LOW-TEMPERATURE ANELASTIC BEHAVIOR OF NIOBIUM CONTAINING HYDROGEN

The elastic constants and attentuation of niobium with low concentrations of oxygen and hydrogen have been measured as a function of temperature, frequency, polarization, and hydrogen isotope. The measurements were made in the temperature range 0.5 to 15 on Nb–(D) specimens in which the H-(D) was kept in solution by trapping at O solutes. Two relaxation processes were observed for the C mode. No observable relaxations appeared in the C44 or the bulk modulus. At 10 MHz these relaxations occurred at 2.4 and 5.5 for H. The relaxations exhibited an isotope shift to higher temperatures in D alloys. The lower temperature relaxaion process has a strength which is linear in hydrogen concentration while the second process is nonlinear.The results will be discussed in terms of a delocalized wave model. © by Akademische Verlagsgesellschaft