.ThermogrimetriccurveofPVCistwo-part,firstClseparatefromPVC,secondanicmatterlossofweight.Speedoffirstreactioniasterthansecondreaction.thermogrimetriccharacteristicofplasticscrapiittingforfirst-orderreactionatoxidizingandprotectiveatmosphere.Itisailtopromoteweightlosstoelevatetemperatureandoxygencanpromoteweightlossofplasticscrap.PlasticscrapcanquicklyburntincyclotronareaofBF.Thereisahypothesisthateragetemperatureis1800℃inbackspinareaofblastfurnace,Calculatedbustiontimeofdifferentsamplesare40～71mswhenbustionrateis80%.Whentheweightofinjectedplastic(18%PVC)islessthan3.60kg/t.Fe,washingdeviceofcoalgascan'tbeeroded.CombusitionresidueofPA6areSiO2andC.CombusitionresidueofPVCareC22H14,Ca(ClO3)2,CaCO3,C.

Keywords:wasteplastic,injectingforblastfurnace,TG,PVC

论文题目:固体氧化物燃料电池Cu基阳极的制备与性能研究

PerparationandPerformanceofSolid-oxideFuelCellCu-based

Anodes

研究生姓名:彭军

导师姓名:安胜利教授

协助导师:宋希文副教授

赵文广副教授

专业:材料加工工程

摘 要:

化学共沉淀法可以制备比表面积大,颗粒小,分散良好,烧结体电导率高的固体电解质纳米粉末,但其成本较高且周期长,工作量大,低温燃烧合成法可以达到相同的效果,而且成本低,效率高.固体氧化物燃料电池用Ni加电解质作为阳极,在H2作为燃料时性能较好,但是用碳氢燃料时,由于Ni催化碳的沉积,使电池效率急剧下降,甚至由于碳的生长会破坏电池.Cu是一种惰性金属,对碳氢化合物的沉碳反应没有催化作用,是一种可能的固体氧化物燃料电池阳极材料.

采用低温燃烧合成法制备了氧化钐,氧化钆二元稀土掺杂氧化铈纳米粉体.利用DTA/TG热分析对硝酸铈/柠檬酸胶体的燃烧反应进行了研究,胶体的点火温度约为230℃.利用XRD和BET等现代物理测试方法对氧化铈纳米粉体的物相和比表面积等性能进行了表征,650℃焙烧的粉体具有立方萤石结构,高的比表面积,粉体的比表面积在41.116-23.847m2/g之间,平均颗粒直径为20.268nm-34.945nm,呈良好的分散状态.利用交流阻抗法测试了材料的电导率.结果表明,(CeO2)0.8(Sm2O3)0.08(Gd2O3)0.02固体电解质的电导率高最,900℃时达0.0973S·cm-1.

采用涂层法制备了Cu-CeO2基阳极燃料电池.利用恒电位法研究了阳极中Cu含量对阳极电导率的影响,得出CuO含量在不小于50%时,阳极中Cu才能形成连续的网络结构.利用能谱和线扫描对Cu烧结扩散进行了研究,发现对于Cu基阳极,在制备阳极时烧结温度不能超过1130℃,超过此温度后Cu向电解质扩散剧烈.

在H2气氛下测试了Cu基阳极固体氧化物燃料电池的性能.首先利用能谱和线扫描研究了700℃下阳极中Cu扩散行为,在此温度下Cu可以向电解质扩散,但速度非常缓慢,为沿晶扩散,并利用SEM研究了Cu颗粒长大情况,发现在650-850℃温度段Cu颗粒长大趋势小.利用Solartron1287A恒电位仪和Solartron1260A阻抗普仪测试电池V-I,W-I曲线及电池交流阻抗谱,得出Cu50%的阳极输出功率大,极化小,CeO2对阳极电化学反应有良好的催化作用.

