3D X-Ray Diffraction Microscopy Larry Margulies
200 µm Metal Structures Heat Defor- mation 200 µm 5 µm Challenges: - Multiple lengthscales - Heterogeneities - Predicting the dynamics 4D (space + time) Traditional Microscopy is 2D
3DXRD Vision 3D characterization of individual grains within bulk polycrystals –Volume –Crystallographic orientation (intragranular ODF) –Grain boundary morphology (3D mapping) –Elastic strain tensor –Structural refinement Statistics over structural units In-situ annealing and deformation studies(4D)
3DXRD set-up Area detector Detector I L = 5-10 mm Position and Orientation Detector II L = 40 cm Orientation and Strain Acq. time: 1-10 sec msec
Two step process Up to 1000’s grains: CMS position volume: 1-10% average orientation: 0.2 deg average elastic strain: = Indexing: GRAINSPOTTER IMAGED11 2. Reconstruction GRAINSWEEPER
Growth curves Farfield detector only:Growth curves: 244 grains Statistics New Avrami-type model log (time) log(-ln(1-V V ))
g a g a q a b Pearlite – Ferrite – Austenite Growth curves dN/dt Phase Transformations in Carbon Steel N Activation energy off by 100!
Grain rotation for 95 grains in Al, 100 m grains, 5 mm thick Tensile strain: 6 % Grain rotation
Third route in Crystallography Single Crystal Powder X-ray data: Multicrystal
Third route in Crystallography Validation: Cu(C 2 O 2 H 3 ) 2. H 2 O. 70 grains of size < 1 micron Cell ~1400 Å 3 (C2/c) Result: Single crystal quality refinement! Applications to: Pharmacy Photochemistry Protein Crystallography
Grain Mapping Area detector Detector I L = 5-10 mm Position and Orientation Detector II L = 40 cm Orientation and Strain
Video of growth of an internal grain Recrystallization of 42% deformed pure Al during annealing at ~200 C.
Grain growth Sample: Al(0.1% Mg) Initial 800 min anneal at 450 C 491 grains 49 grains
Present detector Resolution: ~3µm Efficiency: ~1% Long tails in PSF Sample YAG:Ce 25µm YAG 150µm CCD
Structured Scintillator Principle:Electrochemical KTH, Sweden
LuAG 25µm SS 4µm pitch Tomographic images of Al with W particles taken with a conventional LuAG 25µm thick screen and a structured scintillator with a 4µm pitch
3D high resolution detector –mapping of deformed microstructures –“box beam” mapping Faster throughput for in-situ mapping 100 nm resolution 2D(3D) detector –R&D is needed for a solid state device Future of 3DXRD faster and smaller
Acknowledgments Risø: H.F. Poulsen, C. Gundlach, D. Juul Jensen, E. Knudsen, E.M. Lauridsen,W. Pantleon, S. Schmidt, H.O. Sørensen, G. Winther ESRF, ID11: A. Goetz, Å. Kvick, G. Vaughan, J. Wright
3DXRD Instrumentation Optics (brown): WB: White beam LC: Bent Laue crystal WBS: White beam stop ML: Bent multi layer MB: 2 dimensionally micro focussed monochromatic beam BS: Monochromatic beam stop Sample environment (yellow): I: Cryostat II: Furnace III: 24kN Stress rig Detectors / slits (purple): 1: Large area detector 2: Conical slit system 3: High resolution area detector 4: Optional detector system 5: Small area detector