Tungsten as Structural Material

Transcription

1 Tungsten as Structural Material for Power Plant High Heat Flux Components Michael Rieth & Andreas Hoffmann Thanks for contributions and discussions to: S. Baumgärtner, C. Bichler, B. Dafferner, C. Grubich, S. Heger, U. Jäntsch, M. Klimenkov, W. Krauss, P. Lukits, E. Materna-Morris, A. Möslang, P. Norajitra, J. Reiser, M. Rohde, W. Schulmeyer, R. Ziegler, H. Zimmermann KIT die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Contents - Overview - Materials & Microstructure - Strength - Thermal Conductivity - Toughness - Conclusions and Outlook

2 Overview, DEMO Divertor Design 10 MW/m² ELMs, high energetic particles, etc C 1200 C (Brazed Joint) 700 C (Brazed Joint) Tile (W) Thimble (W- Material) Conic Sleeve (ODS Steel) ODS Steel Cartridge (W, Steel) P. Norajitra, this workshop 2 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

3 Materials Densimet WL10 3 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

4 Material Production Routes 4 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

5 Important Design Criterions Starting Point in 2006 commercial 8 mm W rod n 5 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

6 Present Knowledge: Creep \l(1) WL10 plate (4 mm) 6 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

7 Present Knowledge: Creep commercial 8 mm WL10 rod (weld electrode) commercial 8 mm W rod (weld electrode) n 7 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

8 Present Knowledge: Recrystallization Microstructure in the condition as delivered (by TEM) WL10 Rod, Ø7 mm W Rod, Ø7 mm 8 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

9 Present Knowledge: Recrystallization Microstructure perpendicular to rod axis (by optical microscope) W Rod, Ø10 mm, as delivered W Rod, Ø10 mm, 1300 C/343 hours 50 µm 50 µm 9 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

10 Present Knowledge: Recrystallization Microstructure parallel to rod axis (by optical microscope) WL10 Rod, Ø10 mm, as delivered WL10 Rod, Ø10 mm, 1300 C/1966 hours 50 µm 50 µm 10 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

11 Present Knowledge: Recrystallization Observed recrystallization compared to existing results (Ref.: Plansee) W + 1% La 2 O 3??? not recrystallized start of recrystallization 1 h 2 h 8 h 200 h W Design Limit??? h 11 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

12 Present Knowledge: Th. Conductivity parallel to rod axis perpendicular to plate Design Limit 12 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

13 Materials, Rolling Texture 6 RODS 4 PLATES 13 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

14 Microstructure WL10 Rod, Ø7 mm longitudinal transverse 14 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

15 Microstructure W-1%Re-1%La 2 O 3 Rod, Ø10 mm longitudinal transverse 15 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

16 Present Knowledge: DBTT Design Limit Densimet 16 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

17 Present Knowledge: DBTT 7 mm WL10 rod commercial 8 mm W rod (weld electrode) n 17 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

18 High Temperature Charpy Tests vacuum: ~10-6 Bar / ~1150 C tup support specimen drop weight design, vacuum vessel opened furnace: view on support 18 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

19 Results, Rod Materials DELAMINATION 19 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

20 Fracture: W & WL10, 7 mm rods W: 7 mm rod, EDM WL10: 7 mm rod, EDM 20 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

21 Surface Fabrication 50 µm 50 µm W Rod, EDM W Rod, Diamond Saw 21 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

22 Delamination, Simple Analogy a 4 b 1 3 c 3 22 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

23 Results, Surface Fabrication 23 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

24 Discussion Shift due to surface cracks fabrication issue Shift due to load specimen geometry (stress concentration) Delamination crack initiation fabrication issue 24 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

25 Results, Plate Materials DELAMINATION 25 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

26 Fracture: W & WL10, plates W WL10 26 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

27 Discussion GB weakening type, size, distrib. of oxides grain shape, orientation, etc. Base Material: Mo - W DBTT characteristic 27 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

28 Present Knowledge: DBTT 7 mm WL10 rod commercial 8 mm W rod (weld electrode) 7 mm W rod n 28 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008

29 Conclusions Long-term creep strength and recrystallization behavior have still to be examined Microstructure significantly defines transition temperatures (rod texture more favorable than that of plates) Oxide particles (and also potassium doping) promote delamination (but they are necessary for stabilizing GB suppr. re-crystallization) Tungsten materials have a DBTT limit of 400 C (when produced by sintering & deformation, tested according to DIN EN ISO 148-1, ) Notches/edges have to be avoided in structural parts Optimum fabrication probably only by aligning grains along the contour of the according part deep drawing, twisting, pressing, 29 M. Rieth, A. Hoffmann HHFC, San Diego December 10, 2008