On the Deformation Induced Internal Friction Peaks in Niobium

Abstract

The activation energies and attempt frequencies for the deformation induced damping peaks in niobium are determined. For the α peak these are found to be 0.28 ± 0.01 eV and (2.8 ± 1.8) 1012s−1 from the variation of peak temperature with frequency and using all experimental data presently available. For the β peak, these parameters are estimated using strain recovery experiments performed during the warm‐up after plastic deformation at liquid nitrogen temperature. A value of 0.51 eV is found for 1012 s−1 and 0.48 eV for 1011 s−1, to be compared with values of 0.47 eV and about 1011 s−1 obtained by CHAMBERS and SCHULTZ from the shift of peak temperature with frequency. The width of the α peak is shown to be consistent with a relaxation process having a single attempt frequency, and a distribution of activation energies. Assuming a square distribution of width ΔH about H, it is found that ΔH|H ≈︁ 0.10.

Progress and problems in the understanding of the dislocation relaxation processes in metals

“…A few years after the mechanism of the Bordoni-type relaxation processes in fcc metals had become the subject of discussion, a search for analogous processes in bcc metals began [52][53][54][55][56][57][58]. By that time, striking differences between the deformation behaviour of fcc and bcc metals were already well established.…”

“…[56,58,90]). Recent summaries do not even mention the ␤-relaxation [25] or refer to it only incidentally [92].…”