[3A01-04] Reactor Component Technology

[3A03] Fabrication of W/RAFM steel joint by combined joint method

*Toyo Yamashita¹, Masayuki Tokitani², Hiroyuki Noto², Yukinori Hamaji², Jingjie Shen², Suguru Masuzaki², Takeo Muroga², Takashi Nozawa³, Hiroyasu Tanigawa³ (1. SOKENDAI, 2. NIFS, 3. QST)

Keywords:divertor, tungsten, RAFM steel, brazing, diffusion bonding

A combined joint method between W and reduced activated ferritic/martensitic (RAFM) steel with pure-copper (Cu) interlayer was newly developed. In this method, firstly, W and Cu is jointed by brazing. Secondly, Cu and RAFM steel is jointed by diffusion bonding without any insert materials. The advantages of this method are that since no insert material between Cu and RAFM steel, undesired phase transformation and embrittlement in RAFM steel can be avoided as much as possible. This report would like to focus on the microstructural transformation of RAFM steel. We confirmed that there is almost no microstructural transformation in RAFM steel after the joint heat treatment at below 730℃ by transmission electron microscope (TEM) observation.