Effect of ball milling on the first hydrogenation of TiFe alloy doped with 4 wt% (Zr + 2Mn) additive

In this paper, we report the microstructure and hydrogen storage properties of TiFe + 4 wt% (Zr + 2Mn) alloy before and after high-energy milling. The as-cast sample was made of a main TiFe phase with a Zr- and Mn-rich secondary phase. We found that ball milling can significantly reduce the crystallite size of TiFe + 4 wt% (Zr + 2Mn) alloy. First hydrogenation measurements showed that the sample milled for 15 min displayed a faster hydrogenation than the as-cast sample but with a slight loss of capacity. Further milling made the samples totally inert to hydrogen. It may be concluded that the as-cast alloy has a special microstructure that is possibly destroyed by milling.