Investigations of hydrogen-promoted α2-lamella decomposition of a γ-TiAl based alloy

The effect of hydrogen on α2-lamella decomposition of a Ti-46Al-2V-1Cr-0.3Ni alloy (at%) was investigated. The extent of α2-lamella decomposition was enhanced due to hydrogen addition, which was partly attributed to hydrogen-promoted α2→B2 phase transformation and α2-phase lamellae coarsening. When the deformation temperature rose to 1473 K, hydrogen-promoted γ-phase twinning and α2-phase dislocation movement played a positive role in α2-lamella decomposition.