On the Deformation Induced Internal Friction Peaks in Niobium

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) 10 12 s −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 10 12 s −1 and 0.48 eV for 10 11 s −1 , to be compared with values of 0.47 eV and about 10 11 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 Δ H about H , it is found that Δ H | H ≈ 0.10.