3d x-ray diffraction microscopy larry margulies. 200 µm metal structures heat defor- mation 200 µm...
TRANSCRIPT
200 µm
Metal Structures
HeatDefor-mation
200 µm5 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 100-1000 structural units• In-situ annealing and deformation
studies(4D)
3DXRD set-up
Area detector
Detector IL = 5-10 mmPosition and Orientation
Detector IIL = 40 cmOrientation and Strain
Acq. time: 1-10 sec 10-100 msec
Two step process
Up to 1000’s grains:
CMS position volume: 1-10% average orientation: 0.2 deg average elastic strain: =10-4
1. Indexing:
GRAINSPOTTERIMAGED11
2. Reconstruction
GRAINSWEEPER
Growth curvesFarfield detector only: Growth curves:
0 20 40 60 800
10
20
30
40
50
Nucleation time [min]
Fre
que
ncy
[%]
All orientations
0 20 40 60 800
10
20
30
40
50
Nucleation time [min]
Fre
que
ncy
[%]
Cube orientation
0 20 40 60 800
10
20
30
40
50
Nucleation time [min]
Fre
que
ncy
[%]
Rolling orientations
0 20 40 60 800
10
20
30
40
50
Nucleation time [min]
Fre
que
ncy
[%]
Other orientations
0 2 4 6
x 10-3
0
5
10
15
20
25
Growth rate [m/s]
Fre
que
ncy
[%]
All orientations
0 2 4 6
x 10-3
0
5
10
15
20
25
Growth rate [m/s]
Fre
que
ncy
[%]
Cube orientation
0 2 4 6
x 10-3
0
5
10
15
20
25
Growth rate [m/s]
Fre
que
ncy
[%]
Rolling orientations
0 2 4 6
x 10-3
0
5
10
15
20
25
Growth rate [m/s]
Fre
que
ncy
[%]
Other orientations
244 grains
StatisticsNew Avrami-type model
0 1 2 log (time)
log(
-ln(
1-V
V))
a
b600 650 700 750 800 850 900
0.0
0.2
0.4
0.6
0.8
1.0 Measurement
CNT
(dN
/dt)
/(d
N/d
t) ma
x
T (oC)
0
20
40
60
80
100
Nto
tal
Pearlite – Ferrite – Austenite
0
10
20
30
R (
m)
600 700 800 900
T (oC)
600 700 8000
10
20
Growth curves
dN/dt
Phase Transformations in Carbon Steel
N
Activation energy off by 100!
100 110
111
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(C2O2H3)2.H2O.
70 grains of size < 1 micron Cell ~1400 Å3 (C2/c)
Result: Single crystal quality refinement!
Applications to:• Pharmacy• Photochemistry• Protein Crystallography
Grain Mapping
Area detector
Detector IL = 5-10 mmPosition and Orientation
Detector IIL = 40 cmOrientation and Strain
Video of growthof 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:Ce25µm
YAG150µm
CCD
Structured Scintillator
Principle: Electrochemical etch:@ 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 3DXRDfaster 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 Instrumentation3DXRD InstrumentationOptics (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