J. Phys. Colloques 32 (1971) C2-152-C2-152
INTERNAL FRICTION MEASUREMENTS IN ALUMINIUM DURING γ-RAY AND ELECTRON IRRADIATIONH. R. KAUFMANN and G. ROTH
By Measuring the damping in the kHz and MHz region on Cu, Pb and Zn during and after electron and γ-ray irradiation several dislocation pinning and depinning stages have been found in these metals. In the present work the investigations have been extended to Aluminium. The MHz-experiments were performed with undeformed and slightly deformed Al-single crystals of different purity and 3-MeV-γ-irradiation. The temperature of irradiation was varied from 80 °K to 420 °K and the dose from 125 to 6 000 µAh where 1 µAh ≈ 1 x 1010 point defects/cm3 . In none of these experiments, however, an influence of the irradiation on the MHz absorption was observed In the kHz-experiments the effects of electron irradiation on the internal friction and Young's modulus of polycrystalline samples under electron irradiation up to an integrated electron flux of 1 x 1018 electrons/ cm2 have been investigated. Also here no effect of the irradiation upon the damping could be observed. The modulus, however, showed an increase which was comparable to that found in copper. These results seem to lead to the conclusion, that also in the case of A1 dislocations are pinned by irradiation induced defects but that this pinning does not give rise to a corresponding change in internal friction.