Max-Planck-Institut für Eisenforschung GmbH 3D orientation microscopy based 3D orientation microscopy based on FIB-EBSD tomography: P t Potentials and limits. ti l d li it S. Zaefferer
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy Contents • The need and methods for 3D characterization of crystalline matter • Principle of 3D characterisation by FIB-EBSD p y tomography • Application example: Application example – Coupling of 3D measurements with 3D modelling • Material restrictions: • Material restrictions: – beam induced material changes • Conclusions C l i 2
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy Contents • The need and methods for 3D characterization of crystalline matter • Principle of 3D characterisation by FIB-EBSD p y tomography • Application examples Application examples – Grain boundary characterization – Accurate observation of deformation structures Accurate observation of deformation structures – Microstructure characterization for 3D modelling • Material restrictions: • Material restrictions: – beam induced material changes • Conclusions C l i 3
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy The need for 3D observations P Pre-condition: crystallographic information must be accessible di i ll hi i f i b ibl to investigate the microstructure of crystalline matter 2D Stereology 3D Destructive 3D Non-destructive statistical observations: static observations: process observations: • grain size distribution • comprehensive • recrystallization • grain shape (from 2 morphology information (e.g. nucleation, grain sample sections) l i ) • 3D connectivity of 3D i i f growth) • volume fraction and features • deformation (e.g. distribution of 2nd distribution of 2nd • grain boundaries • grain boundaries texture formation) t t f ti ) phase constituents • input data for modelling • phase transformation • texture-microstruc- texture microstruc • 3D deformation 3D deformation (e g variant selection) (e.g. variant selection) ture relations structures Many problems can be solved by 2D statistical observations but for some 3D observations are essential 4
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy Serial sectioning methods S Sectioning: ti i • mechanical or chemical polishing • FIB milling • FIB milling…. Observation: Problems: Problems: • BSE-Microscopy, EBSD, optical BSE Mi EBSD i l • depth definition microscopy…. • contrast definition contrast def n t on for segmentation • very laborious y M.V. Kral & G. Spanos, Acta p Mater. 47 (1999), 711 serial sectioning and reconstruction of reconstruction of allotriomorphic cementite by mechanical polishing 5
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy Advantages of FIB-EBSD tomography • Sectioning by FIB – accurate depth definition – flat and parallel sections (< 1° deviation ) – high resolution (< 50 nm) • Observation by EBSD – well-defined contrast on crystalline material well defined contrast on crystalline material – ideal for reconstruction of grains in 2D and 3D – quantitative description of microstructure quantitative description of microstructure – high resolution (~ 50 nm) • Combination of FIB and EBSD • Combination of FIB and EBSD – table-top instrument Recent reviews: • Uchic et al., MRS Bulletin 32 – “high” measurement speed high measurement speed ( 00 ) 40 (2007) 408-416 416 • Zaefferer et al., Met. Mater. – fully automatic Trans. 39A, (2008) 374-389 6
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy Length scale of tomographic measurements Midgley & Weyland Midgley & Weyland Ultramicroscopy 96 (2003) Zaefferer, Wright & Raabe Mat. Trans. A (2008) and Mulders & Day Mat Sci Forum 495-497 (2005) B.C. Larson et al., B C Larson et al crystals Nature 415 (2002) 887 nano M.V. Kral, G. Spanos, Acta Mater. 47 (1999) 711 H.F. Poulsen et al., J. Appl. Cryst. 34 (2001) 751 macroscopic texture fields 7
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy Contents • The need and methods for 3D characterization of crystalline matter • Principle of 3D characterisation by FIB-EBSD p y tomography • Application examples Application examples – Grain boundary characterization – Accurate observation of deformation structures Accurate observation of deformation structures – Microstructure characterization for 3D modelling • Material restrictions: • Material restrictions: – beam induced material changes • Conclusions C l i 8
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy Instrument overview • Scanning electron microscope (SEM) – observation of microstructure • Scanning Ga + -ion G microscope (FIB = focused ion beam) (FIB = focused ion beam) – sputtering of material for EBSD system: TSL with serial sectioning Hikari camera • Quantitative images with EBSD and EDX EBSD and EDX – quantitative SEM & FIB: characterisation of Zeiss Crossbeam 1540 microstructure i t t 9
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy Principle of serial sectioning & orientation microscopy ion milling ion milling electron alignment marker beam SEM objective lens lens tilt 34 ° e - e Ga + to EBSD detector sample in cutting position EBSD e - (36° tilt) (36 tilt) camera sample in EBSD position (70° tilt) “tilt set-up” Zaefferer, Wright, Raabe, Mat. Trans. A (2008) 5 µm 10
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy Geometrical set-up alternatives for FIB-EBSD SEM 54° 54 FIB cross- over point 36° EBSD EBSD EBSD sample 70° 70° tilt set-up static set-up rotation set-up +/- medium tilt positioning + no stage movement + high stage positioning accuracy accuracy required required accuracy accuracy + tilt inaccuracies create + highest possible +/- rotation inaccuracies linear distortions positioning accuracy create shear distortions + simple software simple software + unconventional but non- unconventional but non +/- software correction / software correction correction possible problematic EBSD set-up more complex + freely selectable milling + high measurement speed +/- every milling position p position requires a different q ff holder Zaefferer et al., Met. Mater. Mulders, Day, Mat. Sci. Forum Trans. 39A, 374-389 (2008) 495-497, 237-242 (2005) 11
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy EBSD & FIB-sliceing: 3D microstructure of pearlite Y X X Z 20 µm 30 µm 12
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy Contents • The need and methods for 3D characterization of crystalline matter • Principle of 3D characterisation by FIB-EBSD p y tomography • Application examples Application examples – Grain boundary characterization – Accurate observation of deformation structures Accurate observation of deformation structures – Microstructure characterization for 3D modelling • Material restrictions: • Material restrictions: – beam induced material changes • Conclusions C l i 13
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy The cube texture in Fe 36% Ni cold rolled material: recrystallized material: Cu-type rolling texture yp g sharp cube texture p • Origin of the cube texture: oriented nucleation • Possible reasons for texture selection: Possible reasons for texture selection: – stored energy differences (Etter et al. Scripta Mat. 46 (2002) 311) – grain boundary properties (e g 40° <111>) (“micro- grain boundary properties (e.g. 40 <111>) ( micro oriented growth”, (Duggan et al., Acta metall. mater. 41 (1993) 1921) ) – differences in mobility of dislocations in different ff r nc s n mo ty of s ocat ons n ff r nt orientations (differences in recovery rate) (Rhida & Hutchinson, Acta metall 30 (1982) 1929) 14
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy 3D-orientation microscopy on cold rolled material Orientation map KAM map RD ND RD ND non cube grain TD TD cube grain 20 µm 20 µm 20 µm 20 µm Cube grains have low internal orientation fluctuations Cube grains have low internal orientation fluctuations. Some other orientations do have that as well. 15
Max-Planck-Institute for Iron Research, Düsseldorf S. Zaefferer: 3D orientation microscopy Microstructure after 1 min annealing possibility to reconstruct original neighbourhood of grown neighbourhood of grown grains original cube band grown cube cube nucleus • only small cube-grain areas with 40°<111> orientation relation • original neighbourhood of grown • original neighbourhood of grown grain does not show any special boundaries with cube band 16
Recommend
More recommend
