Samples of Ti–50 at.% Al–2 at.% Nb–2 at.% Mn, which have been ice–water quenched from the α-phase region, have been shown to transform via a massive transformation to the γ-phase. Examination of the massively transformed region shows that the γ-phase contains regions which show contrast which is very similar to that shown by antiphase boundaries. Part of these boundaries give rise to diffraction maxima, and it appears that a discrete phase may be present in these parts of the boundaries. The significance of these observations is discussed in terms of the factors which can give rise to the observed behaviour.