Elastic energy dissipation effects in α + β and β phase composition ranges of the palladium-hydrogen system

Abstract

Elastic energy dissipation (internal friction) peaks, arising from both stress-induced, bulk lattice rearrangements of hydrogen interstitials (H₍₁₎ peak) and hydrogen dislocation interactions (H₍₂₎ peak), have been investigated over a wide range of the hydrogen content in alpha + beta and beta phase concentration ranges of the Pd-H system during both absorption and desorption of hydrogen. It has been confirmed that the H₍₁₎ peak is associated with a Zener type of relaxation process. In beta phase regions, asymmetries of the H₍₁₎ peak have been observed, which may be accounted for by a Curie-Weiss law type of temperature dependence of the relaxation strength. Differences in the degree of short-range order in beta phase regions have been suggested by the form of the dependence of relaxation strength upon hydrogen content. It has been found that the H₍₂₎ peak only appears significantly in alpha phase and alpha + beta phase concentration ranges.