Published online by Cambridge University Press: 15 February 2011
The transmission of shear across the interfaces between lamellae of γ-TiAl and α2-Ti3Al has been studied in the case of a room temperature deformed Ti-48A1 alloy containing a significant proportion of the lamellar microstructure. The mechanisms of shear transmission due to dislocation slip has been studiedusing transmission electron microscopy. Dislocations with Burgers vectors given by b=1/3 <1120>are the only products of slip transmission from the γ-TiAl phase to the α2-Ti3Al phase, and essentially no dislocations with b=1/3 <1126> i.e. c-component dislocations, have been observed. Slip transmission has been associated with impingement of certain cross-lamellar twins, formed by deformation in γ-TiAl, with the α2 lamellae. Dislocation based models for the slip transmission processes are proposed.