高角度环形暗场Z衬度像成像原理及方法

ZX(010062):,,,(HAADF)(Z-):Z;;:TN153:A:1004)244X(2002)04)0044)04,,,,,0.1nm[1]:1.(1MeV);2.(Cs);3.;4.;5.(HRTEM);6.Z(HAADF)Z,,1STEM的成像1.1STEM,(TEM),,;(SEM),,,(STEM)TEMSEM(100~400keV)(0.126nm)[2],TEMSEMSTEM11/keVTEM100SEM1~30STEM100~400STEM(HB-501),SEMTEM,STEMSEMTEM/STEM,(S)TEMTEM8STEM,TEMSEMJEOL2010F1.2STEMTEM1TEMSTEM1(A)TEM第25卷第4期2002年7月兵器材料科学与工程ORDNANCEMATERIALSCIENCEANDENGINEERINGVol.25No.4July2002X:2002-03-18;:2002-05-10:(1954-),,,,,E-mail:[e-mail],,,(),,,,,,,,(HRTEM),1(B)STEM,[4],,,,AP,BBP,A[5]STEM,(A)(B)(C)1(A)TEM(B)STEM(C)STEM,,,,,STEMTEM,STEMTEMSTEMTEM,,,STEMTEMSTEM,,STEM,TEM,STEM,TEMSTEM,STEMTEM1.3STEM1970,Crewe[6],STEM,Z,Crewe,,Z32,Z[7],Pennycook,()YBa2Cu3O7-XErBa2Cu3O7-XZ[8]Penny2cookCrewe,Z32,,,,Rutherford(Z2),2高角度环形暗场(HAADF)方法TEM,454:Z,,,,,(STEM),STEM,,,(HighAngleAnnularDarkField),HAADFZ2(HAADF)[9](Pennycook),,H1H2R(Rutherford):RH1,H2=(mm0)Z2K44P3A20(1H21+H20-1H22+H20)m);m0)Z)K)A0)H0),t,NIs=RNtI,HAADF,,Z,ZSTEM,,,,,,3GaAsHAADFZ[10]GaAs,,Ga(Z=31)As(Z=33),GaAsSEM,,G2(HAADF)3GaAsHAADFZ,G,5keV,G,[7]:G=-0.0254+0.016Z-0.000186Z2Z,GZ,,,HAADF,,Rutherford,Rutherford,,,(),[11],,,0.14625nmHAADFZTEM,JEOLJEM2010F,0.5mmTEM0.19nm,HAADF0.125nm(HAADFZ)3结语70,,,,(CBED)(EELS)(HRTEM)(ED)HAADFZ,HAADFZ(),:,:[1]DyckDVan.Thefutureofhighresolutionelectronmi2croscopy[J].,2000,19(5):670.[2]YanY,PennycookSJ.Z-contrastimagingdecagonalquasicrystals:Anatomisticmodelofgrowth[J].MaterialsScienceandEngineering,2000,294-296:211-216.[3],,.[A].:,1989.478.[4]JoyDC,RomingAD,GoldsteinJI.Principlesofanalyti2calelectronmicroscopy[A].NewYork:PlenumPress,1986.343.[5],.[A].:,1987.20.[6]CreweAV,Wallj,LangmoreJ.Visibilityofsingleatoms[J].Science,1970,168:1338.[7][]E.[A]..:,1998.135-146,212.[8]PennycookSJ,BoatnerLA.Chemicallysensitivestruc2ture-imagingwithascanningtransmissionelectronmi2croscopy[J].Nature,1988,336:565.[9][],.[A]..:,2002.149.[10]PennycookSJ,DickeyEC,etal.Acombinedeperimen2talandtheoreticalapproachtoatomicstructureandsegre2gationatceramicinterfaces[J].JournaloftheCeramicSociety,1999,19:2212.[11]ZhangXiao-Feng,ZhangZe.Progresstransmissionelectronmicrocopy[A].Beijing:TsinghuaUniversityPress,1999.30.ImagingprincipleandmethodofHAADFZ-contrastimageLIPeng-fei(SchoolofMaterialsScienceandEngineering,InnerMongoliaPolytechnicUniversity,Huhehot010062,PRC)Abstract:Conventionalhigh-resolutionelectronmicroscopyusesthephase-contrastmethodtoimage,inwhichthediffractedbeamsemergingfromthesamplearerecombinedonthescreenofthemicroscope.Theresultantcontrastde2pendsontherelativephasesofthediffractedbeams.Byusingahighangleannulardetectorinascanningtransmissionelectronmicroscope,highatomic-numbercontrastimagemaybeobtained.Thisarticlesummarizestheimagingprincipleandmethodoftheatomic-numbercontrastimage(Z-contrastimage)usinghighangleannulardarkfield(HAADF)technique.Keywords:Z-contrast;HAADF;imagingprinciple(43)strengthesdecreasewiththeriseoftemperature.Theirplasticitieschangelittlefromroomtemperatureto500e,butin2creasesrapidlywiththeriseoftemperatureabove500e.Atabout700e,therateofincreaseoflowcarbonU-Tialloys.plasticityslowsandhighcarbonU-Tialloys.plasticitydecreasesclearly.ThereasonisthattheB-phaseisproducedinthealloysat700e.Furthermore,muchimpuritiesofTiCinhighcarbonU-Tialloysmakethestrengthofgrainbound2ariesdrop.Keywords:U-Tialloy;tensileproperty;temperature474:Z