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)

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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