Planar debris in plastically deformed Al-rich γ-TiAl

Transmission electron microscope images of aluminium-rich L10 TiAl samples deformed up to 400°C exhibit faint fringes spread uninterruptedly all over the thin foils. At variance from the fringe systems usually associated with stacking faults and/or antiphase boundaries, these faint striations show no clear spatial limitations by intersections with free surfaces or else by dislocations. The striation contrast is related to slip on {111} planes in either one of the 〈110] and 〈011] directions. It originates from modest atomic relaxations. The generation of the defects responsible for the striations is discussed in terms of non-localized slip in the presence of a short-range ordered phase, Ti3Al5, in Al-rich TiAl.