1. Synthesis, characterization and FE-Modelling of a W/CuCrZr joint for extreme thermal applications EUROMAT 2011 – Montpellier 12-15-09.2011 A.Zivelonghi a, S. Nawka b, A. Brendel a, J.Riesch a, M.di Michiel c, M.Scheel c, T. Schubert d, J.-H. You a and B. Kieback b,d a IPP, Max-Planck-Institut für Plasmaphysik, Garching bei Munich, Germany b IfWW, Institut für Werkstoffwissenschaft, Technische Universität Dresden, Dresden, Germany c ESRF European Synchrotron Radiation Facility, Grenoble, France d IFAM, Fraunhofer-Institut für Fertigungstechnik und Angewandte Materialforschung, Dresden, Germany

2. Alessandro. Zivelonghi – Euromat 2011 Outline Conclusions & Outlook Materials for extreme thermal environments Synthesis of a W-CuCrZr multilayer FGM 1 Characterization Single layers manufactoring Assembling the multilayer Exp. measurements FE-Modelling (meso and macroscale) Optimization

3. Nuclear Fusion Reactors: High Heat Fluxes to be removed Materials for Extreme Thermal Environments Divertor (DEMO) ≥ 10 MW/m² ITER*, DEMO** *G.Federici, Journal of Nuclear Materials (2009) **H.Bolt et al., Journal of Nuclear Materials (2004) σ max (Interface) ~ Δα W-CuCrZr ΔT f(ΔE) Interface Stress FGM Joint CoolingOperation -800 MPa (compressive in W) H2OH2O Residual Stress [MPa] 550 MPa (tensile in W) *J.H.You, H.Bolt, Journal of Nuclear Materials 299 (2001) 1-8 Factor 4!

4. Alessandro. Zivelonghi – EUROMAT 2011 *Ge Ch-Ch. et al Mat. Science Forum 475-479 (2005) V p (z i ) = (z i /H) p i=1,..,n 4. Component Size 1. Higher Strength (W/Cu*  W/CuCrZr) W/Cu FGM Joint V p (z) = (z/H) p Continuous FGM-Joint* 2. Minimum Porosity + Good Homogeneity Requirements Sintering + Infiltration + CuCrZr-Hardening of Layered W-skeleton 3. Percolating CuCrZr-phase *Itho et al. Fusion Eng. and Design 31-4 (1996) PS Pores

5. Alessandro. Zivelonghi – Euromat 2011 1 2. Debinding (450°C, 30min) P (600-50 MPa)  W70-50 %vol ; W30 %vol no CP, no SH W-CuCrZr Single Layers * W-Skeleton full infiltration (with homog. microstructure and no cracks) only possible: 3. Sintering ((1200°C, 60min in H 2 ) 2. at low heating/cooling rates during 3,4 (internal stress to be relaxed, otherwise cracks) W/wax ratio [vol%]P [MPA]Por [vol %] 97.3/3.760030 (W70) 60/40 80/20 300 50 50 no cracks 100/0-70 (W30) 1. Cold Pressing (CP) + Space Holder (SH) 4. Infiltration (1200°C, 30min in Vacuum) 5. Hardening (970°C-RT + aging at 480°C, 60min) 1.in High Vacuum < 10 -3 mbar (bad wetting behavior in Ar / inhomog. precip. hard. In H 2 ) *S. Nawka et al., Proceedings of the PM2010 World Congress, 2010.

6. Alessandro. Zivelonghi – Euromat 2011 1 Assembling the FGM Multilayer W/wax ratio [vol%]P [MPa]Por [vol %] 97.3/3.750030 (W70) 55/4550050 (W50) 100/0-70 (W30) 1 Cold Pressing Close to zero porosity in ML 2 Debinding 3 Sintering4 Infiltration in High Vacuum5 Hardening

7. Alessandro. Zivelonghi – EUROMAT 2011 FE-Modelling FGM Joint under realistic conditions (residual and thermal stress) Development Strategy Joint optimization (manufacturing and HHF) Thermoelostoplastic Mat. Properties (including failure limits) Characterization single layers [ W30 %vol - W50 %vol - W70 %vol ]

8. Alessandro. Zivelonghi – EUROMAT 2011 Synchrotron Tomography W70 %vol W50 %vol W30 %vol Poster D32 - Zivelonghi et al. Cooperation with ESRF, beamline ID-15 J.Riesch Close to zero porosity good homogeneity W50 / W70 1 mm 0.4 mm

9. Alessandro. Zivelonghi – EUROMAT 2011 Composite Properties 1/2 [6] G. Pintsuk. et al Fus. Eng. Design (2003)

10. Alessandro. Zivelonghi – Promotionsprüfung 19.05.2011 3 Image-based FEM*Failure = f (…, internal RS, …) Mat. Properties 2/2 + Mesoscale Modeling W30 [%vol] W70 [%vol] W30 [%vol] *A.Zivelonghi, Ph.D. Thesis, 2011, pp 51-84 - Thermomech. Behaviour of Two Heterogeneous Tungsten Materials via 2D and 3D Image-based FEM 100 µm Elongation and failure limits

11. FEM: Residual Stress after Infiltration possible delamination and infiltration of CuCrZr at the interface W-W70 Below plastic failure limits

12. Alessandro. Zivelonghi – EUROMAT 2011 FEM: T-Profile in Mockup Mockup for High Heat Flux Tests Previous design: W-fibers-MMC FGM-ML Decrease of Max. Temperature ~ 80°C T [°C] W-tiles CuCrZr Joint 10.5 MW/m²

13. …varying h1, h2, h3 1.Residual stress (manufacturing ML+W-tile) 2. Thermal stress (steady-state operation ~ 10MW/m²) FEM: towards optimization Minimizing…

14. Alessandro. Zivelonghi – EUROMAT 2011 W30 [%vol] W70 [%vol] [MPa] Max S: 513 MPaMax S: 611 MPa Opposite trends: Infiltration vs Operation ! S-Mises [MPa] W30 W70 W-tile CuCrZr W-tile

15. Alessandro. Zivelonghi – EUROMAT 2011 Conclusions & Outlook Future Steps - FE-Modelling procedure for ML-design optimization established - Characterization behaviour single-layer - Manufacturing of 3layers-FGM (close-to-zero porosity) FGM Mockup with optimized design + exp. HHF campaign (GLADIS) - “Upgrade” W/Cu  W/CuCrZr achieved Thank you! Acknowledgement The authors are thankful to the Deutsche Forschungsgesellschaft (DFG) for funding the project and to the ESRF for technical support

16. Alessandro Zivelonghi – EUROMAT 2011 Opposite trends: Infiltration vs Operation ! Max S: 676 MPa 2. Minimizing Thermal Stress during Operation Max S: 513 MPaMax S: 611 MPa S-Mises [MPa] W30 W70 W-tile CuCrZr

17. Mesh Dependency 1 ΔT = +800 °C

18. Mesh Dependency 2 ΔT = +800 °C

19. Mesh Dependency 3