Precipitation of Ti2Al phases at lamellar interfaces in a high-Nb-containing TiAl alloy during thermal exposure

•Excess α2 phases in the as-cast high-Nb-containing TiAl alloy were decomposed during thermal exposure at 950 °C.•Ti2Al phases precipitated at lamellar interfaces during thermal exposure at 950 °C.•Stacking faults generated from the α2 → γ phase transformation provided nucleation sites for Ti2Al phases.