A. Kurumada

K. Kawamata

N. Noda

O." Motojima

T. "Oku

Y. Imamura

Y. Kubota

National Institute for Fusion Science (NIFS-Repository)

§19. Joining of C/C Composite with Copper Using Titanium and Evaluation of Thermal and Mechanical Properties for Joining Materials Oku, T., Imamura, Y., Kurumada, A., Kawamata, K. (Fac-ulty of Engineering, Ibaraki University) Noda, N., Kubota, Y., Motojima, o. Joining specimens of a C/C composite and copper block wi th a cooling tube were manufactured for a mod!l of LHD divertor plate. Integrity and thermal and mechanical properties of the joining parts were evaluated by electron beam heating, three-point bending, continuous ind!ntation and microstructure examination tests. Fig.1 shows geometry of a divertor model specimen that is composed of a felt-type C/C composite (CX-2002U mad! by Toyo Tanso Co.) joined with oxygen-free copper block including a cooling tube by using only titanium foil. Electron beam heating tests were performed by ACT in NIPS. The energy of electron beam was 30keV, the heat flux was 8-15MW/m2 and the irradiation period was 20 seconds. The pressure, the speed and the temperature of cooling water at the inlet were 0.5MPa, 14.7m/s and 10-40t, respectively. A surface temperature of the C/C composite and the temperatures for upper and lower points of the joining part were measured by a radiation pyrometer and thermocouples. After heating tests, the divertor mod!l specimens were cut out and bending, continuous ind!ntation and microstructure examination tests were perfonned. Fig.2 shows a surface temperature of the C/C composite, upper and lower temperatures near the joining part shown in figure 1 for 10 heating cycles as a function of heat flux. Those temperatures increased with increasing heat flux. Fig.3 shows changes in temperatures for 100 heating cycles at 10 MW/m2 . Integrity of the joining parts has been preserved because those temperatures were lower than the joining temperature (1000t) chlring heating cycles. On the other hand, a surface temperature of a specimen which was heated for 4 heating cycles at 15MW/m2 increased rapicUy because there were some unusual conditions in the joining part. FigA shows bending strengths of the joining parts after heating tests at various heat fluxes. In this figure, a solid and dotted lines indicate the average and the standard deviation values for bending strength of the CX-2002U composite. Clearly, the bending strengths of specimens heated at 15MW/m2 d!creased and cracks by d!lamination were observed at the joining parts by SEM. In conclusion, integrity of this divertor mod!l specimen was confinned when the heat flux was lower than 12.5MW/m2 and the temperature of the joining part was lower than 800t. These results were presented at PSI meetings, International Symposium on Carbon Science and Technology for New Carbon (8-12/9/98, Tokyo) and JSME Ibaraki lecture meeting (25/9/98, Ibaraki). Electron Beam S ..... 15MW/m 2 Cooling Water -.,.-~...---"~~---..,, O.5MPa 14.7m/s ~---.~.,-Thennocouples #1 Cooling Tube r/J7 . Temp. ifr Thermocouples #2 Temp. #2 Fig.1 Geometry of a divertor model specimen. 1&00 r~~lr--'--'-T~""'--1----'---'-;::::C===l ! I ! 0 Surface Temp. 1400 ...... 1200 P ...., 1000 ., ::J ~ 800 Iil" ~ &00 400 200 o~~~~~~~~~~~~~~~~~~ & 10 12 14 16 Heat Flux ( MW/m2 ) Fig.2 Changes in temperatures as a function of heat flux. 400 .... n.................. .mIIIBffij.flljofljftl;.fjJftl1jflffiitfiJ_ ............ . ZOO~ •• ~ •••• ~ •••• ~ ••••~ .•••~ ....~.~ ....................... ~ .............. ~ ........... . 00 20 40 60 80 100 Shot Number Fig.3 Changes in temperatures during heating cycles. 50 ~~-----.~----~-----,-----.--~ ! 40 r:":"J": ":":: ":":": l :": ":":":"::"~ ":":":":": ":": ~::":":":": ":":": ":":":"-..J:::: I • en 30 i- .... • 5 i ~ ~--------------------------------------------cZi ! • OJ) 20 ~ ............................................. . !:: ' ] I (!) I • I=Q 10 ~ ............................................... . i 0~1--~--~----~----~----~·--Non Heated 8-12MW/m2 10MW/m2 12.5MW/m2 15MW/m2 FigA Bending strengths of the joining parts after heating tests. 87 

Joining of C/C Composite with Copper Using Titanium and Evaluation of Thermal and Mechanical Properties for Joining Materials

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