关 键 词:低温燃烧合成,电导率,扩散,燃料电池,极化

ABSTRACT

ChemicalCo-precipitationcansynthesizenano-powdersofsolidelectrolyte,ithashighspecificsurfacearea,allparticlesize,highdispersionbehiours,andthesinterhashighionicconductivity,butthiethodhashighcost,longcycleandgreatworkload.Thelowtemperaturebustionsynthesiscanobtainsametarget,moreover,haslowcostandisefficient.Solidoxidefuelcell(SOFC),hasaanodethatianufacturedbyaNi-electrolyteposite,isveryefficientwithhydrogen,butwitnhydrocarbonuel,Nickelhasahighcatalyticactivityforthedehydrogenationofthehydrocarbons,thustheefficiencyoftheSOFCsharplydeteriorate,andeventhecellisdestroyedbecausethecarboncontinuallygrowup.Copperisinertforcarbonformation,andispotentialanodematerialofSOFC.

TheSm2O3,Gd2O3dopedCeO2nano-powdersweresynthesizedbythelowtemperaturebustionsynthesis.Differentialthermalanalysis/themogrimertryanalysisresultsshowthattheignitingtemperatureofceriumnitrateandethyleneglycolredoxmixtureisabout230℃.ThephaseandspecificsurfaceareaofthedopedceriapowderswerecharacterizedbyXRDandBET,Theresultsshowthatdopedceriapowderscalcinedat650℃heacubicfluoritestructure,highspecificsurfaceareathattherangeofthespecificsurfaceareairom23.847m2/gto41.116m2/g,aneragesizeof20.268nmto34.945nm,andahighdispersionbehiours.TheionicconductivityofdopedCeriaelectrolytesweremeasuredbythea.cimpedancespectroscopytechnique.theresultsshowthat(CeO2)0.8(Sm2O3)0.08(Gd2O3)0.02solidelectrolytehasahighconductivity.itsconductivityis0.0973Scm-1at900℃.

Cu-CeO2-basedanodefuelcellianufacturedbycoating.theTherelationbetweenconductivityofanodesandtheCucontentofanodesisstudiedbyPotentionstaticmeans.theresultsshowthatthecopperofanodeformcontinuoueshworkstructurewhentheCucontentisnotlessthan50%.ThediffusionofCuwhenanodeandelectrolyteweresinteredwerestudiedbylinescanningandenergyspectrum.Wediscoveriedthatthetemperaturecann'tbeabove1130℃whenanodewassintered,ifthesintertemperaturewashigherthan1130℃,copperwillacutelydiffuseintoelectrolyte.

TheperformanceoftheCu-CeO2-basedanodessolidoxidefuelcellwastestedwithH2.ThediffusionofCuincellsat700℃wasstudiedbylinescanningandenergyspectrum.Theresultsindicatethatcoppercandiffuseintoelectrolyteatthistemperature,butthevelocityofdiffusionisveryslow,anditsdiffusionisintercrystalinediffusing.Thegrowthofcoppergrainwasresearchedbyscanningelectronmicroscopy(SEM).Wefindedthatthetrendofthecoppergraingrowthisveryslowatwhenthetemperaturerangefrom650℃to850℃.TheV-I,P-I,thea.cimpedancespectroscopyofcellswastestedbytheSolartron1287APotentiostatandtheSolartron1260AImpedance/Gain-phaseAnalyzer.Theresutsshowthatwhencoppercontentis50%thefuelcellhashighouputpowerandlowpolarization,andwefindedthatCeO2hasahighcatalyticactivityforelectrochemicalreactionofanode.

Keywords:Lowtemperaturebustionsynthesis,conductivity,diffuse,fuelcell,polarization

论文题目:磁性形状记忆合金Ni-Mn-Ga的相变研究

StudyofPhaseTranormationInNi-Mn-GaMagic

ShapeMemoryAlloys

研究生姓名:王志成

导师姓名:赵增祺教授

专业:材料加工工程

摘 要:

Ni-Mn-Ga合金是Heusler合金中唯一兼有铁磁性和形状记忆效应的材料.通常的形状记忆合金是非铁磁性的,其形状和尺寸的变化受控于温度和应力.Ni-Mn-Ga合金的形状记忆效应除了受温度,应力的影响外,还可以通过磁场来控制.利用磁场改变马氏体的取向,可以产生大的磁感生应变.这一性能特点决定了这种材料在传感和驱动元件中发挥突出的作用,所以受到人们的普遍关注.然而,该材料相变行为复杂,磁感生应变不稳定,力学性能和加工性能差以及居里温度偏低等原因使其应用受到限制.本文针对Ni-Mn-Ga合金存在的实际问题,从多晶材料入手,研究了稀土在材料改性方面的作用,同时探讨了磁感生应变,Tb提高合金力学性能的机制.重点研究了以下几个方面:

系统的研究了Ni50Mn29Ga21Tbx(x<,1)合金的晶体结构.实验结果表明,室温下,Ni50Mn29Ga21Tbx(x<,1)合金的晶体结构属于非调制型马氏体,稀土元素Tb的加入并没有改变Ni50Mn29Ga21的结构类型.

