Reversible hydrogen absorption in a Ti-6Al-4V alloy produced by mechanical alloying

• A nanostructured Ti-6Al-4V alloy was prepared by ball milling.
• The alloy showed a 1.8 wt% hydrogen storage capacity with no hydride formation.
• The desorption curve demonstrated a significant shift to lower temperatures.
• After hydrogenation, the existence of a supersaturated α phase was observed.

Hydrogen absorption in a Ti-6Al-4V alloy prepared by ball milling was investigated in view of the reversible storage of hydrogen in a solid state. The material characterization by X-ray and neutron diffractometry demonstrated the formation of a single α phase whose unit cell expanded during the hydrogen absorption. The maximum storage capacity of this α phase was 1.8 wt% H and no hydride formation was observed. The existence of such a particular supersaturated hexagonal phase was attributed to the strongly defective structure formed by the mechanical alloying process.