Effects of α 2 lamellae on deformation and fracture in fully lamellar TiAl based alloys

Abstract

The deformation and fracture behaviours in fully lamellar TiAl alloys were investigated by unixial compression and an in situ TEM technique. The results indicated that the deformation and fracture behaviours in fully lamellar TiAl alloys were closely related to the relative orientation of the lamellae to the loading axis. When the lamellae were parallel to the loading axis, the slip in the α₂ phase occurred along its prism plane, and microcracks nucleated preferentially along its prism plane. When the lamellae were perpendicular to the loading axis, slip became difficult, slip in the α₂ phase occurred along its pyramidal plane, microcracks nucleated and propagated preferentially along its lamellar interface.