Anelastic relaxation in ZrV2Hx intermetallic compounds

The anelastic spectrum of two intermetallic polycrystalline ZrV2Hx samples (0 ≤ x ≤ 0.09) has been investigated from 1 to 600 K in the frequency range 2–50 kHz. Besides the well-known martensitic phase transformation around 120 K, two thermally activated peaks are detected in the H doped alloys around 230 and 410 K at a vibration frequency of about 3 kHz. The process at the lower temperature is due to the jumps of H atoms likely among tetrahedral interstitial sites in the cubic lattice of the Laves phase. The profile can be satisfactorily fitted with the superposition of two peaks, broader than single time Debye relaxations, with activation enthalpies of 0.33 and 0.41 eV.The peak above room temperature, which appears only on the sample containing impurity phases (primary solution phase of vanadium and zirconium), presents features which suggest a mechanism involving the interaction between point defects and dislocations.