Hydrogenation properties of Fe–Ti–V bcc alloys

The hydrogenation properties of Fe–Ti–V bcc alloys have been studied by the Sieverts method. Starting from a fully determined ternary phase diagram, a large number of compositions have been synthesized and pressure–composition–isotherms have been measured at different temperatures both in the low and high hydrogen concentration regions. The enthalpies of absorption and desorption have been found to vary linearly as a function of composition in the ternary domain and depend on the ones of the pure elements. The absorption capacity is mainly dependent on the iron concentration. Additionally, the crystal structure of the hydrides has been studied. For the first time a progressive and continuous distortion from body centered cubic (bcc) to body centered tetragonal (bct) structure has been evidenced.

Research highlights▶ Hydrogen gas storage properties obtained from a fully determined Ti–V–Fe ternary phase diagram. ▶ Enthalpies of absorption and desorption linearly related to the composition of the ternary bcc domain. ▶ Progressive and continuous distortion from (bcc) to (bct) structure evidenced for the first time.