The deformation twin in lamellar Ti3Al/TiAl structure

A Ti-48Al-2Cr (at.%) alloy consisting of γ+α2 lamellar structure was deformed in compression at room temperature. Study by high resolution electron microscopy was carried out on the characteristic of induced γT/α2 interface. During deformation the γT/α2 interface presents a stepped structure and the γ/α2 interface remains straight. The formation mechanism of γT associated with misfit dislocations is proposed. 1/2[011̄]γ interfacial dislocation in the γ/α2 interface can dissociate into a 1/6[1̄12̄]γ partial dislocation which glides on the (1̄11)γ plane and causes γT to form.