DEFORMATION PROCESSES RELATED TO INTERFACIAL BOUNDARIES IN 2-PHASE GAMMA-TITANIUM ALUMINIDES

The deformation behaviour of two-phase (alpha2 + gamma) titanium aluminide alloys with a lamellar microstructure was investigated by conventional and high resolution electron microscopy. With regard to the mechanical properties, the structures of the interfacial boundaries occurring in these materials are characterized and the interaction mechanisms of the deformation processes with these interfaces is investigated. Accordingly, the misfit dislocations present at semicoherent alpha2/gamma and gamma/gamma interfaces assist the generation of dislocations and deformation twins. On the other hand, the semicoherent interfaces act as very effective barriers impeding the propagation of slip across the lamellae.