研究了Ni50Mn29Ga21Tbx(x<,1)合金的金相组织.实验结果表明,稀土元素Tb的加入明显的减小了合金的晶粒尺寸,同时Tb主要聚集在晶界上,在晶内有零星的分布.

研究了Ni50Mn29Ga21Tbx(x<,1)合金的相变特性.非化学计量的Ni50Mn29Ga21Tbx(x<,1)比化学计量Ni2MnGa有更高的马氏体相变温度.

研究了Ni50Mn29Ga21Tbx(x<,1)合金的力学性能.稀土元素Tb的加入可以显着的提高合金的力学性能,其原因有两方面:一方面,Tb的加入降低了对合金抗弯性能起有害作用的氧,硫等元素杂质,另一方面,Tb的加入起到了细化晶粒的作用.

研究了Ni50Mn29Ga21Tbx(x<,1)合金的磁学特性.稀土元素Tb的加入对合金的居里温度和饱和磁化强度基本没有影响.

研究了Ni50Mn29Ga21Tbx(x<,1)合金的磁感生应变性能.稀土元素Tb的加入最初可以使合金的磁感生应变性能提高,但是当x>,0.1后,合金的磁感生应变性能开始下降.

总之,稀土元素Tb的加入使得Ni2MnGa合金的马氏体相变温度和力学性能提高,同时基本保持其他的性能不变,展示了较好的应用前景.

关 键 词:Ni-Mn-Ga合金,稀土元素Tb,晶体结构,力学性能

ABSTRACT

Ni-Mn-GaalloyistheonlyonethatbothferromagicandshapememoryeffectamongHeusleralloyfamily.Inmostcasesshapememoryalloysarenonmagicandtheoptionstoinfluencetheirshapeanddimensionsarerestrictedtotemperatureandstress.InNi-Mn-Ga,however,thechangeintheshapeanddimensionscanbeinfluencedbyanexternalmagicfiledinadditiontotemperatureandstress.Thealloydemonstrateslargemagic-field-inducedstrains(MFIS)basedonreorientationofmartensitevariantsinmagicfield.Thischaracteristicwillmakethealloyacandidateofidealartdrivingmaterials.ThusNi-Mn-Gaalloyhasbeenreceivedmuchattention.However,alltheplexityofphasetransition,unstableMFIS,mechanicalpropertyandprocessability,andlowerCurietemperatureofthealloygreatlylimititsapplication.Inviewofthissituation,andconsideringpolycrystallinematerials,effectofrareearthonmodificationandphysicalessenceandmechaniofMFISandbendingstrengthhebeenstudied.Themajorresearcheffortsaollows:

TherewasnoobviouseffectofrareearthmetalTbonNi50Mn29Ga21Tbx(x<,1)alloys'crystalstructures.TheadditionofTbdidnotchangethecrystalstructureofNi50Mn29Ga21andatroomtemperaturethecrystalstructurewasnon-modulatedtype.

TheadditionofTbcouldremarkablydecreasesizeofgrainsandmostofTbgatheredontheborderofgrains.Besidesthat,therewasalittlequantityofTbseparatedinthegrains.

Ni50Mn29Ga21Tbx(x<,1)hemuchhighermatensitephasetranormationtemperaturethanNi2MnGa.

TheadditionofTbhasnoeffectonCurietemperatureandmagization.

BendingstrengthofthealloysincreasedbecauseoftheadditionofTb.Thereweretworeasons:firstly,theadditionofTbremovedtheelementssuchasO,Swhichwereharmfultomechanicalproperty,Secondly,theadditionofTbfinedthegrains.

WiththeadditionofTb,MIFSincreasedatfirstandwhenx>,0.1itdecreased.

