Effect of hydrogen on internal friction and elastic modulus in titanium alloys

The effect of hydrogen on the variation with temperature of internal friction (Q−I) and elastic modulus (E) of a number of Ti-based alloys has been studied in the Hz and kHz frequency ranges. A relaxation peak of internal friction with a high degree of relaxation (Q−Imax ∼ 10−1) and with a ΔE effect is observed in all hydrogen-doped samples at T ∼ 600 K at ∼1 kHz, and at T ∼ 500 K at ∼1 Hz. Such a peak is not present in samples without hydrogen. The activation energy W and the frequency factor v0 of the observed relaxation are determined to be W ∼ 1.55 eV, v0 ∼ 1017 s−1. It is shown that the observed effects are connected with the mechanism of grain boundary relaxation, as the introduction of hydrogen into titanium alloys leads to the formation of fine-grained structures.