Fig. 1. SEM-BSE images and unrolled HEXRD rings of the Ti-45Al-8.5Nb-0.2B-0.2W-0.02Y alloy before (a, b) and after (c, d) heat treatment at 1280 °C for 5 h.

Fig. 2. The true stress-strain curves of samples compressed at 800 °C and 1000 °C up to an engineering strain of 0.3 in a strain rate of 0.001 s-1.

Fig. 3. SEM-BSE images and unrolled HEXRD rings of the samples compressed with the engineering strain of 0.3 and the strain rate of 0.001 s-1 at different temperatures: (a, b) 800 °C and (c, d) 1000 °C.

Fig. 4. (a, b) SEM-BSE images of the samples compressed at 800 °C; (c) TEM image of the βo(ω) areas; (d) HRTEM image of the formation of ωo phase in the βo matrix.

Fig. 5. TEM and HRTEM images of the samples deformed at 800 °C. (a, b) The coarsened α2 laths during high-temperature annealing decomposed into ultrafine lamellae, indicating α2→α2+γ decomposition in the lamellar colony; (c) HRTEM image of the remaining terminated α2 laths; (d) a high density of deformation twins are activated inside the ultrafine γ laths; (e) the dynamic recovery leads to the formation of sub-grain boundaries; (f) the thick γ laths are heavily deformed; (g) dynamic recrystallized grains occur due to significant internal stress at the twin intersection zone.

Fig. 6. (a) TEM image of recrystallized γ and globular ωo grains within ultrafine lamellae in the samples deformed at 800 °C; (b) HRTEM image of a deformation twin in the recrystallized γ grain; (c) HRTEM image of the SFs within the ωo grain.

Fig. 7. SEM-BSE and TEM images of the samples compressed at temperature 1000 °C.