SNOEK-KOSTER RELAXATION IN Ta-O SOLID SOLUTIONS
Ta—O固溶体中的Snoek—Koster驰豫

After coating the specimen with a thin Ti layer, the Snoek-Koster relaxation is systematically investigated without the effect of oxygen pick up. Two relatively stable internal friction peaks, SK1 at lower temperature and SK2 at higher temperature, are observed in deformed Ta-O samples. The changes of their peak shape and stability with annealing at different oxygen content are experimentally studied. The activation energies of SK1 and SK2 are measured to be 1 .4 and 2.1 eV respectively. It is suggested that the SK1 corresponds to the geometrical kink migration on screw dislocations and the SK2 corresponds to the formation and migration of kink-pairs on screw dislocations. From experimental results it is estimated that the energy of kink pair formation is about 0.9 eV and the binding energy of screw dislocation with oxygen atom is about 0.3 eV. It is additionally found that the height of the Snoek peak does not change after further deformation.