Time-resolved 3D measurements ofmechanical behaviours in aluminium alloys
Presented by Hiroyuki TODA （戸田裕之）1,with the collaborations of D. Leclere1, L. Qian1,H. Oogo1, Z.A.B. Shamsdin1, Y. Suzuki2, A. Takeuchi2,
K. Uesugi2 and M. Kobayashi1
1. Toyohashi University of Tech.,Toyohashi, Japan
2. Japan Synchrotron Radiation Research Institute Current
statusofsynchrotron
microtomography
 Various advanced 3D/4D image analyses
I. Microstructural tracking for strain mapping
II. Grain Boundary Tracking (GBT)III. Diffraction-Amalgamated GBT (DAGT) techniquefor crystallographic analysis
 Examples of applications
I. Analyses of a cracked-medium
II. Ductile fracture: hydrogen pore mechanism
III. High temperature cavitation from hydrogenpores From observation / analyses to mater. development:“Reverse 4D Materials Engineering” (R4ME)
 Summary2

X-ray microtomography (CT): Imaging to appl.

Courtesy of Mr. Taki in Nihon Visual Science, Inc.

Current status of various X-ray CT apparatuses

http://www.shimadzu.co.jp/ndi/pr
oducts/x_ryct/x_ryct04.html

http://www.bio-imaging. com/indsystems.asphttp://www.med.shimadzu.co.jp/
clinic/std/ct/index.html

http://www.spring8.or.jp/ja/

Labo CT

Synchrotron(µ-focus)
Radiation (SR)-CTResol’n
1 nm

10 nm

Precipitate
GB

1 µm

10 µm

MicroporeCrack

100 nmMicrocrack

IMCp(High E)

100 µmMedical CT
1 mm

Macro-defects

Inclusionµ-structural features of materials

4SR-CT application to a cracked metals(voxel size in µm3)

6.42003 (Toda@ESRF)
0.7
2004 (Toda, Uesugi@SPring-8) 0.47
2006 (Toda, Takeuchi@SPring-8)0.048
1999 (Stock@Cornell HESS)

Fatigue crack (White)Stock, et al., Phil. Trans. R. Soc.
Lond. A, 357(1999), 2755

50 µm

Fatigue crack (Black): Crack opening ~ a few micron
Toda, Sinclair, et al., Phil. Mag. A, 83(2003), 2429.

Good visualisation of a crack and its opening behaviour
µ-structural features visible owing to the high resolution5

SR facilities

Electrons

X-ray

Synchrotron radiation
http://www.spring8.or.jp/e/6

 Current status of synchrotron microtomography
 Various advanced 3D/4D image-analyses
I. Microstructural tracking for strainmapping
II. Grain Boundary Tracking (GBT)III. Diffraction-Amalgamated GBT (DAGT) techniquefor crystallographic analysis
 Examples of applications
I. Analyses of a cracked-medium
II. Ductile fracture: hydrogen pore mechanism
III. High temperature cavitation from hydrogenpores From observation / analyses to mater. development:“Reverse 4D Materials Engineering” (R4ME)
 Summary7

3D/4D image analysis techniques developed 8100µmImaging

Crack growth

Damage4D imaging

3D imaging

Crack driving force mapping
4D ε mapping

Quantification

Elementalmapping Some of these hadn’t been accessible experimentally

3D image-based
Grain tracking Crystallographic orientation
simulation

Microstructural Tracking Technique
Number of particles/poresin practical Alinalloys
Numbersof particles/pores
Al(1/mm3)

Materials
Pure Al (99.999%)
Pure Al (A1050)
Al-Cu-Mg alloy (A2024)

Segmentation, labelingRegistration
MatchingSpecies
Numbermicro-pores
3,036
micro-pores
10,375
particles
150,185
micro-pores
63,111
Al-Mg alloy (A5XXX)
micro-pores
20,160Al-Mg-Si alloy (A6061)
micro-pores
21,184Al-Zn-Mg-Cu alloy (A7075) micro-pores
28,852

 A huge number of µ-structuralfeatures observable

Tracking

3D Mapping:
ε , d, σ, CDF…

 Physical displacement of each particle/pore tracked
 Unique experimental technique to obtain 3D/4D mapping of9mechanical quantities
Kobayashi, Toda, et al., Acta Mater., 56(2008), 2167

