On the deformation induced internal friction peaks in niobium

The activation energies and attempt frequencies for the deformation induced damping peak.s 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 warming-up after plastic deformation at liquid nitrogen temperature. A value of 0.51 eV is found for 10¹²s^-1 and 0.48 eV for 10¹²s^-1, to be compared with values of 0.47 eV and about 10¹²s^-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/H ≈ 0.10.