ABSTRACT
Although the Granato-Lücke thery of amplitude independent dislocation damping is formulated nearly thirty years ago, no unambiguous experimental proof without contradictions or without additional assumptions has been given yet. In the present work an extremely thorough testing has been carried out by measuring the frequency dependence (10–200 MHz) simultaneously of attenuation and sound velocity, by additionally determining the loop length dependence with the help of γ irradiation, and by changing the initial loop length by using different qualities of high purity copper. For this purpose a special technique for measuring the frequency dependence of damping and velocity with the necessary high accuracy had to be developed and copper samples of extreme purity had to be produced. As result it was found that all measurements could be quantitatively interpreted with good accuracy by the Granato-Lücke theory under the assumption of an exponential loop length distribution. Only in case of specimens which were deformed before, a second component characterized by longer loops appeared. The general situation concerning the understanding of dislocation resonance has been discussed.
