In order to study the damping mechanism of dislocation relaxation in Al, the internal friction of a high-purity Al crystal was measured for a frequency of 50kHz at between 2 and 240K. It was found that there were 3 temperature regions of dislocation peaks: the Bordoni relaxation (Bordoni peak at around 180K and Niblett–Wilks peak at around 120K), Lax–Filson peak at around 35K and the 11K peak. The change in the peak temperatures after slight deformation and annealing was checked in terms of the predictions of the kink pair formation mechanism. As a result, the 11K peak shifted to 10K with subsequent deformation, and returned to 11K with annealing. This agreed with the predictions of the kink pair formation mechanism. In the case of the Bordoni relaxation, however, the Bordoni peak shifted to lower temperatures and did not return to the original temperature after subsequent deformation and annealing. This could not be explained by the kink pair formation mechanism.

Observation of Dislocation Relaxation Peaks in Aluminium. T.Kosugi, K.Sakieda, Y.Kogure: Materials Science and Engineering A, 2006, 442[1-2], 147-50