Continuous Coarsening Mechanism of Lamellar Microstructure in Ti-48Al Alloy

The continuous coarsening mechanism of the fully lamellar microstructure of Ti\|48Al alloy aged at 1150℃ was studied by TEM. The continuous lamellar coarsening could be occurred not only by the interface faults (such as: ledges, edges and curved interfaces) migrating, but also by the migration and dissolution of γ/γ lamellar interfaces. Among the true\|twin, pseudo\|twin and 120°\|rotational ordered types γ/γ lamellar interfaces, the thermal stability of the 120°\|rotational ordered interface was the lowest, it was migrated or dissolved frequently. The thermal grooves were often formed at the triple point junctions between the 120°\|rotational ordered domain boundaries in γ lamella and the lamellar interfaces, which was the original dissloution position of the lamellar interfaces.