Hydrogenation properties of nanocrystalline Ti V Mn body-centered-cubic alloys

Abstract An effect of Mn content in nanocrystalline Ti V Mn alloy on hydrogenation properties has been investigated systematically in this work. Ti 0.5 V 1.5-x Mn x (x = 0, 0.1, 0.2, 0.3) alloys are synthesized by mechanical alloying method. It has been shown that all alloys need to be activated in order to present the best hydrogenation properties. With increasing Mn content in Ti V Mn alloys, the maximum hydrogen storage capacity at room temperature firstly increases to reach 3.07 wt% for Ti 0.5 V 1.4 Mn 0.1 alloy and then gradually decreases. Reversibility of hydriding-dehydriding process improves after chemical modification of Ti V alloy. Hydrogen storage properties result from phase composition and structure of alloys. All samples are composed of a major body-centered-cubic (BCC) phase. In Mn-containing materials also a second BCC phase has been detected. Its abundance increases with higher content of Mn in the alloy. Moreover, with increasing Mn content, the lattice parameters of both phases decrease.