Inshort,theadditionofTbcouldremarkablyimprovepropertiesofmechanicandphasetransitionwhileotherpropertiescouldkeepconstant,thereforethealloysshowedaprospectivepracticefuture.

Keywords:Ni-Mn-Gaalloy,rearearthTb,crystalstructure,mechanicalproperty

论文题目:快淬La-Mg-Ni系贮氢合金结构与电化学性能的研究

TheInvestigationonStructuresandElectrochemicalPerformances

ofMelt-spinningLa-Mg-NiBasedHydrogenStorageAlloys

研究生姓名:董小平

导师姓名:张羊换教授

专业:材料加工工程

摘 要:

随着科技的进步,环保意识的加强,移动电子产品的日益小型,轻质化,要求小型高容量Ni/MH电池配套,众所周知AB5型贮氢合金的容量已接近其理论值,进一步提升空间较小.这就促使开发有更高能量密度的新一代贮氢电极合金.对于提高容量来说,最具希望的合金之一是La-Mg-Ni系(PuNi3型)合金,但此类贮氢合金存在的主要问题是电化学循环稳定性较差.因此,开展对此系列合金的系统研究,具有重要的学术价值和良好的应用前景.

本文主要应用熔炼法和真空快淬技术制备了La-Mg-Ni系合金,用开口式三电极系统测试了合金的电化学性能,用XRD分析了合金的相组成及相结构,用SEM和光学显微镜观察了合金的微观组织形貌,用TEM观察了快淬态合金的形貌并用SAD确定其晶态.全面系统的研究了快淬工艺对贮氢合金微观结构及电化学性能的影响,得到如下一些主要结论:

1.综合研究了铸态及快淬态La2Mg(Ni0.85Co0.15)9Mx(M等于B,Cr,x等于0,0.05,0.10,0.15,0.20)合金的微观结构及电化学性能.结果表明,B,Cr的加入导致铸态合金的容量下降,快淬使不含硼合金的放电容量随淬速的增加而单调减少,含硼合金的容量随淬速的变化有一个极大值,这主要是由于快淬使Ni2B相消失,从而使LaNi2相的量下降.快淬工艺与B,Cr的加入不同程度的改善合金的循环稳定性,这主要是由于快淬使合金的晶粒细化和非晶相的形成所致.

2.研究了合金La2Mg(Ni0.85-xCo0.15Cux)9(x等于0,0.02,0.05)的微观结构及电化学性能,结果表明,随Cu含量及淬速的增加,合金的容量降低,这主要是由于快淬导致的晶格应力增加以及非晶相的形成.快淬使合金晶粒细化以及非晶相的形成是合金的循环寿命提高的重要原因.

3.导致贮氢合金失效的主要原因是在电化学循环过程中的氧化腐蚀,非晶相的形成能有效的提高合金在腐蚀性电解液中的抗氧化腐蚀性能.因此提高合金表面的抗腐蚀能力是提高La-Mg-Ni系(PuNi3型)贮氢合金循环稳定性的关键.

关 键 词:快淬,La-Mg-Ni系(PuNi3型)贮氢合金,微观结构,循环稳定性

ABSTRACT

Themobileelectronicdevicesincreasinglylessenandlightenwithadvancementofscienceandtechnology,strengthenofenvironmentalprotectionconsciousness.Ni/MHbatteryrequireini-typeandhighcapacity.Asweallknow,thedischargecapacityofcurrentlyadvancedAB5-typeelectrodealloyisapproachingitstheoreticalone,itseemstobeverydifficulttofurtherincreasethecapacityoftheAB5-typehydrogenstoragealloy.Therefore,newertypealloyswithhigherenergydensityareurgentlyneededtoreplacestheconventionalrare-basedAB5-typealloy.OneofthemostpromisingcandidatesistheLa-Mg-Nisystem(PuNi3-type)forincreasingthecapacity,butithasonemainquestionthatLa-Mg-Nisystemelectrodehaspoorcyclestability.Therefore,prehensiveinvestigationofLa-Mg-Nisystem(PuNi3-type)alloyhassignificantacademicvalueandexcellentapplicationfuture.

