Internal friction in hydrogen-charged palladium

Abstract

The work has been suggested by the fact that in pure metals with dislocations, the point defects, such as impurity atoms, may give rise to thermally activated elastic relaxation effects. Palladium has been chosen as metal basis and hydrogen as interstitial because palladium is absorbent of hydrogen, which may be introduced with an electrolytical process and degassed with the electrolytical opposite process, without any change of dislocation density in the material. The experiments show that an electrolytic charge of hydrogen atoms of the order of 0.4.10-3 per palladium atom modify theQ−1(T) curve of the permanently strained material at low temperatures. The characteristic relaxation effects due to the dislocation motion (Bordoni peaks) disappear, while a new relaxation is introduced. A structural explanation of the relaxation is proposed that is based on an interaction mechanism between impurities and dislocations.