Protium absorption and desorption properties of bcc Ti-Fe solid solution alloys stabilized by Mo addition

Abstract

The present study investigates the effect of Mo addition to the TiFe alloys on a stabilization of bcc phase and their protium absorption and desorption properties. Ti0.5Fe0.5 alloys with more than 10 mol% Mo had CsCl phase and bcc phase, which show single plateaus in the PCT curves and were easily hydrogenated without homogenization. The bcc phase has larger lattice parameter than that of the CsCl phase. TiFe-10 mol% Mo annealed alloys with the Ti/Fe ratio of more than 2 had a bcc phase as a main phase and CsCl as a minor one. The alloys had 3 mass% of the maximum protium capacity and desorbed protium only 1 mass%. The phases of the hydrogenated alloy were fee and orthorhombic structure, which may be caused by di-hydrides of bcc solid solution and mono-hydrides of CsCl phase, respectively. It is found that the Mo addition to TiFe alloys could stabilize bcc phase and enhances the hydrogenation reaction of the disordered bcc Ti-Fe-Mo phase similar to Ti-Cr-X bcc alloys.