Hydrogenation Behavior in Ti-Cr Alloys with Compositions around TiCr2 Laves Phase

Hydrogenation behavior in Ti–Cr alloys with compositions around TiCr2 Laves phase has been examined by the tritium radioluminography and the PCT measurement. All of the specimens have been two-phase structure of BCC phase and Laves phase. The ratio of the BCC phase to the Laves phase has been increased as increasing the heat treatment temperature. The Ti-rich BCC phase and Cr-rich BCC phase have been formed in the Ti50Cr50 alloy and the Ti30Cr70 alloy, respectively. It is found that hydrogen easily penetrates into the Laves phase in the initial stage of hydrogen penetration. In the PCT measurements, Ti50Cr50 alloy absorbed the largest amount of hydrogen. The maximum protium storaging capacity of 3.5 mass% was obtained in the Ti50Cr50 specimen heat treated at 1400°C at the measured temperature of 150°C. The plateau of PCT curves in Ti50Cr50 alloy and Ti30Cr70 alloy appeared at low hydrogen pressure and high hydrogen pressure region, respectively. These plateaus are attributed to the Ti-rich BCC phase and the Cr-rich BCC phase, respectively.