简介:Sm_(0.9)Pr_(0.1)Fe_xandSm_(1-x)Nd_xFe_(1.9)的结构,磁化,和磁伸缩变瘦电影用X光检查衍射,颤动的样品磁强计,和光伸臂方法被调查了。Sm_(0.9)Pr_(0.1)Fe_xthin电影的结构由一张Sm-Pr-Fe无定形相组成,这被发现什么时候x≤2.69并且Sm_(1-x)Nd_xFe_(1.9)的薄电影由一张Sm-Nd-Fe无定形相组成。有Fe内容的增加的在里面飞机磁化ofSm_(0.9)Pr_(0.1)Fe_x薄电影增加,和茶碱飞机coercivity的低价值发生在1.62≤x≤的范围2.28。当时,有增加Fe的磁伸缩价值ofSm_(0.9)Pr_(0.1)Fe_x薄电影增加满足x≤1.94并且减少什么时候x>1.94。Sm_(1-x)Nd_xFe_(1.9)的在里面飞机磁伸缩在低磁场下面的薄电影被Nd的替换为Sm改进了什么时候x=0.2。
简介:阶段和磁电机在合金R(Co_(1-x)Sn_x)的热量的效果有x=的_20,0.025,0.050,0.075,和0.100被X光检查衍射分析和磁化测量调查。在RCo_2的Sn的替换是有限的。为RCo_2的合金的立方的MgCu_2-typestructure被X光检查粉末衍射证实,留下的合金主要由RCo_2阶段组成了,与一些RCo_3和R_5Sn_3杂质阶段一起。Theimpurity阶段随Sn内容的增加增加。合金的T_c不对为Dy(Co_(1-x)Sn_x)的Sn替换很敏感_2和Tb(Co_(1-x)Sn_x)_2inGd(Co_(1-x)Sn_x)_2,居里温度显著地增加。最大的磁性的熵在合金Dy(Co_(1-x)Sn_x)改变_2(x=0,0.025,0.050,0.075)是5.78,5.43,3.88,并且2.98J·kg~(-1)·K~(-1),分别地,并且那些在Tb(Co_(1-x)Sn_x)_2(x=0,0.025)是3.44,and2.29J·kg~(-1)·K~(-1)分别地0-2.0T在应用的地里变化。
简介:InordertoobtainultrafineNd-Fe-Bpowder,aspray-driedprecursorwastreatedbyreduction-diffusion(R/D)process.And,unliketheconventionalR/Dprocess,calciumreductionthatisacrucialstepfortheformationofNd2Fe14BwasperformedwithoutconglomeratingtheprecursorwithCapowder.Byadoptingthismodifiedprocess,itispossibletosynthesizethehardmagneticNd2Fe14Batthereactiontemperatureaslowas850℃.TheaveragesizeofNd2Fe14Bparticlesthatareuniformlydistributedintheoptimallytreatedpowderwas<<1μm.MostNd2Fe14BparticleswereenclosedwiththinlayersofNd-richphase.TypicalmagneticpropertiesofsuchpowderwithouteliminatingimpurityCaOwereiHc=~5.9kOe,Br=~5.5kG,and(BH)max=~6MGOe.
简介:Widegapbrazing(WGB)experimentsusingthebuttedspecimenwitha1.5mmgapwerecarriedoutfortherepairofthefailedK418Bsuperalloylow-pressureturbinevanes.Thehightemperaturecreeprupturestrengthsofthebrazedjointsweretested,andthemicrostructuresandfracturesurfacesofthejointswereobserved.TheresultsshowthatthemicrostructureofK418Balloyjointiscomposedofdenseequiaxedgrain,smallanddiscretecompoundswithafewmicro-pores.Duringthecreeprupturetest,thecracksinitiatepreferentiallyatthemicro-poreorthegrainboundary,thenpropagatealongthegrainboundarytillthefracturehappens.Thecreeprupturestrengthat700℃ofthebrazedjointswith50%brazemetalintheworkingpartcouldexceed90%thatoftheK418Bsuperalloy,andthejointswith100%brazemetalintheworkingpartachieve70%to80%ofthecreeprupturestrengthsfortheK418Bbasemetal.
简介:Inthepresentstudy,artificialneuralnetwork(ANN)approachwasusedtopredictthestress–straincurveofnearbetatitaniumalloyasafunctionofvolumefractionsofaandb.Thisapproachistodevelopthebestpossiblecombinationorneuralnetwork(NN)topredictthestress–straincurve.Inordertoachievethis,threedifferentNNarchitectures(feed-forwardback-propagationnetwork,cascade-forwardback-propagationnetwork,andlayerrecurrentnetwork),threedifferenttransferfunctions(purelin,Log-Sigmoid,andTan-Sigmoid),numberofhiddenlayers(1and2),numberofneuronsinthehiddenlayer(s),anddifferenttrainingalgorithmswereemployed.ANNtrainingmodules,theloadintermsofstrain,andvolumefractionofaaretheinputsandthestressasanoutput.ANNsystemwastrainedusingthepreparedtrainingset(a,16%a,40%a,andbstress–straincurves).Aftertrainingprocess,testdatawereusedtochecksystemaccuracy.Itisobservedthatfeed-forwardback-propagationnetworkisthefastest,andLog-Sigmoidtransferfunctionisgivingthebestresults.Finally,layerrecurrentNNwithasinglehiddenlayerconsistsof11neurons,andLog-Sigmoidtransferfunctionusingtrainlmastrainingalgorithmisgivinggoodresult,andaveragerelativeerroris1.27±1.45%.Intwohiddenlayers,layerrecurrentNNconsistsof7neuronsineachhiddenlayerwithtrainrpasthetrainingalgorithmhavingthetransferfunctionofLogSigmoidwhichgivesbetterresults.Asaresult,theNNisfoundedsuccessfulforthepredictionofstress–straincurveofnearbtitaniumalloy.
