Samples Mg-14Ni-6Fe(2)O(3), Mg-14Ni-3Fe(2)O(3)-3Ti, and Mg-14Ni-2Fe(2)O(3)-2Ti-2Fe were prepared by reactive mechanical grinding, and their hydrogen storage properties were examined. The activated Mg-14Ni-2Fe(2)O(3)-2Ti-2Fe had the highest hydriding rate, absorbing 4.14 wt% H for 5 min, and 4.27 wt% H for 10 min, and 4.42 wt% H for 60 min at 573 K under 12 bar H-2. The activated Mg-14Ni-3Fe(2)O(3)-3Ti had the highest dehydriding rate, desorbing 3.81 wt% H for 20 min, 3.98 wt% H for 25 min, and 4.15 wt% H for 60 min. Mg-14Ni-6Fe(2)O(3) dehydrided at n = 4 contained Mg, Mg2Ni, MgO, and Mg(OH)(2). Mg(OH)(2) is considered to be formed by the reactions of MgH2 or Mg with water vapor. The effects of reactive mechanical grinding and hydriding-dehydriding cycling are the creation of defects and cracks, and the reduction of Mg particle size. The addition of a larger amount of Ti and/or Fe has stronger effects of reactive mechanical grinding, whereas the addition of a larger amount of Fe2O3 has greater effects of hydriding-dehydriding cycling. (C) 2012 Elsevier Ltd. All rights reserved.