Abstract: Demanding activation conditions hinder the application of TiFe-based alloys, while introducing a secondary phase would be promising in addressing this problem. This work chooses a Ti_0.9Zr_0.1Mn_1.5Cr_0.5 (TiMn₂-type) alloy with considerable hydrogen storage content and powder-sinters it with the TiFe_0.85Mn_0.12 (TiFe-type) alloy. The activation properties of the TiFe-x wt. %TiMn₂ (x = 10, 20, and 30) alloys are significantly improved, and all of them are able to activate without high-temperature process. The TiMn₂ phase addition yields a well-distributed internal phase interface, and the high dislocation density located at the interface facilitates hydrogen absorption at room temperature. The TiFe-30 wt. %TiMn₂ alloy reaches 90% of the maximum hydrogen absorption content at 303 K within 1000 s. Although the hydrogen absorption content decreases slightly, the cycling stability is remarkably promoted. The TiFe-30 wt. %TiMn₂ alloy presents a high hydrogen absorption retention rate, 98%, after 50 cycles. This work is expected to achieve activation for TiFe-based alloys by regulating phases.

Key words: TiFe-based alloy, Dual-phase alloy, Phase interface, Activation property, Cycling stability