Aging effect for hydrogen embrittlement behavior on Ta-Zr alloy

Kaneda, Tomohiro*; Yokoyama, Kenichi*; Ishijima, Yasuhiro ; Ueno, Fumiyoshi  ; Abe, Hitoshi 

In spent nuclear fuel reprocessing plant, Zr/Ta dissimilar metal joint is used for connect between different devices. And it is known that Zr and Ta have susceptibility of hydrogen embrittlement. The other hand, Zr and Ta are alloyed in the dissimilar joint and it is not clear that the hydrogen embrittlement behavior of the Zr-Ta alloy. This study aims to elucidate the hydrogen embrittle behavior of the Zr-Ta alloy. Tensile tests and X-ray diffraction (XRD) were carried out after hydrogen charging in 0.9% NaCl solution. The zirconium hydride was detected by XRD analysis but embrittlement was not shown by tensile tests. However, brittle fracture patterns were observed by SEM observation at the fracture surface the specimen after tensile test. It is consider that these results suggest the zirconium hydride that formed by hydrogen charging dominates the hydrogen embrittlement behavior of the Zr-Ta alloy.