Synthesis, characterization and FE-modeling of a W/CuCrZr FGM joint
EUROMAT 2011 – Montpellier 12-15-09.2011
a IPP, Max-Planck-Institut für Plasmaphysik, Garching bei Munich, Germanyb IfWW, Institut für Werkstoffwissenschaft, Technische Universität Dresden, Dresden, Germanyc ESRF European Synchrotron Radiation Facility, Grenoble, Franced IFAM, Fraunhofer-Institut für Fertigungstechnik und Angewandte Materialforschung, Dresden, Germany
A.Zivelonghia, S. Nawkab, A. Brendela, J.Riescha , M.di Michielc, M.Scheelc, T. Schubertd, J.-H. Youa and B. Kieback b,d
Outline
Conclusions & Outlook
Introduction Synthesis of a W-CuCrZr multilayer FGM
1
Characterization
Single layers manufactoring
Assembling the multilayer (ML)
Experimental measurements
FE-Modelling (meso and macroscale)
Optimization
EUROMAT 2011
Nuclear Fusion Reactors High Heat Fluxes on first wall to be removed
Materials for Extreme Thermal Environments
≥ 10 MW/m² ITER*, DEMO**
*G.Federici, Journal of Nuclear Materials (2009) **H.Bolt et al., Journal of Nuclear Materials (2004)
Interface Stress
FGM Joint
H2O
W: good plasma compatibility, highest Tm, high strength at high T
Cu: high conductivity, limited oper. T (< 300°C)
CuCrZr: improved strength (RT-550°C) higher operation T (up to 480°C)
higher power generat. efficiency
Plasma FacingComponent
2 cmEUROMAT 2011
EUROMAT 2011
W-Cu: High Mismatch Stress
σmax (Interface) ~ f(ΔαW-CuCrZr , ΔE, ΔT...)
CoolingOperation
550 MPa (tensile in W)
*J.H.You, H.Bolt, Journal of Nuclear Materials 299 (2001) 1-8
Sx
[MPa]-800 MPa
(compressive in W)
factor 4!10 MW/m²
5. Component size
1. Graded transition (layered or continuous)
Satisfying Demanding Requirements
3. Minimum porosity + good homogeneity
Requirements
4. High conductivity percolating CuCrZr
2. Higher strength (W/Cu* W/CuCrZr)
Sintering of Layered W-skeleton(100% open porosity)
+Infiltration
CuCr0,8Zr0,08 (wt%) +
Hardening
INFILTRATIONItho (1996), Ge (2005)R. Jedamzik (2000)D. Jankovic Ilic
Plasma SprayedPintsuk (2004), Ge (2005)
SPSiGe (2005)
W/Cu
FE-Modelling FGM Joint under realistic conditions
(residual and thermal stress)
Development Strategy
Joint optimization (ongoing)
Thermoelostoplastic Mat. Properties(including failure limits)
Characterization single layers [ W30%vol - W50%vol - W70%vol ]
2. Debinding (450°C, 30min)
W-d50=4µm, SH-d50=12µm CP (600-50 MPa) W70-50%vol ; / W30%vol no CP, no SH
W-CuCrZr Single Layers*W
-Sk
ele
ton
full infiltration without cracks only possible:
3. Sintering ((1200°C, 60min in H2)
- at low heating rates (<10K/min) during 2, 3 and 4 (internal mismatch stress to be relaxed)
1. Cold Pressing (CP) + Space Holder (SH)
4. Infiltration (1200°C, 30min)
5. Hardening (ann.+ quenching 970°C-RT + aging at 480°C, 60min)
- in Vacuum (< 10-3 mbar) during 4 (Infiltration)
*S. Nawka et al., Proceedings of the PM2010 World Congress, 2010.
CuCrZrbad wetting behavior in Ar (CrxOy, ZrxOy, diffusion on surface)inhomog. precip. hard. in H2
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W70-CuCrZr30(%vol)
W54CuCrZr46(%vol)
W31CuCrZr69(%vol)
W-CuCrZr Single Layers
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1
Assembling the FGM Multilayer
W/wax ratio [vol%] P [MPa] Por [vol %]
97.3/3.7 500 30 (W70)
55/45 500 50 (W50)
100/0* - 70 (W30)
1 Cold Pressing
2 Debinding 3 Sintering
4 Infiltration 5 Hardening
10 mm
Close to zero porosity in ML (<0.1% on 80 mm²)
Residual porosity in CuCrZr
*Form tapping (n=50)
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Synchrotron Tomography
W70%vol
W50%vol
W30%vol
Poster D12-P-2-05
Cooperation with ESRF, beamline ID-15
< 1% porosity on 10 mm³good homogeneity W50 / W70
1 mm
Spatial Res. Limit (WB at 100 KeV): 2.2µm/px
W high Z strong X-Ray absorption
W/CuCrZr Mechanical Properties 1
* G. Pintsuk. et al Fus. Eng. Design (2004)
*
** Cu 99.9-99.95%
**
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Bending Test
W/CuCrZr Mechanical Properties 2
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W30[%vol] W70[%vol]
Tensile Tests at different T
W/CuCrZr Thermal Properties
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Image-based FEM*
Modeling Yielding and Failure at the Mesoscale
W30[%vol]
W30[%vol]
100 µm
Elongation and failure limits
Internal residual stress strongly influencing yielding and failure
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FEM Macroscale: Residual Stress after Infiltration
possible damage in W
Avg plastic strain in single layersbelow failure limits
…varying h1, h2, h3
1. Residual stress (manufacturing ML+W-tile)
2. Thermal stress (steady-state operation ~ 10MW/m²)
FEM: Towards Optimization
Minimizing…
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Minimizing Residual Stress after Infiltration
W30[%vol]
W70[%vol]
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Max S: 513 MPa Max S: 611 MPa
S (Mises) [MPa]
W30W70
W-tile
CuCrZr
T [°C]
Mockup for High Heat Flux TestsW-tiles
CuCrZr
Joint
10.5 MW/m²
Opposite optimization trends: Infiltration vs Operation !
Minimizing Thermal Stress (Component Level)
EUROMAT 2011
Summary & Outlook
Future Steps
- Good strength and th.conductivity for the single compositions achieved
- Manufacturing of W-Tiles+3layers-FGM with percolating mesostructure and close-to-zero porosity ML shown
Mockup with optimized design + exp.
FATIGUE campaign (High Heat Flux
Test Facility GLADIS)
- “Upgrade” W/Cu W/CuCrZr successfully achieved while limiting the oxide formation and keeping good PH features
- Identification of two opposite design optimization trends (Infiltration vs Operation)
The authors are thankful to the Deutsche Forschungsgesellschaft (DFG)
for funding the project
Acknowledgement
T. Schubert, B.Kieback
J.Riesch, V.Pfaffenholz, M.Köppen, J.Du, F. Koch, G. Matern
M.di Michiel, M.Scheel
S.Nawka, F.Hennig
W70-CuCrZr30(%vol)
W54CuCrZr46(%vol)
W31CuCrZr69(%vol)
W-CuCrZr Multilayer
Alessandro Zivelonghi – EUROMAT 2011
Opposite trends: Infiltration vs Operation !
Max S: 676 MPa
2. Minimizing Thermal Stress during Operation
Max S: 513 MPa Max S: 611 MPa
S-Mises [MPa]
W30W70
W-tile
CuCrZr