Hydrogen in the Ti3Al intermetallic compound: Study by the NMR method

Abstract

The times of nuclear spin–lattice relaxation have been measured and the spectra of NMR for ¹H and ²⁷Al in Ti₃AlH_x hydrogenated intermetallic compounds with hydrogen concentrations of х = 0, 0.31, 0.51, 1.0, 2.0, and 4.32 in a wide range of temperatures (10–500 K) and resonance frequencies (8.2–90 MHz) have been recorded. The analysis of low-temperature relaxation data has shown that the addition of hydrogen with a concentration of х ≥ 2 leads to a significant change in the density of electron states at the Fermi level. It has been found that the hydrogen mobility in Ti₃AlH_x strongly depends on its concentration. For solid solutions of hydrogen in Ti₃Al with х < 1, the mobility of hydrogen atoms on the scale of frequencies of NMR in the investigated temperature range has not been detected. In Ti₃AlH_x compounds with х ≥ 2, the fast diffusion of hydrogen is observed, which can be related to changes in the structure of these compounds.