Internal friction method in studying elastic modulus defect of PdH x solution due to mobility of hydrogen atoms

Abstract

The internal friction method in the free oscillation mode was used to study the temperature dependences of the dissipation loss spectra and shear modulus in a Pd polycrystalline system, PdH0.5 interstitial solid solution, and dehydrogenated Pd system. It is found in the studies of spectra and shear modulus that full hydrogen desorption from a- and b-phases of the PhH0.5 system occurs after the first heating cycle of the system. The dehydrogenated system, like the initial system, features the same number of peaks in the internal friction spectrum in the temperature range of 50–150×C. The temperature dependences of the shear modulus of the initial and dehydrogenated systems coincide. The presence of dissipative processes in the solid solution is related to mobility of hydrogen atoms in a FCC structure of Pd and causes a modulus defect in the temperature range of appearance of loss peaks in the spectrum. The possibility of describing the modulus defect within the phenomenological models in the inelasticity theory is considered.