Dendritic structural transformation of laser surface remelted γ-TiAl based alloy during post-heat treatment

Laser surface remelting followed by heat treatments at 1000 °C for different time was carried out on γ-TiAl based alloy. The characteristics of structural transformation of laser surface remelted γ-TiAl based alloy were investigated by high-temperature microscope, TEM and XRD. The results show that the phase transformation (α2 → γ) in TiAl alloy occurred at the earlier stage of post-heat treatment, and the dendritic structure transformed firstly at the intergranular, then expanded into the transgranular, finally changed to ultrafine equiaxed grain structure, at the same time, micro-hardness of laser-surface remelted γ-TiAl based alloy had the corresponding change with the structural transformation.