La-Mg-Nisystem(PuNi3-type)hydrogenstoragealloyswerepreparedbycastandrapidlyquenchedtechnologyatvacuumatmosphere.Theelectrochemicalperformancesoftheexperimentalalloysweremeasuredbyanopentri-electrodesystem.Themicrostructuresoftheas-castandquenchedalloyswerestudiedsystematically:thephasestructureswereanalyzedbyXRD,themicrostructuresandmorphologiesofthealloyswereobservedbySEMandOpticicroscope,Thecrystallinestateandmorphologiesoftheas-quenchedalloysweredeterminedbyTEMandSAD.Theinfluencesofrapidlyquenchedtechnologyonthemicrostructuresandelectrochemicalperformancesoftheexperimentalalloyswereresearchedindetail,andsomeimportantconclusionwereobtained:

1.Themicrostructuresandelectrochemicalperformancesoftheas-castandquenchedLa2Mg(Ni0.85Co0.15)9Mx(M等于B,Cr,x等于0,0.05,0.10,0.15,0.20)alloysweresyntheticallyinvestigated.TheobtainedresultsshowthattheadditionsofB,Crdecreasecapacityoftheas-castalloy.Thedischargeoftheas-quenchedalloywithoutboronmonotonouslydecreaseswiththeincreaseofquenchingrate,whereasthedischargecapacityoftheas-quenchedalloycontainingboroncanattainamaximumvalueforagivenquenchingrate.ItisascribedtorapidquenchingleadstoadistinctdecreaseoftheNi2Bphase,anddecreasestheamountoftheLaNi2phase.RapidlyquenchedtechnologyandtheadditionsofB,Crcanslightlyenhancethecyclestabilityofthealloy,itiainlyattributedtotheformationofgrainrefinementandamorphousphaseproducedbyrapidquenching.

2.Themicrostructuresandelectrochemicalperformancesoftheas-castandquenchedLa2Mg(Ni0.85-xCo0.15Cux)9(x等于0,0.02,0.05)alloyswereinvestigated.TheobtainedresultsshowthatthecapacityofthealloydecreaseswiththeincreaseofCucontentandquenchingrate,thisiainlyattributedtotheincreaseofthelatticestressandtheformationoftheamorphousphaseafterrapidquenchingtreatment.Theimportantcauseofenhancingthecyclelifeofthealloyistheformationofgrainrefinementandamorphousphaseproducedbyrapidquenching.

3.ThecausesleadingtotheLa-Mg-Nisystem(PuNi3-type)hydrogenstoragealloyefficacylossistheoxidationandcorrosionofthesurfaceofthealloyelectrodeinprocessoftheelectrochemicalcycling.Theformationofamorphousphasecaneffectivelyimprovetheanti-oxidationandcorrosioncapabilitiesofthealloyimmergedincorrosiveelectrolyte.Therefore,thekeytoenhancethecyclestabilityoftheLa-Mg-Nisystem(PuNi3-type)hydrogenstoragealloyadvancestheanti-oxidationandcorrosioncapabilitiesofthesurfaceofthealloy.

Keywords:Rapidlyquenched,La-Mg-Nisystem(PuNi3-type)Hydrogenstoragealloy,Microstructure,Cyclestability

论文题目:CSP薄板坯连铸连轧层流冷却过程温度场数值模拟

NumericalSimulationforTemperatureFieldofCSPThi

SlabContinuousCastingandRollingLaminarCooling

研究生姓名:李东锋

导师姓名:曹建刚教授

专业:材料加工工程

摘 要:

薄板坯连铸连轧技术目前已进入工业大生产行列,并取得显着的经济效益,有着广阔的发展前景.因此对与此技术相关的课题的研究有着十分重要的意义.

CSP生产线上常用的冷却方式是层流冷却.热轧后的层流冷却过程不仅降低了板带温度,更为重要的是奥氏体的分解基本在此过程中发生.根据冷却制度的不同,热轧后的变形奥氏体可以转变为不同的组织和不同的晶粒尺寸.所以层流冷却过程是CSP生产过程中十分重要的环节.

本论文针对包头钢铁集团公司的CSP层流冷却生产线的实际情况,综合分析了在层流冷却过程中热轧钢板的换热情况.热轧钢板从精轧机出来到地下卷取机之间的冷却过程可以分成喷淋水冷却段与空冷段两部分分别加以考虑.在喷淋水冷却段根据冷却水与热轧钢板的实际换热情况,又将其细分为冲击区与非冲击区两部分分别加以对待.最终得出各种换热条件下的换热系数经验公式,将其作为温度场数值模拟计算中的边界条件.

