Improvement of cyclic durability of Ti–Cr–V alloy by Fe substitution

Cyclic durability of hydrogen storage Ti–Cr–V alloys has been investigated. After 100 absorption/desorption cycles, Ti12Cr23V64Fe1 desorbs 2.34 mass% of hydrogen while Ti12Cr23V65 desorbs 2.19 mass% of hydrogen. These desorption capacities of Ti12Cr23V64Fe1 and Ti12Cr23V65 correspond to 97% and 88% of their initial capacities, respectively. The X-ray diffraction profiles of the alloys suggest that Fe substitution inhibits the increase of the lattice strain and the decrease of the crystallite size accompanied by hydrogen absorption and desorption. This inhibition most likely relates to the improvement of cyclic durability by Fe substitution.

► A small amount of Fe substitution improves cyclic durability of the Ti–Cr–V alloy.
► Fe substitution inhibits the lattice strain of the hydride phase.
► Fe substitution also inhibits the decrease of the crystallite size with cycles.
► The inhibition most likely relates to the improvement of cyclic durability.