Cycle durability of Ti–Cr–V alloys partially substituted by Nb or Fe

Abstract

• The effect of substitution with Nb and Fe on the cycle durability is investigated. • For up to 8 at% Nb, the alloys showed better cycle durability than Ti–Cr–V alloy. • 5 at% Nb is preferable for highly hydrogen storage capacity and cycle durability. • Cycle durability was improved with 1 at% Fe, but hydrogen storage capacity decreased. The effect of partial substitution with niobium and iron in Ti 25 Cr 50 V 25 hydrogen storage alloys on the short term cycle durability during hydrogen absorption and desorption is investigated. The substitution of 1 at% iron improved the cycle durability, although the hydrogen storage capacity decreased. In contrast, partial substitution by niobium was effective in improving the cycle durability while maintaining the hydrogen storage capacity. For up to 8 at% niobium substitution, the alloys showed a single bcc phase and better cycle durability than the Ti 25 Cr 50 V 25 alloy. This study showed that a niobium substitution of 5 at% is preferable for highly effective hydrogen storage capacity and cycle durability.