Series stacking of phases and lots of defects appear in rolling microstructure.

Cold rolling membrane shows much lower hydrogen permeability than the as-cast one.

Annealing for the cold rolled membrane is effective to improve its permeability.

A hydrogen flux of ~21 cc H₂ cm⁻² min⁻¹ is derived for the rolled-annealed membrane.

Rolling and annealing is promising to produce high-performance alloy membranes.