Hydrogen storage in Ti-Zr/Hf-Ni quasicrystal and related crystal powders synthesized by mechanical alloying

The dominant cluster in the Ti/Zr-based quasicrystals is a Bergman-type cluster possessing a large number of tetrahedral interstitial sites; this makes these quasicrystals attractive as potential hydrogen storage materials. This paper summarizes our recent research results on the hydrogen absorption and desorption properties of the Ti-Zr-Ni and Ti-Hf-Ni quasicrystals and related amorphous or crystal phases produced by a combination of mechanical alloying and subsequent annealing. The effects on the microstructures and hydrogenation properties of the substitution of Zr for either Ti or Hf in alloys based on the Ti₄₅Zr₃₈Ni₁₇ compositions are investigated. Comparisons between results reported for samples prepared by rapid quenching or annealing are also made.