Details of microstructural tracking
PAS

C
B

DE

nth. image

RQT(n+1)th. image

Matching Parameter, Mp
NoMp ≥ Mpth1

Matching parameter, Mp
M p = α × M L + β × M V + γ × MS

ML: Parameter for location, MV: Parameter for volume
MS: Parameter for surface areaα, β, γ : Parameter's weight (α +β +γ = 1)

Spring model (SPM)

N1 sp b′i − b i
Esp =∑
N sp i =1 b i

YesYes∆Mp ≥ Mpth2

Nsp: number of springsb and b': spring vectors

NoPended marker

Trajectory prediction

SPM
MatchedMatchedmarkers

Total energy ofimaginary spring, Esp

No

Rejected
markers

Mpth1, Mpth2: Threshold value for tracking-Data extrapolation bypolynomial approximation-Physical theories utilized
if it is appropriate

Kobayashi, Toda, et al., Acta Mater., 56(2008), 2167

10 Current status of synchrotron microtomography
 Various advanced 3D/4D image-analyses
I. Microstructural tracking for strain mapping
II. Grain Boundary Tracking (GBT)III. Diffraction-Amalgamated GBT (DAGT) techniquefor crystallographic analysis
 Examples of applications
I. Analyses of a cracked-medium
II. Ductile fracture: hydrogen pore mechanism
III. High temperature cavitation from hydrogenpores From observation / analyses to mater. development:“Reverse 4D Materials Engineering” (R4ME)
 Summary11

Another key tech. for GBT: GB visualisation
Immersing TP in liquidus metal
Diffusion into GB.
*Diffusion length：x = (2Dt)1/2(T = 323K，t = 500s)
Grain interior,x = 2.51×10−5 µm
Grain boundary,x = 79.5 µm
Observation (absorption contrast)*Transmitted intensity：
I = I0 exp{-(mM tM+mGa tGa)}
Pairs of metals that cause LME

Crack

100µm

Ga charged GB
AlEmbrittling liquids
MaterialAl
Hg, Ga, In, Sn, Pb, Cd, Zn, Na
CrackCu
Hg, In, Ga, Bi, Zn, Li, Sn, Pb
Ti
Hg, Cd, Ag
GBMg Na, K, Rb, Cs, Zn
Khor, et al. J. of Physics: Condensed Matter,Fe
Hg, In, Li, Sn, Pb, Cd, Zn, Cu vol.16, 2004, S3511-S3515.
12

Grain Boundary Tracking (GBT) technique•••Al-Cu alloy

Load 1

Load 2

4D obs. during deformation Final load
Reverse tracking of particles

Particles areclassified into…
GB particles•••Load 1

Load 2

Final load
(GB image)Morphologicalinformation

Final load•••

σ /ε mappingin each grain

Particles ingrain interior
13 Current status of synchrotron microtomography
 Various advanced 3D/4D image-analyses
I. Microstructural tracking for strain mapping
II. Grain Boundary Tracking (GBT)III.Diffraction-Amalgamated GBT (DAGT)
technique for crystallographic analysis
 Examples of applications
I. Analyses of a cracked-medium
II. Ductile fracture: hydrogen pore mechanism
III. High temperature cavitation from hydrogenpores From observation / analyses to mater. development:“Reverse 4D Materials Engineering” (R4ME)
 Summary14

XRD using an X-ray pencil beam for DAGTThe experiment was
carried out at SPring-8
synchrotron
facility(Hyogo, Japan) with thefollowing parameter

SamplerotationzyA grain of interest (Red)
Schematic demonstrating theexperimental setup and how thebeam
interactswithanindividual grain.

Beam line: BL20XU
Energy: 35 keV
Camera: 2000x2000 CMOS
Sintillator: Gd2O2SiTb
Beam Size: 10 μm x 10 μm
Sample-detector: 13 mmz-step: 16 μm x 20y-step: 10 μm x 60
Rotation: 0°-180°
Exposure: 0.1s / 1°
15

Local strain map on a virtual cross-section
εeq

[%]
25εxx

εyy

[%]
−10[%]−10εzz[%]20γxy[%]
100γyz0−1030µm[%]
10γzx[%]
1000−10−10Tensile direction

