Published online by Cambridge University Press: 26 February 2011
Information on APB energy in ordered alloys is important not only to understand their mechanical properties but also to analyse conditions for phase transformation. APB surface energies are determined from dissociation distances of superdislocations both in TiAl and Al3Ti Medium and high APB energy anisotropies are found in TiAl and Al3Ti respectively. These results are consistent with phase diagram studies which predict that the APB energy vanishes in the (001) plane near the Al3Ti composition. Examples of decompositions of perfect dislocations into perfect dislocations are discussed.