Thermal shock and plasma irradiation

performances of the W/Cu FGM fabricated

by combustion synthesis melt-casting

under ultra-high gravity

Guo Shi-bin, Ling Yun-han, Li Jiang-tao

Technical Institute of Physics and Chemistry, CASTsinghua University

2011-7-19,Hefei

HT-7 Data Meeting

OutlineOutline

1. PWI --- Thermal-Physical Behavior of PFM under high heat flux load

2. The new method of producing W/Cu FGM by combustion synthesis melt-casting under ultra-high gravity, CSMC-UHG

3. The W plate and the W/Cu FGM joint

4. Thermal shock performance by DC arc plasma jet

5. Plasma irradiation performance in HT-7 tokamak

6. Conclusions

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.

Thermal-Physical Behavior of PFMThermal-Physical Behavior of PFM

MotivationMotivation

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.

The thermal-physical properties of W and Cu

Mater. Density(g/cm3 )

Tm(K)

CTE(10-6/K )

TC (W/m·K )

Yang’s Modulus

(GPa)

Hardness(MPa)

Resistivity(x10-5 ·m)

Tensile Strength( MPa )

W 19.3 3673 4.5 145 410 300-400 550 1920

Cu 8.9 1356 17 400 85 50 1.78 314

WCTE:4.5×10-6/K

CuCTE:17×10-6/K

High heat flux

Cooling water

Thermal stressmismatch

Cracks

Failure

W

W/Cu FGM

CuCrZr

Production of W/Cu FGM by CSMC-UHG,

---- Combustion synthesis melt-casting under

ultra-high gravity

A new method

Principles of the CSMC-UHG

Combustion reaction + Ultra-high Gravity

Generate ultra-high temperature followed bymolten phases formation

Exert ultra-high centrifugal force

followed by phase separation

W/Cu FGM

2Al+xCuO+yWO3+(mW/nCu)(y+m)W/(x+n)Cu + Al2O3 ， Tad=2000~4000K

W and Cu profiles in the W/Cu FGM

0%

75%

W p

rofile

Cu

CuW

Cu

W

Cu

W

A

B

C

D

E

F

G

H

Cu100

W66Cu34

W71Cu29

W75Cu25

100μm

100μm

100μm

100μm

W

W

W

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.

W plate and W/Cu FGM joint

10μm

W plate

W/Cu FGM

Cu foil

Ф40mm

Pure W plate and W/Cu FGM joint tightly by Cu foil

Thermal shock experiment

W/Cu FGM

H Plasma

Energy flow: 5.33MW/m2

Surface Temp. ： ~1000℃

Shock time: >2h

DC

arc plasm

a jet

Without cracks and failure by eyes

Before shock After shock

W/Cu FGM

Thermal shock performance

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

20μm

5μm

10μm

Plasma irradiation in HT-7

R: 270~280mm, Ip: 120~200KA, Ne: 0.8~1.5×1019/m3,

T: ~225℃, total time: ~30min

Temperature response at R280mm and R270mm

0 200 400 600 800 1000 1200 140020

30

40

50

60

Tem

pera

ture

(℃

)

Time (min)

CH09 CH05 CH08 CH10

CH09 : W/Cu FGM

(No cooling)

T: ~52℃

0 200 400 600 800 1000 1200 14000

50

100

150

200

250

300

Tem

pera

ture

(℃)

Time (min)

CH09 CH05 CH08 CH10

CH09 : W/Cu FGM

(No cooling)T: ~225℃

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

Change after plasma irradiation at R270mm

Before plasma irradiation

After plasma irradiation

The surface roughness of the W/Cu FGM increases after plasma irradiation at R270mm

UV-Vis reflectance spectra

Plasma irradiation performance Comparison between R280mm and R270mm

25μm

5μm

25μm

5μmcracks

10μm 10μm

R 280mm

Surface

R 280mm

Interface

R 270mm

Surface

R 270mm

Interface W

Cu

foil

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

Conclusions

1. W/Cu functionally-graded materials have been prepared by combustion synthesis melt-casting under ultra-high gravity.

2. The W plate and W/Cu FGM have been jointed tightly by the Cu foil.

3. Thermal shock performance has been evaluated by DC arc plasma jet. The W/Cu FGM can endure 5.33MW/m2 energy flow.

4. Plasma irradiation performance has been evaluated in the HT-7 tokamak. The W/Cu FGM can resist particles irradiation during the short burst.