Hydrogen permeation characteristics of (V, Ta)-Ti-Ni alloys

Hydrogen permeation properties and microstructures of V-Ti-Ni and Ta-Ti-Ni alloys were investigated at 523-673 K. In both systems, a good hydrogen permeability was obtained in the alloys whose chemical compositions are near TiNi-V (or Ta) pseudo-binary system without hydrogen embrittlement. These alloys consist mainly of B2-TiNi and bcc-(V, Ti) (or bcc-(Ta, Ti)) phases. In particular, hydrogen embrittlement resistance is improved by the combination of the primary bcc phase and the eutectic B2+bcc structure. The primary bcc phase and the eutectic B2+bcc structure contribute mainly to hydrogen permeability and to improvement of hydrogen embrittlement, respectively. This paper shows a possibility of new type multi-phase hydrogen permeation alloys.