THE ROLE OF CONTROLLED RECRYSTALLIZATION TREATMENTS ON DUCTILITY OF FE3AL ALLOYS

Careful heat treatments after mechanical processing can lead to optimised mechanical properties of Fe3Al-base intermetallics that is to high strength combined with maximum ductility. These heat treatments are shown to lead to recovery of the dislocation structure introduced by prior working such that a fine subgrain structure is established. The subgrain boundaries are constituted of networks of [100] dislocations that are hence essentially immobile at room temperature. These boundaries are effective obstacles to the [111] dislocations mobile during room temperature deformation and ensure that deformation is distributed uniformly throughout the grains. It is this homogeneous distribution of strain that is responsible for the good strength and ductility.