TD（ｚ）ND（ｙ）

000

 Strain map at macroscopicstrain of 10.6 % Large strain variation in
every single grain, that is
extensively
developed
across grain boundaries
16 Current status of synchrotron microtomography
 Various advanced 3D/4D image-analyses
I. Microstructural tracking for strain mapping
II. Grain Boundary Tracking (GBT)III. Diffraction-Amalgamated GBT (DAGT) techniquefor crystallographic analysis
 Examples of applications
I. Analyses of a cracked-medium
II. Ductile fracture: hydrogen pore mechanism
III. High temperature cavitation from hydrogenpores From observation / analyses to mater. development:“Reverse 4D Materials Engineering” (R4ME)
 Summary
1750403020100µm

Eutectic Al-Si phase(Brittle)

α-Al phase(Ductile)

10

Crack growth direction

Local fracture resistance, CTOD (µm)

Evaluation of local fracture resistance: Crack
growth through a dual-phase material (Al-7Si)

0
Displacement in the width direction

 Premature crack propagation in a brittle eutectic Al-Si phase No substantial crack growth in a ductile α-Al phase
H. Toda, et al., Acta Mater., 56(2008), 6027

18Extensive particle damage distribution
εeq (%)
30

Particle

25Loading direction

201510Damage zone
(Fracture mech.)

Crack

50

Lateral view
TD50µm

100 µmTD

LD Damage observed extensively ahead of the LD
crack tip far beyond the large strain region
assumed in the fracture mechanics. It
Front view
exhibits shear-band-like localization.
(GB visualized)
 Effects of underlying texture obvious
19 Current status of synchrotron microtomography
 Various advanced 3D/4D image-analyses
I. Microstructural tracking for strain mapping
II. Grain Boundary Tracking (GBT)III. Diffraction-Amalgamated GBT (DAGT) techniquefor crystallographic analysis
 Examples of applications
I. Analyses of a cracked-medium
II. Ductile
fracture:hydrogenporemechanism
III. High temperature cavitation from hydrogenpores From observation / analyses to mater. development:“Reverse 4D Materials Engineering” (R4ME)
 Summary20

Long-unrecognized pores in various alloys
99.999 % Al

A1050

A2024

Al-6%Mg

A6061

A7475

50 µm
 High-density micro pores observed even in wrought aluminium
alloys by employing the high-resolution X-ray tomography
21Toda, et al., Acta Mater., 57(2009), 2277

Toda, et al., Philos. Mag.,(2012), under review

True origin of ductile fracture

Nominal stress, σ / MPa Pores caused the final fracture The other pores
 Void from particle damage
 Particles
250
200

1st150

9th

100
50
0

Before loading
020 40 60 80
Nominal strain, ε (%)

Stress-strain curve Pre-existing pores exhibit
premature growth underloading, thereby inducing
ductile fracture Well-known particle frac20 µm ture mechanism operates
3D fracture behavior of a 2024 Alonly incidentally22

Dimple patters originated from H pores
Dimples from pores（Yellow）

40 µm

40 µm

Fracture surface (Unnotched) Fracture surface (Pre-cracked)
Dimple patterns originated from micro pores in the three TPs
Unnotched Notched Pre crack
3.7
4.6
4.2
Avg. diameter (µm) Micro pore
Particle damage 3.3
3.6
3.8
Micro pore
54.6 < 62.3 < 67.1
Areal fraction (%) Particle damage
45.4
37.7
32.9
 Dimples originated from H pores occupy more than 50 %
 Fractional area increases with the increase in stress triaxiality23Properties Current status of synchrotron microtomography
 Various advanced 3D/4D image-analyses
I. Microstructural tracking for strain mapping
II. Grain Boundary Tracking (GBT)III. Diffraction-Amalgamated GBT (DAGT) techniquefor crystallographic analysis
 Examples of applications
I. Analyses of a cracked-medium
II. Ductile fracture: hydrogen pore mechanism
III.High temperature cavitation fromhydrogen pores From observation / analyses to mater. development:“Reverse 4D Materials Engineering” (R4ME)
 Summary24

Effects of H pores on cavitation at high T• In-situ tensionof Al-4.5Mg.
at 773 K at ε of 10-2s-1• Trans-/inter-granulartransition regime

HeaterToda, et al., Acta Mater., under review, (2012)