简介:TheCurietemperatureof(Nd1-xPrx)2Fe14CoyBcompounds(x=0,0.2,…,1.0andy=O,2,4,6,14)hasbeendeterminedwithACinitialsusceptibilitymeasurement.ItwasfoundthatthevariationsofCurietempera-turewithxisnotlinearfory=0and14,whereasitislinearforothervaluesofy.Thelatticeconstantsof(Nd1-xPrx)2Fet14BweredeterminedbyusingX-raydiffraction.Thelatticeexpansionwasmostlyalongthecaxis,whereasthatalongthea-axisremainedpracticallyzeroforthewholeseries.ItissuggestedthatPratomsmayshowsitepreferenceinR2M14Bcompounds(M=FeorCo).DuetothesubstitutionofCoforFe.thetendencyofsitepreferenceofPrbecomeslesspronounced,whichmaybeattributedtothedecreaseofdiffer-enceofcrystalelectricfield(CEF)actingonthetworareearthsiteswiththeintroductionofCoorFe.Incon-trasttothatofthePratoms,thesitepreferenceofCoiu(Nd(1-x)Prx)2Fe(14-y)CoyBcompoundsdoesnotdependonthecompositionoftherareearthsublattice(R=NdorPr).
简介:采用B50A789材料制备的压气机叶片产生的缺陷,主要是由于原材料内部夹杂、局部偏析、组织粗大,带状偏析和折叠引起的.本研究采用金相和能谱分析方法研究了锻造压气机叶片表面裂纹的形成机理,并对其锻造裂纹的形成过程进行有限元模拟.结果表明结合低倍及高倍形貌特征,可以得出叶片缺陷为锻造加工过程产生的折叠裂纹;通过有限元模拟分析认为锻造叶片表面裂纹是源于锻件在制坯过程中,在连接杆与安装圆盘的转接处形成啃伤台阶,导致终锻结束时在叶身形成折叠裂纹缺陷.同时通过对试验过程中锻造工艺调整,采用分料卡子对过渡区分料或进行打磨来保证转角半径圆滑过渡,可有效避免叶片表面折叠和裂纹缺陷的形成.
简介:有软磁性的层(Fe)或antiferromagnetic层(Mn,FeMn或MnO)的各向异性的Pr-Fe-B电影被准备由直流(DC)磁控管在Si(100)底层上劈啪作响在650点加热了?te是由有90的一个方向的热伪造?%塑料变丑。然后,前进状态的微观结构合成被观察,并且机械性质的变化法律和磨擦表演在以后并且在塑料使变形前被比较。结果显示艾尔3增强Zr的粒子旋转并且闯入10-20的更小的尺寸?ng可溶的biopolymer有三个转变金属离子的牛的浆液白朊(BSA)(M,M=Cu,公司,Mn)。白朊一定的金属离子的有约束力的模式和比率被调查。BSA-M建筑群被紫外力的、圆形的二色性(CD)描绘系列和polyacrylamide胶化电气泳动(页)。当聚合物支架和金属建筑群作为催化活跃中心工作了,BSA服务了。当到BSA的转变金属离子建筑群的有约束力的比率是5:1时,结果证明BSA的结构仍然保持未改变。而且,清除superoxide一??
简介:ExtractingB2O3fromcalcinedboronmud(CBM)wasstudied.TheeffectoffactorssuchasreactiontemperatureandNaOH-to-CBMmassratioonB2O3extractionefficiencywasinvestigated.TheresultsshowthatincreasingreactiontemperatureandNaOH-to-CBMmassratioincreasesB2O3extractionefficiency.TherearetwostagesfortheB2O3extractingprocess:0–20ministhefirststage,whichisrapid;20–50ministhesecondstage,whichisslowerthanthefirststage.Theoverallextractingprocessfollowstheshrinkingcoremodel,andthefirstandsecondstagesaredeterminedtoobeythesurfacechemicalreactionmodelandthediffusionthroughtheproductslayermodel,respectively.Theactivationenergiesofthefirstandsecondstagesarecalculatedtobe41.74and15.43kJ·mol-1,respectively.TheB2O3extractingkineticsequationsofthefirstandsecondstagesarealsoobtained.