The internal friction response and elastic modulus of hydrogenated ß-type alloys were measured by using torsional and flexural vibration modes. The [H]/[M] ratio ranged from zero to unity. Two types of internal friction peak were detected. One was a relaxation peak which occurred at 84 or 123K, and frequencies of 2Hz or 1.5kHz, respectively. This was attributed to the Snoek-type behavior of dissolved H. The associated activation energy was about 16kJ/mol; regardless of the H content. A hydride precipitation peak occurred in alloys with [H]/[M] ratios which were greater than 0.6. The temperature at which it appeared depended markedly upon the H content. It was deduced, from the relaxation parameters of the Snoek-type peak, that the H diffusivity was described by:

D (m2/s) = 3.6 x 10-10 exp[-16.4(kJ/mol)/RT]

K.Kato, O.Yoshinari, K.Tanaka: Transactions of the Japan Institute of Metals, 1988, 29[4], 251-7