Thermal Stability of Nonequilibrium Lamellar Structure in γ-TiAl-based Two-phase Alloy

The structural changes of nonequilibrium interlamellar boundaries with a relatively high strain energy during subsequent 800℃, 15 min, WQ and 1000℃, 4 min, WQ annealing were studied by the conventional and high resolution transmission electron microscopy in the hot-forged Ti-45Al-8Nb-2.5Mn-0.05B alloy. The structural relaxations are mainly as following:further bending of interlamellar boundaries, necking and spheroidization process of α₂ plates, formation of subgrain boundaries within γ plates, etc..