Transmission of the deformation through γ-γ interfaces in a polysynthetically twinned TiAl alloy I. Ordered domain interfaces (120° rotational)

Atomistic study of ordinary screw dislocations in single-phase and lamellar γ-TiAl

“…These dislocations can glide further in the adjacent lamella under an increasing applied stress, because the directions of their Burgers vectors on either of the twin boundary coincide. In agreement with TEM observations and empirical slip transmission rules [33,34] the atomistic simulation of ordinary dislocation transfer to the adjacent lamella takes place without any dislocations remaining on the interface. Ordinary screw dislocations recover their typical core structure once they have left the boundary, spreading into two {111} planes, and their glide again becomes a zigzag motion on (111) and (111) planes.…”

Migration of ordered domain boundaries and its effect on the lamellar interfaces in Ti?Al-based alloys

“…On a microscopic scale, the nucleation mechanisms of dislocations and those of interface crossing have been found to be aOE ected by the intrinsic nature of the interfaces (Zghal et al 2001, Zghal andCouret 2001). It follows that further investigations are required, taking into account the intrinsic nature and the distribution of the diOE erent types of lamellar interface.…”

Plastic deformation along the plane with zero resolved shear stress

“…The basic argument for the activation of ordinary dislocations together with deformation twinning is a tendency to eliminate propagation of plastic flow across the interfaces that are strong obstacles for deformation twinning as well as for dislocation slip. Let us note that the transfer of plastic deformation across the lamellar interfaces has been recently studied experimentally by post-mortem observations [13,15] and by in situ electron microscopy [16,17]. The behaviour of ordinary dislocations has been examined in detail in the series of papers [18][19][20].…”