Antiphase domains and {011} twins in TiAl

Abstract

Titanium aluminides with a TiAl/Ti₃Al two-phase microstructure exhibit mechanical properties which are superior to those for either single-phase TiAl or Ti₃Al. The TiAl lamella in the two-phase microstructures show differently oriented TiAl regions which are frequently observed to coexist within the same TiAl lamella. The atomic arrangements of these regions are similar to antiphase domains/{011} twins of TiAl. However, the mechanism by which these regions are formed cannot be derived from the TiAl phase alone. This study suggests that, for two-phase titanium aluminides, Ti₃Al has a strong influence on the development of the TiAl microstructure.