27pB04
HIP法によるW/V/Au/ODS-Cu接合の開発研究
Development of high strength W/V/Au/ODS-Cu joint using HIP process
能登 裕之1、山田 哲也2、菱沼 良光1、室賀 健夫1
Hiroyuki NOTO1, Tetsuya Yamada2, Yoshimitsu Hishinuma1, Takeo Muroga1
1
核融合科学研究所、2名古屋大学大学院
1
National Institute for Fusion Science, 2Nagoya University
The divertor with higher heat removal
capabilities and heat resistance to severe heat andparticle load are one of the key components tooperate fusion reactors. One of the candidate
material combination for fabricating the divertor istungsten (W) and copper (Cu) alloy because W andCu have promising properties for the divertor
application. W has high melting point, lowhydrogen isotope retention, low sputtering yield,
and so on. Cu alloy has higher thermal conductively
compared with the other metal materials. In fact,copper alloy (Cu-Cr-Zr) pipes are tried to join with
W by conventional brazing on the ITER project. On
the other hand, oxide dispersion-strengthened
copper alloys (ODS-Cu) such as GlidCop®
(Cu-0.3wt%Al2O3) has superior mechanicalproperties at high temperatures than Cu-Cr-Zr, andthus can be an advanced candidate for the divertor
components. Therefore, the establishment of thebonding process between W and ODS-Cu is an
essential technology to succeed the divertor systemusing ODS-Cu.
W and Cu are almost insoluble with each other andthey have very different coefficient of thermalexpansion (CTE). Thus, the insert materials
between W and ODS-Cu is expected to be effective
to the bonding.
In this study, vanadium (V) and gold (Au) areselected as interlayers to the joint between W andODS-Cu. These layers have advantage for theW/ODS-Cu bonding such as high solubility,plasticity and thermal conductivity, and low
activation. V and Au have extremely different
melting points, these metal expected to use as a new
bonding material based on diffusion reaction. The
new bonding proceeded with two steps. The firststep is the W/V bonding by solid-phase diffusion
reaction. The second step is the W-V/Au/ODS-Cu
bonding using the Hot Isostatic Press (HIP). The
HIP process condition was 950 ˚C for 1 hr in argon
atmosphere of 200 MPa. The melting point in theinterface between Au and ODS-Cu is decreased by
the eutectic reaction, and referred as the TransientLiquid Phase bonding. In this study, Au inserts wascompared Thickness of 0 and 0.7 μm, 300 μm

which fabricated as no inserts and physical Vapor
Deposition (PVD), foil, respectively.
The smooth interfaces without reaction layers
and large defects were observed in the W/V andAu/ODS-Cu interface. However, the hardenedregion (300 μm) by V/Au reaction were observed inthe V/Au interface region.
In the case of joints using extremely thin inset(0.7 μm), the inter-diffusion layer was not observedin interface of V/GlidCop®(Cu) as shown Fig.1.

Fig.1 SEM image of the cross section area ofV/GlidCop®(Cu) joint with PVD-Au, showing
hardness profile measured by Nano-indentation
method. This hardness profile means that thehardening induced solution of Au in parent metals
did not generate, and inter-metallic compound did
not formed. In addition, residual of Au was notobserved by composition analysis. It is consideredthat this joints reached homogenization without
localization of Au elements. Thus joints withPVD-Au has a beneficial effect of suppressing theformation of brittle region.
In addition, the overall bending strength of the
W/V/Au/ODS-Cu joints using HIP process will bereported.