Dynamic observation of dislocation movement across twin boundaries in the lamellar structure of TiAl intermetallic compound

Mechanisms of enhancement of plastic deformation in TiAl responsible for ductility improvement of this material, have been studied by high-voltage electron microscopy (HVEM) and atom probe field ion microscopy (AP-FIM). During cross-twinning, a dislocation interaction occurs at twin boundaries. Dislocation networks and fine Ti3Al particles on the pre-existing twin boundaries promote the formation and movement of twinning partial dislocations, contributing to an improvement of ductility. (orig.)