The Effect of Annealing on the First Hydrogenation Behavior of Atomized Ti48.8Fe46.0Mn5.2 Alloy

In this paper, we report the effect of annealing on the first hydrogenation behavior of Ti48.8Fe46.0Mn5.2 alloy. This alloy was produced by gas atomization, and a portion of the powder was subjected to vacuum annealing at 1120 °C for 1 h. The goal was to investigate the usefulness of this atomized powder for hydrogen storage and also to investigate the effect of annealing. Scanning electron microscopy (SEM) images revealed that both atomized and annealed alloys exhibit a two-phase structure. The atomized alloy consists of a main TiFe matrix and a filamentous Ti2Fe-like phase. After annealing, the microstructure is globular. In addition to the microstructure, there was a change in the chemical composition of the matrix and secondary phase after annealing. The first hydrogenation at room temperature of both atomized and annealed samples required cold rolling. However, the kinetics was much slower for the annealed sample compared to the atomized sample. After the first hydrogenation, the XRD analysis identified the main phases as TiFe, TiFeH0.94, and Ti2FeH3, indicating that both the TiFe and Ti2Fe phases participated in hydrogen absorption during hydrogenation.