H Diffusion in the H-stored TiVMnCr Alloys as Deduced from Absorption and Mechanical Spectroscopy Experiments

The low H content portion of the PCT absorption curves of the 40Ti-xV-(50-x)Mn-10Cr alloys exhibits a plateau, whose pressure has been determined together with the solubility limit of H in the ?-phase (solid solution). The chemical (Dc) and Einstein (DE) diffusion coefficients of H have been deduced from H absorption kinetics (273 K-1100 K) and from mechanical spectroscopy (150 K-200 K), which has revealed a Snoek-type of anelastic relaxation. The combined Arrhenius plot of DE and Dc gives the following parameters for H diffusion: W=0.318±0.005 eV, D0=(4±1)×10-7 m2/s (36 V alloy) and W=0.352±0.005 eV, D0=(5±1)10-7 m2/s (32 V alloy).