Guo Shi-bin, Ling Yun-han, Li Jiang-tao Technical Institute of Physics and Chemistry, CAS

1. HT-7 Data Meeting Thermal shock and plasma irradiation performances of the W/Cu FGM fabricated by combustion synthesis melt-castingunder ultra-high gravity Guo Shi-bin, Ling Yun-han, Li Jiang-tao Technical Institute of Physics and Chemistry, CAS Tsinghua University 2011-7-19,Hefei

2. Outline PWI --- Thermal-Physical Behavior of PFM under high heat flux load The new method of producing W/Cu FGM by combustion synthesis melt-casting under ultra-high gravity, CSMC-UHG The W plate and the W/Cu FGM joint Thermal shock performance by DC arc plasma jet Plasma irradiation performance in HT-7 tokamak Conclusions

3. Thermal-Physical Behavior of PFM • W is being regarded as the most promising candidate for PFM because of the： • High Tm • Low physical sputtering • No Chemical reaction with H • Low T retention • The thermal-physical behavior of W is one of the most Important issue in PWI, which determines in a great degree the performance of the plasma. • The following questions will arise due to the plasma erosion on W： • High heat flux H/He erosion cause not only the surface damage but also matrix degradation； • Self sputtering of the high Z element contaminates the plasma。 • 14.1 MeV neutron radiation, and subsequent property degradation.

4. Motivation • The present project aims at characterize the thermal-physical behavior of W when subjected to plasma irradiation by experimental simulation, so as to understand the thermal-physical behavior of W under high heat flux load and neutron irradiation. • To develop a new way of producing W/Cu material with designed microstructure and controlled properties.

5. The thermal-physical properties of W and Cu High heat flux W CTE:4.5×10-6/K Thermal stress mismatch Cracks Failure Cu CTE:17×10-6/K W W/Cu FGM CuCrZr Cooling water

6. Production of W/Cu FGM by CSMC-UHG, ---- Combustion synthesis melt-casting under ultra-high gravity A new method

7. Principles of the CSMC-UHG 2Al+xCuO+yWO3+(mW/nCu)(y+m)W/(x+n)Cu + Al2O3，Tad=2000~4000K Combustion reaction Ultra-high Gravity + Generate ultra-high temperature followed by molten phases formation Exert ultra-high centrifugal force followed by phase separation W/Cu FGM

8. 0% A Cu E Cu100 100μm W profile B F W W66Cu34 Cu W 100μm C G W W71Cu29 Cu W 100μm W D H W75Cu25 Cu W 75% 100μm W and Cu profiles in the W/Cu FGM A, B, C, D show the SEM patterns at the different area of the W/Cu FGM side ; E, F, G, H show the EDS spectra for A, B, C, D respectively.

9. W plate and W/Cu FGM joint W plate Ф40mm Cu foil W/Cu FGM 10μm Pure W plate and W/Cu FGM joint tightly by Cu foil

10. Thermal shock experiment DC arc plasma jet H Plasma W/Cu FGM W/Cu FGM Before shock After shock Energy flow: 5.33MW/m2 Surface Temp.：~1000℃ Shock time: >2h Without cracks and failure by eyes

11. Thermal shock performance 5μm 20μm 10μm H ion etched the impaired surface of W plate Rough lines at the surface Mismatch at the interface between W plate and Cu foil but not failure

12. Plasma irradiation in HT-7 R: 270~280mm, Ip: 120~200KA, Ne: 0.8~1.5×1019/m3, T: ~225℃, total time: ~30min

13. CH09 : W/Cu FGM (No cooling) CH09 : W/Cu FGM (No cooling) T: ~225℃ T: ~52℃ Temperature response at R280mm and R270mm The temperature of W/Cu FGM is the same range as one of other limiters at R280mm The temperature of W/Cu FGM is greater than that of other limiters at R270mm

14. Change after plasma irradiation at R270mm UV-Vis reflectance spectra Before plasma irradiation The surface roughness of the W/Cu FGM increases after plasma irradiation at R270mm After plasma irradiation

15. 25μm 5μm 25μm 5μm Plasma irradiation performance Comparison between R280mm and R270mm R 280mm Surface R 270mm Surface cracks R 280mm Interface R 270mm Interface Cu foil W 10μm 10μm

16. Plasma irradiation performance Comparison between W/Cu FGM and stainless steel (R270mm) Particles etch at the damaged area Cracks generating Particles impact all the area Micro-holes generating

17. Conclusions • W/Cu functionally-graded materials have been prepared by combustion synthesis melt-casting under ultra-high gravity. • The W plate and W/Cu FGM have been jointed tightly by the Cu foil. • Thermal shock performance has been evaluated by DC arc plasma jet. The W/Cu FGM can endure 5.33MW/m2 energy flow. • Plasma irradiation performance has been evaluated in the HT-7 tokamak. The W/Cu FGM can resist particles irradiation during the short burst.

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