在数值计算中,奥氏体分解所释放的相变潜热采取等价比热容法进行处理.材料的热物性参数,除密度受温度影响不大取为常数之外,其他参数都作为温度的函数进行处理.

温度场数值模拟计算的结果表明:在层流冷却过程中所释放的相变潜热使轧件卷取温度明显升高,随着轧件厚度的增加,内外冷却不均,轧件内外温差明显增大,轧件的运行速度增加使卷取温度升高的原因主要是冷却时间的减少,而不是换热系数的增大,增大冷却水的水流密度,降低冷却水的温度都会使轧件与冷却水之间的换热系数增大,从而使轧件的卷取温度降低,但相比之下,冷却水温度的降低对换热的影响更为剧烈.

关 键 词:CSP层流冷却温度场数值模拟

ABSTRACT

Thinslabcontinuouscastingandrollingtechnologyhasalreadyenteredtheindustrialgreatproductionranksatpresent,andhaaderemarkableeconomicbenefits.Ithaserywidedevelopmentprospects.Sostudyingthesubjectcorrelatingwiththistechnologyhasveryimportantmeaning.

LaminarcoolingionlyusedonCSPproductline.ItiseryimportantlinkinCSPproductprocess.Laminarcoolingafterthehotrollingreducedthetemperatureoftheplate,andthemoreimportantthingisthattheaustenitewaostlydeposedinthiscourse.Accordingtothecoolingsystem,theaustenitecanbechangedintodifferentanization,andmayhedifferentsizeofcrystallinegrain.Sowecancontroltheanizationformandsizeofcrystallinegrainofthefinishedproductbythecontrolledcooling,andgetbetterprehensiveproperties.

BasedonthelaminarcoolinglineoftheCSPplantofBaotouIron&,SteelGroupCompany,theheattranerconditionswasprehensivelyanalyzed.Betweenthefinemillandthedowncoiler,thecoolingcoursewasdividedintoaircoolingandwatercooling.Accordingtotheactualheattranercondition,thewatercoolingcoursewasdividedintoimpingementregionandparallelflowregion.Finally,thecoefficientsexperienceformulawasget.Anditwasusedinthetemperaturefieldnumericalsimulatecalculationasboundaryconditions.

Duringthecalculation,thelatentheatwasdealtwithspecificheatcapacitylaw.Exceptthematerialdensity,theotherthermalphysicalparametersweredealtasthefunctionoftheplatetemperature.

Theresultofthenumericalsimulatecalculationshows:Thelatentheatreleasedduringthelaminarcoolingmakethecoilingtemperatureincreasedobviously,Ifthethicknessoftheplateenhanced,thetemperaturefieldturnedtomoreuneven,Highertransportspeedwillmakethecoilingtemperatureincreased.Theprimaryreasonofitisreducedthecoolingtime.Increasethespraywaterdensityordecreasethetemperatureofcoolingwaterwillraisetheheattranercoefficients.Asaresultthecoilingtemperaturewasdescended.Bycontrast,thechangeofwatertemperaturehaoreviolentinfluenceontheheattranercoefficients.

Keywords:CSPlaminarcoolingtemperaturefieldnumericalsimulation

论文题目:多流低频电磁铸造铝合金理论及实验研究

TheoreticalandExperimentalStudyoftheMulti-strand

Low-frequencyElectromagicCastingofAluminumAlloy

研究生姓名:谢麒麟

导师姓名:麻永林教授

协助导师:李建超讲师

专业:材料加工工程

摘 要:

低频电磁铸造(CREM)是铝合金成型的一种新兴工艺,它能显着提高铝合金铸锭的性能和质量.本文首先研究了直接冷却半连续铸造过程的温度场,并在此基础上对多流低频电磁铸造各铸流磁场之间的相互影响进行了数值模拟.

通过在铸锭中埋入热电偶,测定了直接冷却半连续铸造过程中Ф100mm的铝合金铸锭近表面的动态温度,采用逆向法计算出了其水冷段的换热系数,该水冷换热系数是铸锭表面温度的函数.开始时随着铸锭表面温