Amorphous
carbon loadframe

X-raySpecimen (inside)
Rotation stagey zx

ε = 0.28
0.00
0.40
0.51
0.74
0.82
0.85

High temperature test rig Growth of pores/cavities under tention
Origin of the common extensive cavitation during hightemperature deformation investigated as well25

Growth of H pore / creep cavity
108Voids/pores initiated at εapplied= 0.000.28Pre-existinghydrogen pore

0.40
0.51
0.740.82

642100Volume fraction, Vf (%)

Mean diameter, dm/ µm

120.85000.2

0.4

0.60.8

Applies tensile strain, εz

1.0Toda, et al., Acta Mater.,under review, (2012)

Pre-existinghydrogen pore

0.00
0.28

10-1
0.74
0.40
0.51

10-2

0.82
0.85
000.2

0.4

0.60.8

Applied tensile strain, εz

1.0

Change in the diameter of creep Change in the Vf of creep cavity
cavity initiated at each applied εinitiated at each applied ε Growth behaviors are similar between pores and creep cavities
 Pre-existing pores and creep cavities initiated early tend togrow bigger: Pre-existing pores finally account for 64 % in Vf 26

 Current status of synchrotron microtomography
 Various advanced 3D/4D image-analyses
I. Microstructural tracking for strain mapping
II. Grain Boundary Tracking (GBT)III. Diffraction-Amalgamated GBT (DAGT) techniquefor crystallographic analysis
 Examples of applications
I. Analyses of a cracked-medium
II. Ductile fracture: hydrogen pore mechanism
III. High temperature cavitation from hydrogenpores From observation / analyses to mater.
development:“Reverse4DMaterialsEngineering” (R4ME)
 Summary27

5 yr project “A new concept breakthroughin materials development:
Reverse 4D materials engineering”【Research Group】

Toda / Kobayashi Lab(Toyohashi Tech)

Maters Sci and Engng
Recruiting !

Comp Solid Mech
Kuwazuru Lab(Fukui Univ)

Information Tech
Batres Lab(Toyohashi Tech)【Term of Project】 FY2012-2016【Budget Allocation】 2.1 Million dollars【Grant】 Grant-in-Aid for Scientific Research (S) from the Japan
28
Society for the Promotion of Science (JSPS)Reverse 4D Materials Engineering (R4ME)

 The conventional materials development process inevitably
needs trial and error. Averaged properties evaluated aftersampling limited µ-structural features.
 R4ME enables rapid development of high-performance materials
in which µ-structures are virtually optimized by means of IBS
 To render R4ME a practical technique, the representation of agiven complex 3D µ-structure is ‘coarsened’ to make it suitable toconventional materials design techniques
29

Coarsening

Basic conceptµ-structurepProperties
qFeatures to be coarsened:Particles, GB, crystallographic grains,alloying elements…
Cvntl. understanding
Reduction of model dimension*Evaluation with arbitrarily
CONSTITUENTS：
chosen limited correlations
Morphology, distribution, crystallogprraphic info., concentration…
µ-structure
qs Properties
STEPPER：
Velocity, changing rate,
probabilistic parameter…

Procedures

Data mining: StatisticalCoarsening
anal. (Multiple regression*Comprehensive, panoramic
anal., response surface),view of all mater. behaviors
NN model, RBF network…
 Coarsening process thoroughly filters out a staggering amountof µ-structural information in a given complex 3D µ-structure Can also be answer to “Information explosion” in 4D imaging 30

Summary Recent 3D/4D imaging provides direct observation of complexand dynamic phenomena. Physical displacements of µstructural features have been used to obtain local ε, crack
driving forces and crystallographic information in 3D/4D.
Especially DAGT (Diffraction-Amalgamated Grain-boundaryTracking) technique provides a description of thecrystallographic orientations in polycrystalline materials from an
XRD analysis in addition to the morphological and mechanicalinformation obtained from the 3D imaging.
 ‘Reverse 4D Materials Engineering’ (R4ME), has been
proposed through the utilization of the advanced imaging andquantification techniques. It optimizes µ-structures by means ofan accurate image-based simulation in which multi-scale 3D
structures of existing materials are accurately reproduced.
Acknowledgement: Grant-in-Aids for Science Research (S)(FY 2012～2016) for R4ME and (A) (FY 2008～2012) for DAGT
31
from the Japan Society for the Promotion of Science (JSPS)